JP4350776B2 - Isolated operation detection system and isolated operation detection device for distributed power supply - Google Patents

Description

  The present invention is a system having a configuration in which a plurality of distributed power holding facilities having a distributed power source are connected to a distribution line of a distribution system in which a distribution line is connected to a host system via a substation. The present invention relates to an isolated operation detection system configured to detect an isolated operation. Furthermore, the present invention relates to an isolated operation detection device that detects an isolated operation of a distributed power supply in a subsequent distributed power supply facility that is a member of the isolated operation detection system.

  For example, when a ground fault including a contact accident between high voltage and low voltage occurs in the distribution line, the substation detects this and opens the circuit breaker in the substation.

  When a distributed power supply facility having a distributed power supply is connected to the distribution line, the distributed power supply becomes an independent operation by opening the circuit breaker. If this isolated operation is continued, electric power continues to be supplied from the distributed power supply, and thus there is a possibility that a ground fault including the above-mentioned accident in contact will continue. Therefore, it is necessary to quickly detect the isolated operation of the distributed power source.

  In particular, when a large number of distributed power supplies with reverse power flow (that is, there is a flow of active power from the distributed power supply to the system side) in low-voltage interconnections such as household solar power generation equipment and fuel cell equipment are connected to the distribution line There is a high possibility that the ground fault will continue.

  Therefore, in order to prevent isolated operation of the distributed power supply, as described in Non-Patent Document 1, each distributed power supply facility has a device having a function of detecting the independent operation of the distributed power supply in the own facility (that is, It is necessary to provide an isolated operation detection device). Non-Patent Document 1 describes various methods as an isolated operation detection function.

  Note that the distributed power supply facility is, for example, a power generation facility having a distributed power source, a home, a supermarket, a factory, or other facilities.

  As an example of an isolated operation detection device, a current injection device that injects an injection current having an injection frequency that is different from the fundamental frequency of the distribution system into a distribution line through a lead-in line that connects the distributed power supply facility and the distribution line, and An isolated operation detection device comprising an isolated operation monitoring device that measures the voltage of the injection frequency in the lead-in line and detects from the increase in the voltage that the distributed power supply in the distributed power supply facility has become independent operation. It is done.

  In that case, it is necessary to synchronize between injection currents injected from current injection devices of a plurality of distributed power supply facilities connected to the same distribution line.

  If synchronized, each injection current is synthesized, so even if each injection current is small, a plurality of injection currents gather to become a large injection current, thereby increasing the injection frequency voltage generated by the injection current, The sensitivity, accuracy, reliability, etc. of the isolated operation detection using the voltage are increased.

  If the synchronization is not achieved, not only the plurality of injection currents are not synthesized well, but also the plurality of injection currents work to interfere and cancel each other (for example, injection currents that are 180 degrees out of phase cancel each other and become zero). ), It becomes difficult to detect isolated operation.

  As one technique for synchronizing a plurality of injection currents, Patent Document 1 describes a technique in which a synchronization signal line is specially provided and used. In Patent Document 1, the injection current is described as a disturbance signal.

  However, as described in Patent Document 1, in the technique using the synchronization signal line, (a) it is very difficult to install the synchronization signal line, and (b) there is a risk of disconnection of the synchronization signal line. There is a problem of being.

  Therefore, as another technique for synchronizing a plurality of injection currents, Patent Document 1 includes an external synchronization signal receiving means for receiving an external synchronization signal from an external synchronization signal source other than the isolated operation detection device. A technique for using the external synchronization signal as a common synchronization signal is described. The external synchronization signal is, for example, a standard radio signal for a radio clock or a GPS signal.

“Distributed Power System Interconnection Technology Guidelines (Electrical Technology Guidelines Distributed Power System Interconnection)”, JEAG 9701-2001, Japan Electric Association Distributed Power System Interconnection Special Committee, April 15, 2002 Second edition, 3rd edition, pages 38-45 JP 2006-262557 A (paragraphs 0016, 0017, 0021, 0029, FIG. 1)

  The technique using the external synchronization signal described in Patent Document 1 has a problem that an external synchronization signal source is required. This external synchronization signal source is originally a signal source that has nothing to do with the isolated operation detection device, and the use of such a signal source maintains the reliability of isolated operation detection and the miniaturization and economy of the device. It is not preferable from the viewpoint. For example, there is a possibility that reception cannot be performed outdoors or where there is a lot of radio noise, or transmission may be interrupted. In addition, if a receiving antenna is provided separately as a countermeasure against poor reception, the size and economy of the device are impaired.

  Accordingly, the present invention provides an isolated operation detection system that can synchronize injection currents injected into a distribution line from a plurality of distributed power supply facilities without using a synchronization signal line or an external synchronization signal source as described above. One purpose is to provide.

  Also, an isolated operation detection device for detecting isolated operation of a distributed power supply in a subsequent distributed power supply facility that becomes a member of the isolated operation detection system, using a synchronization signal line or an external synchronization signal source as described above An independent operation detection device that can synchronize the injection current injected from the current injection device into the distribution line with the injection current of the same frequency injected by the current injection device of the distributed power supply equipment belonging to the same group. The other purpose is to provide.

  In the isolated operation detection system according to the present invention, a plurality of distributed power holding facilities having a distributed power source are connected to a distribution line of a distribution system in which a distribution line is connected to a host system via a substation, and each distributed A power supply facility is a current injection device that injects an injection current having an injection frequency that is different from the fundamental frequency of the distribution system into the distribution line through a lead-in line that connects the distributed power supply facility and the distribution line. A single operation monitoring device that measures the voltage of the injection frequency in the lead-in line and detects from the increase in the voltage that the distributed power source in the distributed power source holding facility is in a single operation. In the operation detection system, (a) the plurality of distributed power source holding facilities are classified into two groups of a first group and a second group, and (b) each of two injection frequencies that generate beats. The frequency difference between the two injection frequencies of each set is the same as each other, and the four injection frequencies constituting both sets are different from each other in the first set and the second set. Using the injection frequency, (c) the current injection device of each distributed power supply facility belonging to the first group is set with the first set of injection frequencies and injects an injection current including the current set of the injection frequency, The isolated operation monitoring device of the power supply facility is configured to detect at least one injection frequency of the second set of injection frequencies, measure the voltage of the injection frequency, and detect the isolated operation. ) The current injection device of each distributed power supply facility belonging to the second group is set with a second set of injection frequencies and injects an injection current including the current set of the injection frequency, and the single operation monitoring device of the distributed power supply facility Is the first set of injection frequencies At least one of the injection frequencies is set and the voltage of the injection frequency is measured to detect the islanding operation. If the group to which the current equipment belongs is called the other group, and the group to which the own equipment does not belong is called the other group, the phase of each current of the current set constituting the current injected by the current injection device of the own equipment In addition to maintaining the same phase relationship common within the same group with respect to the phase of the own equipment beat that is generated, the current injection of the equipment installed by the current injection device of the distributed power supply equipment belonging to the other group Each of which is provided with a synchronization control device that synchronizes with another group of beats, which is a beat of the voltage generated by the whole.

  In summary, this islanding operation detection system synchronizes the injection currents of the same frequency within its own group, and generates the injection current of its own equipment and the generation of the injection current of the other group. Is used to synchronize. In other words, the synchronous control device (a) sets the phase of each current of the current set constituting the injection current injected by the current injection device of its own equipment relative to the phase of its own equipment beat, which is the beat that the injection current generates. In addition to maintaining a constant phase relationship common within the same group, (a) the beat of the voltage generated by the total of the injected current injected by the current injection device of the distributed power supply equipment belonging to the other group. Synchronize with other groups.

  As a result of (a) and (b) above, the injected currents of the same frequency within the group are synchronized. Therefore, there is no need to use a conventional synchronization signal line or an external synchronization signal source.

  The synchronous control device (a) is a voltage included in the voltage in the lead-in line, and measures the voltage of the injection frequency of the current injection device of the distributed power supply facility belonging to another group, and based on the voltage The other group beat phase calculating means for calculating the other group beat phase, and (b) the phase of each current of the current set constituting the injection current injected by the current injection device of the own equipment is the phase of the own equipment beat. Current phase setting means for setting the phase of each current of the current set so as to have a common fixed phase relationship within the same group, and (c) the phase of the own equipment beat and the other group beat Find the phase difference from the phase, and set the phase of each current in the current set that constitutes the injection current injected by the current injection device of the own equipment so that the phase difference becomes a common constant value within the same group. The ratio between the amount of phase change Varied while maintaining the same ratio as the ratio between the constant frequency, the self equipment beat may be one and a beat synchronization means for synchronizing to the other group beat.

  The synchronous control device (a) is a voltage included in the voltage in the lead-in line, and measures the voltage of the injection frequency of the current injection device of the distributed power supply facility belonging to another group, and based on the voltage The other group beat phase calculating means for calculating the other group beat phase, and (b) the phase of each current of the current set constituting the injection current injected by the current injection device of the own equipment is the phase of the own equipment beat. Current phase setting means for setting the phase of each current of the current set so as to have a common fixed phase relationship within the same group, and (c) the phase of the own equipment beat and the other group beat The phase difference from the phase is calculated, and the current set of the current set constituting the injection current injected by the current injection device of the own equipment is determined according to the phase difference so that the phase difference becomes a constant value common in the same group. The frequency of each current is the ratio between the two frequencies The increased or decreased while maintaining the ratio between the set frequency, the may be one and a beat synchronization means for synchronizing the self equipment beat to the other group beat.

(1) The synchronous control device (a) is a voltage included in the voltage in the lead-in line, and measures the voltage of the injection frequency of the current injection device of the distributed power supply facility belonging to another group, and the voltage The other group beat phase calculating means for calculating the other group beat phase based on the above, (b) a clock means for generating a signal representing the time t, and (c) the following beat phase difference. The phase coincidence time for generating the phase coincidence time T _e (t) ((t) indicates a physical quantity that varies with time, and so on) that makes the beat phase difference common to the same group. generating means, and matching the phase setting means for setting a match phase theta _e is a common fixed phase in (d) the same group, the two injection frequencies are the set form a set of self-equipment (e) Expressed as angular frequency ω _a , ω _b , the time t , A phase that generates two phases θ _a (t) and θ _b (t) expressed by Equation 1 or a mathematically equivalent expression using the phase matching time T _e (t) and the matching phase θ _e. Generating means; (f) self equipment beat phase calculating means for calculating a phase difference between the two phases θ _a (t), θ _b (t) and calculating the self equipment beat phase; A beat phase difference calculating means for calculating a beat phase difference that is a phase difference between the beat phase of the own equipment and the other group beat phase; (2) the current injection device includes: (a) the two Injection signal generating means for generating an injection signal including two sinusoidal AC signals each having the phases θ _a (t) and θ _b (t) using the phases θ _a (t) and θ _b (t); (B) injection current forming means for forming the injection current using the injection signal. It may be adopted.

[Equation 1]
θ _a (t) = ω _a (t−T _e (t)) + θ _e
θ _b (t) = ω _b (t−T _e (t)) + θ _e

  An isolated operation detection device according to the present invention is connected to a distribution line of the distribution system including the distributed operation isolated system, and one of the first group and the second group of distributed power holding facilities. (A) one of the first set and the second set is set with the injection frequency of the first set and the second set. A current injection device for injecting an injection current including a current set of the frequency into the distribution line through a lead-in line connecting the subsequent distributed power source holding facility and the distribution line; and (b) the subsequent distributed power source holding facility. Is a voltage in the lead-in wire for, and at least one injection frequency constituting the injection frequency of the other set of the first set and the second set is set and the voltage of the frequency is measured, From the increase in the voltage, An isolated operation monitoring device that detects that the distributed power supply in the subsequent distributed power supply facility is in an independent operation, and (c) the subsequent distributed power supply facility is called the own facility, and the own facility becomes a member. If the group of the distributed power source holding equipment is called the own group, and the group of the distributed power source holding equipment that is not the member of the own equipment is called the other group, the current injection device for the own equipment injects the injected current. The phase of each current in the current set is maintained in a constant phase relationship common within the same group with respect to the phase of the own equipment beat, which is the beat generated by the injected current, and the own equipment beat belongs to another group. And a synchronous control device that synchronizes with other group beats, which are voltage beats generated by the total of the injected currents injected by the current injection device of the distributed power supply facility.

  In the isolated operation detection device, the first set of injection frequencies is set in the current injection device, and at least one injection frequency constituting the second set of injection frequencies is set in the isolated operation monitoring device. If so, the subsequent distributed power supply facility becomes a member of the first group of distributed power supply facilities. Conversely, when the second set of injection frequencies is set in the current injection device and at least one injection frequency constituting the first set of injection frequencies is set in the isolated operation monitoring device, The subsequent distributed power supply facility becomes a member of the second group of distributed power supply facilities.

  The synchronous control device that constitutes the isolated operation detection device according to the present invention may employ substantially the same configuration as the configuration of the synchronous control device included in each of the distributed power supply facilities of the isolated operation detection system. .

  According to the isolated operation detection system of the present invention, a plurality of dispersions belonging to the same group are utilized by synchronizing the beat generated by the injection current of the own equipment and the beat generated by the injection current of the other group. A plurality of injected currents having the same frequency injected from the power supply facility to the distribution line can be synchronized. Therefore, there is no need to use a conventional synchronization signal line or an external synchronization signal source.

  According to invention of Claim 4, there exists the following further effect. In other words, the current phase setting means sets the phase of each current of the current set to 0 degrees when the phase of the beat of the equipment becomes 0 degrees, and when setting to 0 degrees, it is set to other than 0 degrees. Unlike the case, the configuration can be simplified because it is not necessary to provide a special setting means.

  According to invention of Claim 6, there exists the following further effect. That is, the coincidence phase setting means sets the coincidence phase when the phase of the beat of its own equipment becomes 0 degrees, and when it is set to 0 degrees, it is different from the case where it is set to other than 0 degrees. Since no special setting means is required, the configuration can be simplified.

  According to invention of Claim 7, there exists the following further effect. That is, since a frequency that is not originally present in the distribution system (very small even if it exists) is a non-integer multiple of the fundamental frequency, it is easy to measure the voltage due to the injected current. That is, the SN ratio is improved. As a result, the capacity of each current injection device can be reduced.

  According to invention of Claim 8, there exists the following further effect. That is, by causing a plurality of distributed power supply facilities to belong to the first group and the second group as described above, currents of the same frequency and the same phase included in the injected current are passed between the three lines of the three-phase distribution line. It is possible to prevent a circulating current from flowing through the injection device. If a current included in the injected current flows as such a circulating current, a voltage due to the current is not generated between the lines and it becomes difficult to detect an isolated operation, but this can be prevented.

  According to the islanding operation detection device of the present invention, by utilizing the synchronization between the beat generated by the current injection device for own equipment and the beat generated by the injection current of the other group, The injection current injected into the distribution line from the facility current injection device can be synchronized with the injection current of the same frequency injected by the current injection device of the distributed power supply facility belonging to the same group. Therefore, there is no need to use a conventional synchronization signal line or an external synchronization signal source.

(1) Whole isolated operation detection system FIG. 1 is a single line connection diagram showing an example of a power distribution system including a distributed power supply isolated operation detection system according to the present invention.

  This distribution system has a configuration in which a three-phase distribution line 10 is connected to a host system 2 via a substation 4. The substation 4 includes a transformer 6 and a circuit breaker 8 that connects the secondary side of the transformer 6 and the distribution line 10. Although the voltage of the distribution line 10 is 6.6 kV, for example, it is not restricted to this.

  A load 12 is connected to the distribution line 10. The load 12 shows a large number of loads collectively.

  In this example, a plurality of distributed power source holding facilities 20 having distributed power sources are connected to the distribution line 10 via a transformer 14 and a lead-in wire 16 connected to the secondary side thereof. To give a more specific example, a large number of low-voltage interconnected distributed power supply facilities 20 that have contracts with reverse power flow are connected at a high density. Each transformer 14 is a 6600V / 210V pole transformer, for example. A plurality of distributed power supply facilities 20 may be connected to one transformer 14.

  An example of the configuration of each distributed power supply facility 20 is shown in FIG. The distributed power supply facility 20 is a power conditioner including a distributed power source 26 composed of a direct current power source such as a solar cell or a fuel cell, an inverter (inverse conversion device) for converting the direct current power into alternating current power, and a system interconnection protection device. A current injection device for injecting an injection current having an injection frequency that is different from the fundamental frequency of the distribution system into the distribution line 10 through the service line 16 and the switch 22 provided between the power supply line 16 and the lead wire 16. 40 and an independent operation monitoring device 30 that measures the voltage of the injection frequency in the lead-in line 16 and detects from the increase in the voltage that the distributed power source 26 in the distributed power source possessing facility has become an independent operation. And a synchronization control device 50 that performs synchronization control. Details of each device 30, 40, 50 will be described later.

  An instrument transformer may be provided between the lead-in line 16 and the isolated operation monitoring device 30 and the synchronous control device 50 as necessary.

  In this isolated operation detection system, the plurality of distributed power supply facilities 20 are classified into two groups, a first group and a second group. However, the plurality of distributed power holding facilities 20 constituting the first group and the plurality of distributed power holding facilities 20 constituting the second group seem to be gathered together for each group for convenience of illustration in FIG. However, they may be mixed instead of gathering.

  The number of the distributed power source holding facilities 20 constituting the first group and the second group may be at least two each. After constructing the islanding detection system, the number of distributed power source holding facilities 20 constituting the first group and / or the second group may be changed (increased or decreased).

In addition, as shown in Formula 2 and Table 1, this isolated operation detection system has two injection frequencies each consisting of two injection frequencies that cause beat, and the frequency between the two injection frequencies forming each group. The difference Δf is the same in both sets, and the four injection frequencies f ₁₁ , f ₁₂ , f ₂₁ , and f ₂₂ constituting both sets use different first and second sets of injection frequencies.

These four frequencies f ₁₁ , f ₁₂ , f ₂₁ , and f ₂₂ are all set to frequencies different from the fundamental frequency of the distribution system. This is to facilitate discrimination (separation) from the fundamental frequency. The frequencies forming each set are set to frequencies close to each other to the extent that a beat is generated. The frequency difference Δf is also the beat frequency.

  In this specification and drawings, a physical quantity (such as frequency) having a subscript 11 in the reference numeral and a physical quantity having a subscript 12 indicate a first set, and a physical quantity having a subscript 21 and a physical quantity having a subscript 22 are a second set. Is shown.

[Equation 2]
| F ₁₁ −f ₁₂ | = | f ₂₁ −f ₂₂ | = Δf
f ₁₁ ≠ f ₁₂ ≠ f ₂₁ ≠ f ₂₂

The current injection device 40 of each distributed power supply facility 20 belonging to the first group injects an injection current I _inj including the current set of the injection frequency set with the first set of injection frequencies, The 20 independent operation monitoring devices 30 are configured to detect the isolated operation by setting the second set of injection frequencies and measuring the voltage of the injection frequency.

The current injection device 40 of each distributed power supply facility 20 belonging to the second group injects an injection current I _inj including the current set of the injection frequency set with the second set of injection frequencies, The 20 single operation monitoring devices 30 are configured to detect the single operation by setting the first set of injection frequencies and measuring the voltage of the injection frequency.

  In this embodiment, in order to further improve the reliability of the isolated operation detection, each isolated operation monitoring device 30 sets two injection frequencies constituting each set, measures the voltages of both injection frequencies, and independently Although it is configured to detect the operation, it may be configured to detect any single operation by setting one of the injection frequencies and measuring the voltage of the injection frequency.

The four frequencies f ₁₁ , f ₁₂ , f ₂₁ , and f ₂₂ are represented by four angular frequencies ω ₁₁ , ω ₁₂ , ω ₂₁ , and ω ₂₂ that are in a fixed relationship (that is, a relationship of ω = 2πf). Alternatively, it may be expressed by four orders with respect to the fundamental wave of the distribution system.

  Each of the injection frequencies constituting the first set and the second set of injection frequencies should be a non-integer multiple (that is, a fractional multiple) greater than one time the fundamental frequency of the distribution system. preferable. In such a case, since a frequency that is not originally present in the distribution system (very small even if it exists) and uses a non-integer multiple of the fundamental frequency is used, it is easy to measure the voltage due to the injected current. . That is, the SN ratio is improved. As a result, the capacity of each current injection device 40 can be reduced.

For example, the four frequencies f ₁₁ , f ₁₂ , f ₂₁ and f ₂₂ are 132 Hz (2.2 order), 144 Hz (2.4 order), 156 Hz (2.6 order), 168 Hz (2.8), respectively. Next). The values in parentheses are expressed as orders with respect to the fundamental wave of the distribution system (for example, 60 Hz = 1st order). In the following embodiments, the frequencies exemplified here are all used. However, it is not limited to this.

(2) About use of beat The reason why the frequency of the injection current and the frequency of the measurement voltage are divided as shown in Table 1 is as follows.

(A) If the current injection device 40 and the single operation monitoring device 30 of all the distributed power supply facilities 20 use the same single injection frequency, the single operation monitoring device 30 measures in one distributed power supply facility 20. voltage V _m of the injection frequency is that most monitors the injection current I ₂ voltage V ₂ by the injection current I ₁ according to voltages V ₁ becomes the own equipment 20 is injected, the other distributed power owned equipment 20 is injected I can't. This is because if the impedance of the distribution line 10 is Z _s and the impedance of the transformer 14 is Z _t , the voltages V ₁ and V ₂ are expressed by the following equations. Σ represents the total. In general, since Z _t >> Z _s , V ₁ >> V ₂ , and the voltages V ₂ having the same frequency are erased by the much larger voltage V ₁ and cannot be monitored. .

[Equation 3]
V ₁ = (Z _s + Z _t ) × I ₁
V ₂ = Z _s × ΣI ₂

  Therefore, when all of the distributed power supply facilities 20 use one injection frequency, it is impossible to monitor the voltage due to the injection current injected by the other distributed power supply facilities 20 and thus measure the phase of the voltage. The multiple injection currents cannot be synchronized.

(B) Also, suppose that the first group of distributed power supply facilities 20 uses one (first) injection frequency f ₁ , and the second group of distributed power supply facilities 20 uses the other (second) injection. If the frequency f ₂ (≠ f ₁ ) is used, the distributed power supply facility 20 in one group has a different frequency, and therefore the voltage due to the injection current injected by the distributed power supply facility 20 in the other group is monitored. However, since the frequency of the voltage due to the injection current of the other group and the injection current of the own facility 20 are different, the injection current of the own facility 20 cannot be synchronized with the voltage due to the injection current of the other group.

  That is, it is impossible to synchronize the plurality of injected currents in the own group with reference to the voltage due to the injected current of the other group. For example, even if an attempt is made to synchronize a plurality of injected currents in the own group with reference to the time of the peak value of the voltage due to the injected current of the other group, there are many times of the peak value and the time is determined as one time. This is because the plurality of injected currents in the own group are injected separately.

  (C) On the other hand, as shown in Table 1, since the distributed power supply facility 20 in one group has a different frequency, it depends on the injected current injected by the distributed power supply facility 20 in the other group. The voltage can be monitored. In addition, as shown in the above equation 2, a beat that causes an injection current from the distributed power source holding facility 20 in one group and a beat that causes an injection current from the distributed power source holding facility 20 in the other group. Are the same frequency Δf, so that both beats can be synchronized. The distributed power supply isolated operation detection system according to the present invention utilizes this. This will be further described below.

  In this specification, the group to which the own equipment (own equipment) 20 belongs is called the own group, and the group to which the own equipment 20 does not belong is called the other group. Further, the beat that the injection current injected by the own equipment 20 generates is called the other equipment, and the beat of the voltage or current generated by the total of the injection current injected by the distributed power source possessing equipment 20 belonging to the other group is called the other group beat.

FIG. 3 shows an example of waveforms of the first set of currents I _11a and I _12a and their combined current IC _1a (= I _11a + I _12a ). In the combined current IC _1a , a beat BT _1a indicated by an envelope is generated.

FIG. 4 shows another example of the waveforms of the first set of currents I _11b and I _12b and their combined current IC _1b (= I _11b + I _12b ). The current I _11b and the current I _11a shown in FIG. 3 have the same frequency but a phase difference of 180 degrees. The relationship between the current I _12b and the current I _12a is the same. This shows an example when the phase difference is the largest.

In the combined current IC _1b , a beat BT _1b indicated by an envelope is generated. Although the beat BT _1b and the beat BT _1a shown in FIG. 3 are synchronized with each other, as can be seen from a careful observation, the synthesized current IC _1b and the synthesized current IC _1a shown in FIG. Different. This is due to the phase difference between the set of currents I _11a and I _{12a and} the set of currents I _11b and I _12b (these may be referred to as component currents). When two combined currents IC _1a and IC _1b having such a phase difference of 180 degrees are combined (added) to each other, the combined current becomes 0 and disappears.

  As can be seen from the above example, even if the phase difference between component currents is not as extreme as 180 degrees, there may be a phase difference between component currents of the same frequency even if the two beats are synchronized with each other. In this case, even if the currents are combined, the component currents having the same frequency are not simply added.

  That is, the following two conditions are satisfied in order for a plurality of currents of the same frequency injected from a plurality of distributed power holding facilities 20 in the group to be simply added synchronously with a phase difference of substantially 0 degrees. There is a need.

Condition 1: The own equipment beat and other group beats are synchronized. For example, the phase difference between the own equipment beat phase and the other group beat phase is 0 degree.
Condition 2: The phase of each current of the current set constituting the injection current injected by the own equipment 20 is in a fixed phase relationship common to the own equipment beat within the same group. For example, a constant phase (for example, 0 degree) in which the phases of the currents in the current group are common within the same group at the time when the equipment is belly (that is, when the phase of the own equipment is 0 degrees). Be in The constant phase common in the same group is a coincidence phase θ _e described later.

  In other words, in the same group, that is, from the viewpoint of a certain (arbitrary) distributed power supply facility 20, it is in the own group.

The synchronous control device 50 shown in FIG. 2 performs control that satisfies the above two conditions. That is, the synchronous control device 50 makes the phase of each current of the current set constituting the injection current I _inj injected by the current injection device 40 of the own facility 20 the same as the phase of the own facility beat that causes the injection current. This is a voltage beat generated by the total of the injection current I _inj injected by the current injection device 40 of the distributed power supply facility 20 belonging to the other group while maintaining the common phase relationship common within the group and the own equipment beat. Control to synchronize with other group beats.

  Details of the principle of control by the synchronization control device 50 and an example of the configuration of the synchronization control device 50 will be described in detail later.

FIG. 5 shows an example in which the own equipment beat BT ₁ is not synchronized with another group beat BT ₂ . There is a phase difference dθ between the two beats. That's why the own equipment beat BT ₁ is delayed.

FIG. 6 shows an example in which the synchronization control device 50 synchronizes the own equipment beat BT ₁ with another group beat BT ₂ . At time t ₃ , both beats coincide and synchronize, and thereafter the synchronization state is maintained. The synchronization control device 50 can perform such beat synchronization control (control satisfying the condition 1). Furthermore, according to the synchronization control device 50, the condition 2 can be satisfied in this synchronization state.

Therefore, according to the isolated operation detection system according to the present invention, the _same is _achieved by synchronizing the beat generated by the injected current I _{inj of} the own facility 20 and the beat generated by the injected current I _inj of the other group. It is possible to synchronize a plurality of injected currents of the same frequency injected into the distribution line 10 from a plurality of distributed power source possessing facilities 20 belonging to the group with a phase difference of substantially 0 degrees. Therefore, there is no need to use a conventional synchronization signal line or an external synchronization signal source.

  In addition, by synchronizing a plurality of injection currents as described above, even if the injection current injected from the current injection device 40 of each distributed power supply facility 20 is small, those currents are added, so the same group as a whole As a result, a large injection current can then be injected into the lead-in wire 16 and thus into the distribution line 10. As a result, the capacity of the current injection device 40 constituting each distributed power supply facility 20 can be reduced. And since it becomes possible to generate the voltage with a large injection frequency in the distribution line 10 with a big injection current, the precision of the independent operation detection by each independent operation monitoring apparatus 30 can be raised. This effect increases as the number of the distributed power supply facilities 20 belonging to the same group increases. That is, when the distributed power supply facility 20 is connected to the distribution line 10 with high density, a greater effect is exhibited.

(3) Detailed Description of Principle of Control by Synchronization Control Device 50 FIGS. 11 to 13 show examples of the configuration of the synchronization control device 50, respectively. Prior to the description, the principle of control by the synchronization control device 50 will be described in detail. In the following description, the current of the first set of frequencies is taken as an example, but the same applies to the current of the second set of frequencies.

  In the following description, when it is necessary to represent a physical quantity that changes with time (that is, changes with time t), (t) that represents it is attached to each code. However, in the reference numerals in the drawings, in order to simplify the illustration, (t) and the reference numerals indicating the vector quantities are omitted.

(3-1) Expression of Two Current Phases θ ₁₁ (t) and θ ₁₂ (t) by Phase Match Time _Te and Match Phase θ _e First, the first set of currents I ₁₁ (t) and I ₁₂ (t ) Phase θ ₁₁ (t), θ ₁₂ (t) and Δθ _inj (t) (= θ ₁₂ (t) −θ ₁₁ (t), which is referred to as a self- _grown phase).

The first set of currents I ₁₁ (t) and I ₁₂ (t) are expressed as vector quantities as follows: Here, ω ₁₁ and ω ₁₂ represent the set frequencies f ₁₁ and f ₁₂ as angular frequencies ω ₁₁ (= 2πf ₁₁ ) and ω ₁₂ (= 2πf ₁₂ ), respectively. Is a fixed value that does not change.

In general, φ ₁ and φ ₂ are used as the initial phase (the third equations from the left in Equations 4 and 5). Here, the own equipment of the phases θ ₁₁ (t) and θ ₁₂ (t) is used. In order to clarify the relationship to the beat phase Δθ _inj (t), the initial phases φ ₁ and φ ₂ of the currents I ₁₁ (t) and I ₁₂ (t) (both vector quantities; the same applies hereinafter) are set to a common time (time delay). or advance) using T _e and common phase theta _e, re expressed (number 4, the rightmost formula 5). The relationship between T _e and θ _e and φ ₁ and φ ₂ is as follows.

[Equation 6]
T _e = (φ ₂ −φ ₁ ) / (ω ₁₁ −ω ₁₂ )

[Equation 7]
θ _e = (ω ₁₁・ φ ₂ −ω ₁₂・ φ ₁ ) / (ω ₁₁ −ω ₁₂ )

Using the time T _e and the phase θ _e , the phase Δθ _inj (t) of the own equipment beat is expressed as follows. First, when taking the quotient of both currents I ₁₁ (t) and I ₁₂ (t), the following equation is obtained.

Therefore, since the deviation angle of the quotient is the phase difference between the currents I ₁₁ (t) and I ₁₂ (t), that is, the phase Δθ _inj (t) of the own equipment, it is given by the following equation. Further, the phase θ _e becomes 0 and disappears.

[Equation 9]
Δθ _inj (t) = θ ₁₂ (t) −θ ₁₁ (t) = (ω ₁₂ −ω ₁₁ ) (t−T _e )

From Equation 9, the meaning of time T _e and phase θ _e is as follows.
T _e : Time when the phase of Δθ _inj (t) becomes 0 degree (that is, the time when the phases of the currents I ₁₁ (t) and I ₁₂ (t) match. Therefore, this is called the phase matching time).
θ _e: Δθ _inj (t) is 0 ° to become time current I ₁₁ at (phase matching time) T _e (t), I ₁₂ the (t) phase (i.e., current I ₁₁ (t) and I ₁₂ ( The phase when the phases of t) coincide, so this is called the coincidence phase).

When the current I ₁₁ (t) and I ₁₂ (t) are considered with respect to the beat BT _{1 obtained} by combining the currents I ₁₁ (t) and I ₁₂ (t) using the phase coincidence time _Te and the coincidence phase θ _e , FIG. 3 shows an example in which the coincidence phase θ _e is 0 degree and FIG. 4 is a simulation example in which the coincidence phase θ _e is 180 degrees, while the phase coincidence time _Te is common. As described above in both figures, even if the phase matching time _Te is common (matches each other), if the matching phase θ _e is different, currents of the same frequency are not synchronized and are not simply added. If the coincidence phase θ _e is different by 180 degrees, it disappears when added.

(3-2) Reason for making the coincidence phase θ _e common among the plurality of distributed power supply facilities 20 in the own group The synchronization of currents of the same frequency in the own group is not the beat itself but the first set of the above The relationship between the phase θ ₁₁ (t), θ ₁₂ (t) of each current and the phase Δθ _inj (t) of the own equipment is summarized below. This is because the present invention focuses not only on beats but also on the phase of two signals (current and voltage) that generate beats, considering further from there.

The phase _{θ 11 (t), θ 12} (t) is matched number 4, number 5, the number 9, the phase matching time T _e match phase theta _e, or the own equipment beat phase Δθ _inj (t) Using the phase θ _e , it can be expressed as:

[Equation 10]
θ ₁₁ (t) = ω ₁₁ (t−T _e ) + θ _e = {ω ₁₁ / (ω ₁₂ −ω ₁₁ )} · Δθ _inj (t) + θ _e

[Equation 11]
θ ₁₂ (t) = ω ₁₂ (t−T _e ) + θ _e = {ω ₁₂ / (ω ₁₂ −ω ₁₁ )} · Δθ _inj (t) + θ _e

According to _Equations 10 and 11, the phases θ ₁₁ (t) and θ ₁₂ (t) are related to the currents I ₁₁ (t) and I ₁₂ (t) in relation to the phase Δθ _inj (t) of the own equipment. it can be seen that classification by matching the phase theta _e of (grouping). Then, the group only if the same (i.e. matched phase theta _e are the same), current between the same frequencies of the first set within it can be seen that are synchronized (simple addition).

  This is shown in the simulated figures. 7 to 10, FIG. 15B, FIG. 16B, and FIG. 17B, the vertical lines connecting the 360 degree phase point and the 0 degree point parallel to the vertical axis are shown. This is due to the convenience of simulation software, and since the phase is 360 ° = 0 °, it is more accurate to consider that the vertical line is not present.

FIG. 7 shows an example of the phases θ _11a (t) and θ _12a (t) of the respective currents when the coincidence phase θ _e is 0 degree and the phase difference (that is, the phase of the beat of the own equipment) Δθ _inja (t). FIG. 8 shows an example of the phases θ _11b (t) and θ _12b (t) of each current when the coincidence phase θ _e is 180 degrees and its phase difference (that is, the phase of the beat of its own equipment) Δθ _injb (t). Show. However, in both figures, the phase matching time _Te is common (same) to each other.

As shown in FIG. 7, FIG. 8, if the phase matching time T _e is the same, even if different match phase theta _e, self facility beat phase Δθ _inj (t) are matched with each other in both figures. That is, they are synchronized.

However, as shown in FIG. 9, although the frequencies of both currents are the same, the phase θ _11a (t) of the current whose coincidence phase θ _e is 0 degrees is related to the beat phase Δθ _inj (t). The coincidence phase θ _e does not coincide with the phase θ _11b (t) of the current of 180 degrees. Although not shown, the phases θ _12a (t) and θ _12b (t) do not match each other. That is, the currents of the same frequency are not synchronized.

On the other hand, if the coincidence phase θ _e is all common within the own group (for example, at 0 degree), the phases θ _11a (t) and θ _11b (t) are as shown in FIG. Match each other. Although not shown, the phases θ _12a (t) and θ _12b (t) also coincide with each other. That is, currents having the same frequency are synchronized with each other in phase.

Although the above has described the two distributed power supply facilities 20 in the same group, the same applies to the case of more than that. In other words, it is important to make the coincidence phase θ _e common in a plurality of distributed power supply facilities 20 in the same group. This can be said for the first group as well as for the second group. However, the coincidence phase θ _e does not have to be common between the first group and the second group. What is necessary is just to be common within the same group.

Moreover, as can be seen from Equation 9, by controlling the phase matching time T _e, it is possible to control the self equipment beat phase Δθ _inj (t). Therefore, the own equipment beat and the other group beat can be synchronized by matching the own equipment beat phase Δθ _inj (t) with the other group beat phase Δθ _m (t) (how to obtain this will be described later). it can.

Therefore, while maintaining that you commonly matching phase theta _e in the same group as (a) above, the self equipment beat by controlling the phase matching time T _e in (b) each distributed power held equipment 20 By synchronizing with other group beats, multiple injection currents of the same frequency can be synchronized with a phase of 0 degrees. Therefore, there is no need to use a conventional synchronization signal line or an external synchronization signal source.

  The present invention is based on such a concept.

(3-3) the phase [Delta] [theta] _inj (t) Description of the own equipment beat case of changing the phase of the injected current at the beat synchronization process, to go to target a different group beat phase [Delta] [theta] _m (t) is The phases θ ₁₁ (t) and θ ₁₂ (t) of the currents I ₁₁ (t) and I ₁₂ (t) forming the set are respectively set to the set angular frequencies ω ₁₁ and ω ₁₂ (which are as described above). It is necessary to change temporarily (transiently) from a state of constant increase due to a fixed value that is not changed with time. In order to consider the currents I ₁₁ (t) and I ₁₂ (t) in the changing process, the equations (4) and (5) are changed as follows.

However, the phases φ ₁ (t) and φ ₂ (t) are expressed by the following equations.

[Formula 14]
φ ₁ (t) = dθ ₁₁ (t) + φ ₁
φ ₂ (t) = dθ ₁₂ (t) + φ ₂

The phase φ ₁ (t) is derived as follows (the same applies to the phase φ ₂ (t)).

The phase θ ₁₁ (t) can be expressed by the following equation, where dθ ₁₁ (t) is the amount of change. From the relationship between the second row and the third row in the following equation, φ ₁ (t) shown in the first row of Equation 14 is derived.

[Equation 15]
θ ₁₁ (t) = {ω ₁₁ · t + dθ ₁₁ (t)} + φ ₁
= Ω ₁₁ · t + {dθ ₁₁ (t) + φ ₁ }
= Ω ₁₁・ t + φ ₁ (t)

Further, since the phases φ ₁ and φ ₂ become the phases φ ₁ (t) and φ ₂ (t) that change with time as described above, the phase matching time T _e and the matching phase θ _e are also expressed here. Similarly, it is represented by T _e (t) and θ _e (t) as changing with time. That is the rightmost expression of the above equations (12) and (13).

  As a result, the number 6 becomes the next number 16, the number 7 becomes the next number 17, the number 8 becomes the next number 18, the number 9 becomes the next number 19, the number 10 becomes the next number 20, the number 11 is changed to the following Expression 21, respectively.

[Equation 16]
T _e = {φ ₂ (t) −φ ₁ (t)} / (ω ₁₁ −ω ₁₂ )
= {Φ ₂ −φ ₁ + dθ ₁₂ (t) −dθ ₁₁ (t)} / (ω ₁₁ −ω ₁₂ )

[Equation 17]
θ _e (t) = {ω ₁₁ · φ ₂ (t) −ω ₁₂ · φ ₁ (t)} / (ω ₁₁ −ω ₁₂ )
= {Ω ₁₁ · φ ₂ −ω ₁₂ · φ ₁ + ω ₁₁ · dθ ₁₂ (t) −ω ₁₂ · dθ ₁₁ (t)} / (ω ₁₁ −ω ₁₂ )

[Equation 19]
Δθ _inj (t) = θ ₁₂ (t) −θ ₁₁ (t) = (ω ₁₂ −ω ₁₁ ) (t−T _e (t))

[Equation 20]
θ ₁₁ (t) = ω ₁₁ (t−T _e (t)) + θ _e (t) = {ω ₁₁ / (ω ₁₂ −ω ₁₁ )} · Δθ _inj (t) + θ _e (t)

[Equation 21]
θ ₁₂ (t) = ω ₁₂ (t−T _e (t)) + θ _e (t) = {ω ₁₂ / (ω ₁₂ −ω ₁₁ )} · Δθ _inj (t) + θ _e (t)

(3-4) Relationship between keeping the coincidence phase θ _e (t) at a fixed value and the amount of change in the phases θ ₁₁ (t) and θ ₁₂ (t) From the above equation 17, the coincidence phase θ _e (t) Is a fixed value (does not change over time). The amount of change in the coincidence phase θ _e (t) when the minute time Δt has passed is expressed by the following equation using the time variation term in the second row of Equation 17.

[Equation 22]
θ _e (t + Δt) −θ _e (t)
= {Ω ₁₁ · dθ ₁₂ (t + Δt) −ω ₁₂ · dθ ₁₁ (t + Δt)} / (ω ₁₁ −ω ₁₂ ) − {ω ₁₁ · dθ ₁₂ (t) −ω ₁₂ · dθ ₁₁ (t)} / ( ω ₁₁ −ω ₁₂ )
= {(Ω ₁₁ (dθ ₁₂ (t + Δt) −dθ ₁₂ (t)) − ω ₁₂ (dθ ₁₁ (t + Δt) −dθ ₁₁ (t))} / (ω ₁₁ −ω ₁₂ )

From the above Equation 22, the sufficient condition for the coincidence phase θ _e (t) to be a fixed value (does not change) is expressed by the following equation (the following equation should be satisfied).

[Equation 23]
{Ω ₁₁ (dθ ₁₂ (t + Δt) −dθ ₁₂ (t)} − ω ₁₂ {dθ ₁₁ (t + Δt) −dθ ₁₁ (t)} = 0

  That is, it turns out that it is following Formula.

[Equation 24]
{Dθ ₁₁ (t + Δt) −dθ ₁₁ (t)} / {dθ ₁₂ (t + Δt) −dθ ₁₂ (t)} = ω ₁₁ / ω ₁₂

Here, {dθ ₁₁ (t + Δt) −dθ ₁₁ (t)}, {dθ ₁₂ (t + Δt) −dθ ₁₂ (t)} (which is referred to as (A)) are currents I ₁₁ (t), I ₁₂ This is the phase change amount for the portion changed for control from the phase change amounts ω ₁₁ · Δt and ω ₁₂ · Δt (this is referred to as (A)) due to the originally set angular frequency of (t).

Accordingly, the total (total) phase change amount from the time t to the time (t + Δt) of the currents I ₁₁ (t) and I ₁₂ (t) obtained by adding the phase change amounts (a) and (b) to each other. Are Δθ ₁₁ and Δθ ₁₂ , the following equations are obtained.

[Equation 25]
Δθ ₁₁ = ω ₁₁ · Δt + {dθ ₁₁ (t + Δt) −dθ ₁₁ (t)}

[Equation 26]
Δθ ₁₂ = ω ₁₂ · Δt + {dθ ₁₁ (t + Δt) −dθ ₁₁ (t)}

From Equations 24 to 26, the sufficient condition that the coincidence phase θ _e (t) is a fixed value (does not change) is as follows.

[Equation 27]
Δθ ₁₁ / Δθ ₁₂ = ω ₁₁ / ω ₁₂

From the above, the phases θ ₁₁ (t) and θ ₁₂ (t) of the currents I ₁₁ (t) and I ₁₂ (t) and the ratio between the phase variations Δθ ₁₁ and Δθ ₁₂ are set to the set angular frequency. The coincidence phase θ _e (t) is changed to a fixed value θ _e (not attached with (t) because it does not change with time) while maintaining the same ratio as the ratio between ω ₁₁ and ω _12. It can be seen that this is a sufficient condition. ... Conclusion A

Conversely, if the coincidence phase θ _e is a fixed value, the ratio between the phase changes of the currents I ₁₁ (t) and I ₁₂ (t) is the ratio between the set angular frequencies ω ₁₁ and ω _12. This is shown below.

The phase change amounts from time t to time (t + Δt) are denoted by Δθ ₁₁ and Δθ ₁₂ . Since the coincidence phase θ _e and the equations 20 and 21 are fixed values, the following equation is obtained.

[Equation 28]
θ ₁₁ (t) = ω ₁₁ · (t−T _e (t)) + θ _e

[Equation 29]
θ ₁₂ (t) = ω ₁₂ · (t−T _e (t)) + θ _e

[Equation 30]
θ ₁₁ (t + Δt) = ω ₁₁ · {(t + Δt) −T _e (t + Δt)} + θ _e

[Equation 31]
θ ₁₂ (t + Δt) = ω ₁₂ · {(t + Δt) −T _e (t + Δt)} + θ _e

  From the above equations 28 to 31, the following equation is obtained.

[Formula 32]
Δθ ₁₁ = θ ₁₁ (t + Δt) −θ ₁₁ (t)
= Ω ₁₁ {Δt− (T _e (t + Δt) −T _e (t)}

[Equation 33]
Δθ ₁₂ = θ ₁₂ (t + Δt) −θ ₁₂ (t)
= Ω ₁₂ {Δt− (T _e (t + Δt) −T _e (t)}

As a result, increase / decrease control of the phases θ ₁₁ (t) and θ ₁₂ (t) is maintained while maintaining the relationship of the following equation.

[Formula 34]
Δθ ₁₁ / Δθ ₁₂ = ω ₁₁ / ω ₁₂

From the above, assuming that the coincidence phase θ _e (t) is a fixed phase θ _e and controlling only the phase coincidence time _Te (t), the currents I ₁₁ (t) and I ₁₂ (t) The phases θ ₁₁ (t) and θ ₁₂ (t) are changed while maintaining the ratio between the phase variations Δθ ₁₁ and Δθ ₁₂ at the same ratio as the ratio between the set angular frequencies ω ₁₁ and ω _12. It is a sufficient condition to make it happen. ... Conclusion B

From the above conclusion A and conclusion B (ie, equations 27 and 34), the coincidence phase θ _e is set as a fixed value, and only the phase coincidence time T _e (t) is controlled (this is called a phase coincidence time control method). And the phases θ ₁₁ (t) and θ ₁₂ (t) of the currents I ₁₁ (t) and I ₁₂ (t), and the ratio between the phase variations Δθ ₁₁ and Δθ ₁₂ is set to the set angular frequency ω. It can be said that changing while maintaining the same ratio as the ratio between ₁₁ and ω ₁₂ (this is called a phase change amount control method) is equivalent (necessary and sufficient condition). The invention described in claim 5 is described from the viewpoint of the phase matching time control method. The invention according to claim 12 is also the same. The invention described in claim 2 is described from the viewpoint of the phase change amount control system. The invention according to claim 10 is also the same.

  Although the phase change amount between the time t and the time (t + Δt) is shown in the equations 32 and 33, the phase change amount may be expressed in a differential form according to the time t, with Δt being set to 0 as much as possible. In that case, the following equation is obtained.

[Equation 35]
_{dθ 11 (t) / dt =} ω 11 · {1-dT e (t) / dt}

[Equation 36]
_{dθ 12 (t) / dt =} ω 12 · {1-dT e (t) / dt}

As is well known, since the time derivative of the phase [rad] is the angular frequency [rad / s], the left side of the equations 35 and 36 is replaced with the angular frequencies ω ₁₁ (t) and ω ₁₂ (t). Taking the ratio of both equations, the following equation is obtained.

[Equation 37]
ω ₁₁ (t) / ω ₁₂ (t) = ω ₁₁ / ω ₁₂

That is, focusing on the angular frequencies ω ₁₁ (t) and ω ₁₂ (t) instead of the phase change amount, the coincidence phase θ _e is set as a fixed value, and only the phase coincidence time T _e (t) is controlled ( Phase matching time control method) and the angular frequencies ω ₁₁ (t) and ω ₁₂ (t) of the currents I ₁₁ (t) and I ₁₂ (t) It can also be said that it is equivalent to performing increase / decrease control while keeping the ratio between the set angular frequencies ω ₁₁ and ω ₁₂ (this is called a frequency control method). The invention described in claim 3 is described from the viewpoint of this frequency control system. The invention according to claim 11 is also the same. As described above, the frequency may be expressed by an angular frequency or an order. Each is equivalent.

FIGS. 15 and 16 show the case where the frequencies f ₁₁ (t) and f ₁₂ (t) of the first currents I ₁₁ (t) and I ₁₂ (t) are increased while maintaining the frequency ratio. An example is shown. FIG. 15A shows waveforms of currents I ₁₁ (t), I ₁₂ (t) and beat BT ₁ (t) before increase, and FIG. 15B shows the phases θ ₁₁ (t) and θ ₁₂ (t ) And the phase of the beat phase Δθ _inj (t). FIG. 16A shows the waveform of each current I ₁₁ (t), I ₁₂ (t) and beat BT ₁ (t) after the increase, and FIG. 16B shows the phase θ ₁₁ (t), θ ₁₂ (t ) And the phase of the beat phase Δθ _inj (t).

As shown by points P ₃ and P ₄ in FIGS. 15B and 16B, when the beat phase Δθ _inj (t) is 0 degrees, both phases θ ₁₁ (t) and θ ₁₂ (t) are 0 with respect to each other. The degree of coincidence does not change before and after the frequency change. That is, the coincidence phase θ _e described above is kept constant at 0 degree.

As a comparative example, FIG. 17 shows the frequencies f ₁₁ (t) and f ₁₂ (t) of the first set of currents I ₁₁ (t) and I ₁₂ (t) without maintaining the frequency ratio (ie, An example in the case of increasing (without observing the condition of the frequency control method) will be shown. Before the increase, since it is the same as FIG. 15, it will be referred to. FIG. 17A shows the waveforms of each current I ₁₁ (t), I ₁₂ (t) and beat BT ₁ (t) after the increase, and FIG. 17B shows the phases θ ₁₁ (t) and θ ₁₂ (t ) And the phase of the beat phase Δθ _inj (t).

As indicated by a point P ₅ in FIG. 17B, after the frequency is increased, when the beat phase Δθ _inj (t) is 0 degree, both phases θ ₁₁ (t) and θ ₁₂ (t) are 180 degrees with respect to each other. Has changed to match. That is, the aforementioned coincidence phase θ _e has changed from 0 degrees to 180 degrees. This is because the condition of the frequency control method was not observed.

  As can be seen from the above, by using any of the phase coincidence time control method, the phase change amount control method and the frequency control method, by synchronizing the own equipment beat with the other group beat by the method, as described above, Multiple injection currents of the same frequency can be synchronized with each other at a phase of substantially 0 degrees. Therefore, there is no need to use a conventional synchronization signal line or an external synchronization signal source.

  It should be noted that any one of the three control methods (that is, the phase matching time control method, the phase change amount control method, and the frequency control method) is unified in all the synchronous control devices 50 in the same group. You may employ | adopt and may mix a some control system. If they are adopted uniformly, there are advantages such as easy design and manufacture of the synchronous control device 50. The reason why they may be mixed is that the three control methods are substantially equivalent to each other as described in detail above. Also in the relationship between the control method of the synchronous control device 50 in the own group and the control method of the synchronous control device 50 in the other group, the control method may be unified or mixed as described above.

(4) Configuration of Synchronous Control Device 50 Next, an example of the configuration of the synchronous control device 50 that performs control based on the principle described in (3) above will be described.

  FIG. 11 is a block diagram illustrating an example of the configuration of the synchronization control device. The synchronization control device 50 includes another group beat phase calculator (which corresponds to another group beat phase calculating means) 58, a current phase setter (which corresponds to current phase setting means) 70, and a beat synchronizer. (This corresponds to beat synchronization means) 88.

The other group beat phase calculator 58 is a voltage included in the voltage V _s (t) in the lead-in line 16 and is an injection frequency (hereinafter referred to as “injection frequency”) of the distributed power supply facility 20 belonging to the other group. are expressed as angular frequency) ω ₂₁ (t), the voltage V ₂₁ of the _{ω 22 (t) (t)} , by measuring V ₂₂ a (t), of the other group beat based on the voltage phase [Delta] [theta] _m (t ) Is calculated.

More specifically in this example, the other groups beat phase calculator 58, the phase calculation to calculate the voltage V ₂₁ (t), the phase theta ₂₁ of V ₂₂ (t) (t), theta ₂₂ a (t), respectively And subtracters 56 for subtracting both phases θ ₂₁ (t) and θ ₂₂ (t) to obtain another group beat phase Δθ _m (t).

The current phase setter 70 has phases θ ₁₁ (t) and θ ₁₂ (t) of the currents I ₁₁ (t) and I ₁₂ (t) of the current set constituting the injection current injected by the current injection device 40 of the own equipment. ) Of each current I ₁₁ (t), I ₁₂ (t) of the current group so that the phase Δθ _inj (t) of the own equipment is in a constant phase relation common within the same group. The phases θ ₁₁ (t) and θ ₁₂ (t) are respectively set. For example, the phases θ ₁₁ (t) and θ ₁₂ (t) of the currents I ₁₁ (t) and I ₁₂ (t) when the phase Δθ _inj (t) of the own equipment becomes 0 degrees are in common agreement. The phase θ _e (for example, 0 degree) is set.

More specifically, in this example, the current phase setter 70 is based on the set frequencies (hereinafter referred to as angular frequencies) ω ₁₁ and ω ₁₂ , and the phase functions ω ₁₁ · t, ω ₁₂ · the phase function generator 60, 62, respectively to generate t, the fixed value of the matching matches a phase setter for setting the phase theta _e (which corresponds to matching the phase setting means) 64, a phase of the matching phase theta _e Adders 66 and 68 that respectively add phases ω ₁₁ · t and ω ₁₂ · t and output phases θ ₁₁₀ (t) and θ ₁₂₀ (t) represented by the following equations, respectively.

[Equation 38]
θ ₁₁₀ (t) = ω ₁₁ · t + θ _e

[Equation 39]
θ ₁₂₀ (t) = ω ₁₂ · t + θ _e

The beat synchronizer 88 _obtains a beat phase difference dθ (t), which is a phase difference between the own equipment beat phase Δθ _inj (t) and the other group beat phase Δθ _m (t), according to the following equation: The phase coincidence time based on the phase coincidence time control method, that is, using the coincidence phase θ _e of a fixed value so that the beat phase difference dθ (t) becomes a constant value (for example, 0 degree) common in the same group. by controlling T _e only (t), the number 28, number 29 to the phase theta ₁₁ based (t), and controls the θ ₁₂ (t), and controls the own equipment beat phase Δθ _inj (t) Is.

[Equation 40]
dθ (t) = Δθ _inj (t) −Δθ _m (t)

More specifically, in this example, the beat synchronizer 88 includes a subtractor (which corresponds to the beat phase calculation means) 72 that performs the calculation of the above formula 40, and an increase / decrease rate control function r for beat synchronization control. a change ratio control function generator 74 which generates the angle of integrator 76 to output the phase matching time T _e by integrating the change rate control function r (t), the phase matching time T _e (t) Multipliers 78 and 80 for multiplying the frequencies ω ₁₁ and ω ₁₂ respectively, and signals from both multipliers 78 and 80 are subtracted from the phases θ ₁₁₀ (t) and θ ₁₂₀ (t) to obtain the equations 28 and 29. And subtracters 82 and 84 for calculating the phases θ ₁₁ (t) and θ ₁₂ (t), respectively, and the difference between the two phases θ ₁₁ (t) and θ ₁₂ (t) is calculated by the following equation. Subtractor 86 (which corresponds to own equipment beat calculation means) 86 that outputs the phase Δθ _inj (t) of And.

[Equation 41]
Δθ _inj (t) = θ ₁₂ (t) −θ ₁₁ (t) = (ω ₁₂ −ω ₁₁ ) (t−T _e (t))

Equation 41 represents the phase matching time Te in _Equation 9 as a generalized amount that varies with time. That is, Equation 41 is a generalized expression including a transient state in which the phase matching time _Te (t) changes during beat synchronization operation, and Equation 9 is the phase matching time _Te (t) after beat synchronization. Shows a steady state where the value is settled to a constant value. Equations 10 and 11 also show steady states.

The phases θ ₁₁ (t) and θ ₁₂ (t) output from the subtracters 82 and 84 are also supplied to the current injection device 40. This will be described later with reference to FIG.

Current phase setter 70, and more specifically to the matching phase setter 64, for example, those matching phase theta _e when the host equipment beat phase Δθ _inj (t) becomes 0 ° is set to 0 degrees It is. However, the coincidence phase θ _e does not necessarily have to be 0 degrees, and may be a constant value that is common within the same group as described in the section of the principle explanation of (3) above.

When the coincidence phase θ _e is set to 0 degree, the coincidence phase setting unit 64 and the adders 66 and 68 need not be provided. That is, unlike the case where the coincidence phase θ _e is set to a value other than 0 degrees, the coincidence phase setting means does not have to be provided with a special device, so that the configuration of the synchronization control device 50 can be simplified. . The same applies to the examples shown in FIGS. However, when the coincidence phase θ _e is set to 0 degrees, the coincidence phase for conceptually setting the coincidence phase θ _e to 0 degrees without providing the coincidence phase setting unit 64 and the adders 66 and 68. It can be said that there are setting means.

In this example, the beat synchronizer 88 controls the beat phase difference dθ to be 0 degree. However, the beat phase difference dθ does not necessarily have to be 0 degrees, and may be a constant value common to the same group. Even in this case, the self equipment beat phase [Delta] [theta] _inj (t) and the other group beat phase [Delta] [theta] _m (t) is because in sync. The same applies to the synchronous control device 50 shown in FIGS. 12 and 13.

The control method in the beat synchronizer 88 is such that the beat phase difference dθ (t) becomes a common constant value (for example, 0 degree) within the same group, as described in the section of the principle explanation of the above (3). In addition, the phases θ ₁₁ (t) and θ ₁₂ (t) of the currents I ₁₁ (t) and I ₁₂ (t) of the current set constituting the injection current I _inj injected by the current injection device 40 of the own equipment are By changing the ratio Δθ ₁₁ / Δθ ₁₂ between the amount of change in both phases while maintaining the ratio ω ₁₁ / ω ₁₂ between the set frequencies of both currents at the same ratio, the beat of the own equipment is changed to the other group. This is equivalent to a control method (that is, a phase change amount control method) that synchronizes with the signal.

Further, the injection current I _inj injected by the current injection device 40 of the own equipment is set according to the phase difference dθ (t) so that the beat phase difference dθ (t) becomes a common constant value in the same group. The frequencies ω ₁₁ (t) and ω ₁₂ (t) of the currents I ₁₁ (t) and I ₁₂ (t) of the constituting current set are expressed as the ratio ω ₁₁ (t) / ω ₁₂ (t) between the two frequencies. This is equivalent to a control method in which the own equipment beat is synchronized with the other group beats (that is, the frequency control method described above) while maintaining the ratio ω ₁₁ / ω ₁₂ between the set frequencies.

In the frequency increase / decrease control, the frequencies ω ₁₁ (t) and ω ₁₂ (t) are deviated from the set frequencies ω ₁₁ and ω ₁₂ , but since the deviation is slight, phase difference detection between the frequencies forming the set is performed. The impact on the can be ignored.

  The possible range of the beat phase difference dθ (t) is expressed by the following equation.

[Formula 42]
−180 ° (ie −π) <dθ (t) ≦ 180 ° (ie π)

As shown in FIG. 14, when the phase Δθ _m (t) of the other group is considered as a reference, when the beat phase difference dθ (t) is positive (0 to 180 degrees), the frequencies ω ₁₁ (t) and ω ₁₂ (T) is decreased to delay the phase Δθ _inj (t) of the own equipment, and in the case of negative (0 to −180 degrees), the frequencies ω ₁₁ (t) and ω ₁₂ (t) are increased to increase the own equipment _{Advance the} beat phase Δθ _inj (t). In the case of just −180 degrees, either positive or negative may be considered.

To explain this in more detail, the phase Δθ _m (t) of the other group and the phase Δθ _inj (t) of the own equipment change 360 degrees during the period L of the beat after completion of the coincidence control (synchronous control). To do. Considering both phases as a unit circle, the circuit makes one round during the beat period L (= 1 / Δf).

When both frequencies ω ₁₁ (t) and ω ₁₂ (t) are increased while maintaining the ratio as described above, the phase Δθ _inj (t) of the own equipment becomes larger than 360 degrees with respect to the period L of the beat. . Conversely, if it is decreased, it becomes smaller than 360 degrees. Accordingly, the time advance of the own equipment beat phase Δθ _inj (t) can be advanced or delayed with respect to the time advance of the other group beat phase Δθ _m (t), so the own equipment beat phase Δθ _inj ( t) can be matched with the phase of the other group's beat phase Δθ _m (t). That is, it can be synchronized.

After the coincidence control (synchronous control) is completed, the phase Δθ _inj (t) of the own equipment and the phase Δθ _m (t) of the other group are advanced by a certain time determined by the beat period L as described above.

The above is described with reference to the first group of distributed power supply facilities 20, but when viewed from the second group of distributed power supply facilities 20, the first group of distributed power supply facilities 20 is another group. The same control as described above is performed in the second group of distributed power supply facilities 20. Accordingly, the phase Δθ _inj (t) of the own equipment and the phase Δθ _m (t) of the other group are controlled so as to approach each other and match and synchronize.

  The increase / decrease rate control function r can be expressed by the following equation, for example. That is, r is a function of dθ (t), and if expressed accurately, r (dθ (t)). k is a coefficient.

[Equation 43]
r = k · dθ (t)

  The coefficient k may be a constant or may vary according to dθ (t). In the former case, the increase / decrease rate control function r changes linearly in proportion to the beat phase difference dθ (t). In the latter case, the increase / decrease rate control function r changes nonlinearly according to the beat phase difference dθ (t). How to set the coefficient k may be determined according to the response characteristics of the required control. An upper limit value and a lower limit value may be provided in a range of values that the increase / decrease rate control function r can take.

The integrator 76, since and outputs the by integrating the change rate control function r phase matching time T _e (t), the change ratio control function generator beat phase difference d [theta] (t) becomes 0 Even when the increase / decrease rate control function r supplied from 74 becomes 0, the value of the phase coincidence time _Te (t) immediately before that is kept and output. Therefore, even after the own equipment beat phase Δθ _inj (t) and another group beat phase Δθ _m (t) are synchronized, the synchronized state can be maintained. Time t ₃ later in FIG. 6 is in the state.

  A more specific example of the synchronization control device 50 is shown in FIG. Parts that are the same as or equivalent to those in the synchronization control device 50 shown in FIG. 11 are given the same reference numerals, and the differences from FIG. 11 will be mainly described below.

  In addition to the other group beat phase calculator 58, the coincidence phase setter 64, the subtractor 72, and the subtractor 86, the synchronization control device 50 includes a phase coincidence time generator (this is a phase coincidence time generating means). 100) and a phase generator 114 (which corresponds to phase generating means).

  The other group beat phase calculator 58 includes a filter 90, discrete Fourier transformers 92 and 94, and an arithmetic circuit 96 in this example.

The filter 90 removes the fundamental wave component of the distribution system from the voltage V _s in the lead-in line 16. It is preferable to provide such a filter 90. In such a case, the S / N ratio is increased and the voltages V ₂₁ (t) and V ₂₂ (t ₂₂ ) of the second set of injection frequencies by the discrete Fourier transformers 92 and 94 are increased. ) Can be accurately extracted.

The discrete Fourier transformers 92 and 94 receive the voltage from the filter 90, perform discrete Fourier transform on the voltages, respectively, and extract the voltages V ₂₁ (t) and V ₂₂ (t) (both vector quantities), respectively. Output. Thereby, the voltages V ₂₁ (t) and V ₂₂ (t) can be measured. The voltages V ₂₁ (t) and V ₂₂ (t) are obtained by the same frequency current included in the injected current injected from the other group of distributed power supply facilities 20 (more specifically, the current injection device 40). When they are synchronized, a large voltage is generated for the reason described above.

The arithmetic circuit 96 is the same as the quotient when the phase Δθ _inj (t) of its own equipment is expressed (see _Equations 18 and 19), and the voltages V ₂₁ (t) and V ₂₂ (t). The quotient is taken and the argument arg of the quotient is taken out to calculate the phase Δθ _m (t) of the other group beat expressed by the following equation.

  When the filter 90 is provided, a phase compensator for compensating for a phase shift caused by the filter 90 may be provided between the arithmetic circuit 96 and the subtractor 72.

  The phase coincidence time generator 100 corresponds to a combination of the increase / decrease rate control function generator 74 and the integrator 76. As the increase / decrease rate control function generator 74, here, an amplifier 98 for setting a constant k is provided.

  A clock device (which corresponds to clock means) 102 generates a signal representing time t.

  In the description of the phase generator 114, when the above equations 28 and 29 are expanded, the following equations are obtained.

[Equation 45]
θ ₁₁ (t) = ω ₁₁ · (t−T _e (t)) + θ _e
= Ω ₁₁・ t−ω ₁₁・ T _e (t) + θ _e

[Equation 46]
θ ₁₂ (t) = ω ₁₂ · (t−T _e (t)) + θ _{e
= Ω 12 · t-ω 12} · T e (t) + θ e

The phase generator 114 uses the time t, the phase coincidence time T _e (t), and the coincidence phase θ _e to express the phase θ ₁₁ (t), represented by the second row of the equation 45 and the equation 46, θ ₁₂ (t) is generated. The adders 66 and 68 and the subtracters 82 and 84 are the same as described above.

The first set of frequencies f ₁₁ and f ₁₂ are set as amplification factors of the amplifiers 104, 106, 108 and 110 in this example.

  The amplifiers 104 and 105 and the amplifiers 106 and 107 constitute a part of the phase function generators 60 and 62, respectively, and perform the following calculations.

[Equation 47]
2πf ₁₁ · t = ω ₁₁ · t
2πf ₁₂ · t = ω ₁₂ · t

  The amplifiers 108 and 109 and the amplifiers 110 and 111 correspond to the multipliers 78 and 80, respectively, and perform the following calculations.

[Formula 48]
_{2πf 11 · T e (t)} = ω 11 · T e (t)
_{2πf 12 · T e (t)} = ω 12 · T e (t)

Accordingly, the subtracters 82 and 84 output the phases θ ₁₁ (t) and θ ₁₂ (t) represented by the above equations 45 and 46, respectively. That is, the same phases θ ₁₁ (t) and θ ₁₂ (t) as in the case of FIG. 11 are output. In other words, the synchronization control device 50 and the synchronization control device 50 shown in FIG. 11 are functionally equivalent.

Instead of the phase generator 114, a phase generator 118 (which corresponds to phase generation means) that constitutes the synchronization control device 50 shown in FIG. 13 may be used. This phase generator 118 is provided with a subtractor 116 for calculating t−T _e (t) in place of the amplifiers 108 to 111 and the subtractors 82 and 84.

The phase generator 118 performs the calculation on the first row of each of the above formulas 45 and 46. Therefore, the adders 66 and 68 output the phases θ ₁₁ (t) and θ ₁₂ (t) shown in the above equations 45 and 46, respectively. That is, the synchronization control device 50 shown in FIG. 13 and the synchronization control device 50 shown in FIGS. 11 and 12 are functionally equivalent to each other.

The phase matching time T _e (t) generated by the phase matching time generator 100 and the matching phase θ _e set by the matching phase setting unit 64 are as described above.

As can be seen from FIG. 13, the phase coincidence time generator 100 is said to advance or delay the device time in each synchronization control device 50 according to the phase coincidence time _Te (t) generated therefrom. You can also

  The isolated operation monitoring device 30, the current injection device 40, and the synchronous control device 50 belonging to the first group and those belonging to the second group have the same configuration. However, the frequency group of the injection current and the frequency group of the measurement voltage are different as described above (for example, see Table 1).

  The above formulas 45, 46, etc. describe the injection frequency of the distributed power source possessing equipment 20 belonging to the first group, but the above also applies to the distributed power source possessing equipment 20 belonging to the second group except that the frequency is different. The same control is performed.

  The above formulas 45 and 46 are expressed by the following formulas common to both groups. This is the same as Equation 1 above.

[Equation 49]
θ _a (t) = ω _a (t−T _e (t)) + θ _e
θ _b (t) = ω _b (t−T _e (t)) + θ _e

The phases θ _a (t), θ _b (t), and angular frequencies ω _a , ω _b in the above equation 49 are set to θ in the current injection device 40 and the synchronous control device 50 of the distributed power supply facility 20 belonging to the first group. ₁₁ (t), θ ₁₂ (t), ω ₁₁ , ω ₁₂ may be read. In the current injection device 40 and the synchronous control device 50 of the distributed power supply facility 20 belonging to the second group, θ ₂₁ (t), It may be read as θ ₂₂ (t), ω ₂₁ , ω ₂₂ . The control after the replacement is as described above. The same applies to the current injection device 40 shown in FIG.

  One of the three configuration examples of the synchronous control device 50 shown in FIGS. 11 to 13 is used for the same reason as described in the above three control methods in the section of the principle explanation of (3). One configuration may be unified and adopted in the same group, or a plurality of configurations may be mixed. If they are adopted uniformly, there are advantages such as easy design and manufacture of the synchronous control device 50. The reason why they may be mixed is that, as described above, the above three configuration examples are based on substantially equivalent control methods. In the relationship between the configuration of the synchronization control device 50 in the own group and the configuration of the synchronization control device 50 in the other group, the configuration may be unified or mixed as described above.

(5) Configuration of Current Injection Device 40 An example of the configuration of the current injection device 40 is shown in FIG.

This current injection device 40 is in the distributed power supply facility 20 belonging to the first group, and uses the two phases θ ₁₁ (t) and θ ₁₂ (t) supplied from the synchronous control device 50. Injection signal generators 42 and 44 for generating two sine wave AC signals S ₁₁ (t) and S ₁₂ (t) having the phases θ ₁₁ (t) and θ ₁₂ (t), respectively, and both sine wave ACs An adder 46 that adds the signals S ₁₁ (t) and S ₁₂ (t) to each other to produce an injection signal S _inj (t) (= S ₁₁ (t) + S ₁₂ (t)); An injection current generator (which corresponds to injection current forming means) 48 for forming the injection current I _inj using the injection signal S _inj (t) is provided. Therefore, the injection current I _inj includes the two currents I ₁₁ (t) and I ₁₂ (t) forming the above set. In this example, the injection signal generators 42 and 44 and the adder 46 constitute injection signal generation means.

The sine wave AC signals S ₁₁ (t) and S ₁₂ (t) are expressed by the following equations. S _11p and S _12p are amplitude peak values, respectively.

[Equation 50]
S ₁₁ (t) = S _11p · sin θ ₁₁ (t)
S ₁₂ (t) = S _12p · sin θ ₁₂ (t)

The above currents I ₁₁ (t) and I ₁₂ (t) are expressed by mathematical formulas as follows. I _11p and I _12p are peak values of amplitude, respectively, and these may be set as desired. It is practical that the peak values I _11p and I _12p are substantially equal to each other, but they need not be substantially equal. In the present invention, as described in the control principle (3) above, the phase of the beat due to the current at the injection frequency is important, and if the beat occurs, the amplitude is not so important.

[Formula 51]
I ₁₁ (t) = I _11p · sin θ ₁₁ (t)
I ₁₂ (t) = I _12p · sin θ ₁₂ (t)

The injection current former 48 is, for example, an amplifier that amplifies the injection signal from the adder 46. Or it is an inverter (for example, PWM inverter) which uses the injection signal S _inj (t) from the adder 46 as a signal wave of the modulation circuit.

The injection signal generating means may generate an injection signal including the two sine wave AC signals S ₁₁ (t) and S ₁₂ (t). For example, an injection signal obtained by adding another signal S _x (t) to both sine wave AC signals S ₁₁ (t) and S ₁₂ (t), for example, a square wave injection signal S _inj (t) may be generated. good. This is because the other signal S _x (t) can be removed by a filter or the like at the time of measurement, and the voltage due to the injection current generated by the sine wave AC signals S ₁₁ (t) and S ₁₂ (t) can be extracted. .

  The current injection device 40 in the distributed power supply facility 20 belonging to the second group also has the same configuration as the device shown in FIG. 20, for example.

(6) Simulation Results of Beat Phase Difference dθ (t), etc. Using the synchronization control device 50 shown in FIG. 12 above, the own equipment beat phase Δθ _inj (t) is changed to another group beat phase Δθ _m (t). The result of the simulation of the synchronized control will be described.

In the simulation, two current injection devices 40 and a synchronization control device 50 belonging to the first group and two current injection devices 40 and a synchronization control device 50 belonging to the second group were used. The frequency combinations shown in Table 1 were f ₁₁ = 132 Hz, f ₁₂ = 144 Hz, f ₂₁ = 156 Hz, and f ₂₂ = 168 Hz. Further, background noise was injected from a random number generator into a line simulating the distribution line 10. This is to bring it closer to the actual situation of the power distribution system.

The change of the beat phase difference dθ (t) is shown in FIG. 18, and the change of the phase difference Dθ ₁ (t) between two injected currents of the same frequency (specifically f ₁₁ ) in the first group is shown in FIG. Show.

As shown in FIG. 19, the phase difference Dθ ₁ (t) is assumed to be shifted by 180 degrees when the simulation is started (this corresponds to when the current injection device 40 and the synchronous control device 50 are turned on). That is, the phase difference was maximized.

As shown in FIG. 18, for a while after the start of the simulation, the background noise is larger than the voltage generated by the injection current of the second group (the other group), so the beat phase difference dθ (t) is not stable and the maximum However, the beat phase difference dθ (t) rapidly decreased from around 0.5 seconds and became 0 degrees in about 3.5 seconds. That is, the own equipment beat was synchronized with other groups. This is because, after a lapse of time after the start of the simulation, the phase of the voltage generated by the injection current of the second group is gradually aligned by the control by the synchronous control device 50 described above, and the phase Δθ _m (t) of the other group beats. The beat phase difference dθ (t) gradually becomes clear, and the beat phase difference dθ (t) becomes 0 in the first group (own group) by the control by the synchronous control device 50 described above. This is a result controlled to a degree.

Along with the above attenuation of the beat phase difference dθ (t), as shown in FIG. 19, the phase difference Dθ ₁ (t) between the two injected currents of the same frequency in the first group also gradually decreases, and the beat position At about 3.5 seconds when the phase difference dθ (t) is 0 degrees and the two beats are synchronized, the phase difference Dθ ₁ (t) is also 0 degrees. The phase difference Dθ ₂ (t) between two other injected currents having the same frequency (of the frequency f ₁₂ ) in the first group is also about 3 as in the case of the phase difference Dθ ₁ (t), although not shown. 0 degree at 5 seconds.

  That is, by synchronizing both beats according to the present invention, it was confirmed that two injection currents of the same frequency of the own group can be synchronized with a phase difference of 0 degree.

(7) Configuration of Isolated Operation Monitoring Device 30 An example of the configuration of the isolated operation monitoring device 30 is shown in FIG.

  The isolated operation monitoring device 30 includes discrete Fourier transformers 32 and 33, absolute value calculators 34 and 35, determiners 36 and 37, an AND circuit 38, and a duration determiner 39.

The discrete Fourier transformers 32 and 33 have the same functions as the discrete Fourier transformers 92 and 94 shown in FIG. Accordingly, the discrete Fourier transformers 32 and 33 may be omitted, and the discrete Fourier transformers 92 and 94 shown in FIG. 12 may be shared by the other group beat phase calculator 58 and the isolated operation monitoring apparatus 30. . In other words, the injection frequency voltages V ₂₁ (t) and V ₂₂ (t) output from the discrete Fourier transformers 92 and 94 shown in FIG. 12 may be supplied to the absolute value calculators 34 and 35, respectively. . In such a case, the configuration can be simplified. It is therefore more practical.

The absolute value calculators 34 and 35 calculate and output absolute values | V ₂₁ (t) | and | V ₂₂ (t) | of the voltages V ₂₁ (t) and V ₂₂ (t), respectively. is there.

The determiners 36 and 37 compare the absolute values | V ₂₁ (t) | and | V ₂₂ (t) | with predetermined determination values J ₁ and J ₂ , respectively, to obtain an absolute value | V ₂₁ (t). When |, | V ₂₂ (t) | becomes equal to or greater than the determination values J ₁ , J ₂ , the detection signals S ₁ , S ₂ are output, respectively. The determination values J ₁ and J ₂ are, for example, absolute values | V ₂₁ (t) |, | V ₂₂ (t in a state where no single operation has occurred, that is, in a connected operation (in other words, when the system is healthy). ) | Is set to about twice each.

Both determination values J ₁ and J ₂ may be the same value or different from each other according to the determination frequency or the like.

The AND circuit 38 takes the logical product of both detection signals S ₁ and S ₂ and outputs the detection signal S ₃ when both signals S ₁ and S ₂ are output.

Rather than outputting the detection signal S ₃ as an isolated operation detection signal as it is from the isolated operation monitoring device 30, the detection signal S ₃ is continued for a predetermined duration confirmation time T ₀ by the duration determination unit 39 as in this example. preferably, so as to output the isolated operation detecting signal S ₄ when continuing to determine that they are. By doing so, it is possible to prevent erroneous detection due to instantaneous fluctuations of the voltage V _s or the like due to some cause other than the single operation. The continuation confirmation time T ₀ may be set to, for example, about 0.05 seconds because the isolated operation detection is delayed as the duration confirmation time T ₀ is lengthened. In this example, by the output of the isolated operation detection signal S ₄ , the isolated operation monitoring device 30 finally detects that the distributed power supply 26 in the distributed power supply facility 20 in which the isolated operation monitoring device 30 is provided has been operated independently. It will be done.

To do disconnecting the islanding detection after dispersing power source 26 by the independent operation monitoring device 30, for example, as in the example shown in FIG. 2, it may be opened switch 22 by the independent operation detecting signal S _4, it the inverter gated block to the inverter of the power conditioner 24 by the independent operation detecting signal S ₄ may be stopped, it may be used in combination of both. Since the distributed power supply with low-voltage interconnection reverse power flow uses an inverter at the output section (only this method is permitted by the electric equipment technical standards), a gate block for this inverter can be used. Since the gate block is performed instantaneously, when the gate block is used, the disconnection time after the isolated operation detection by the isolated operation monitoring device 30 can be ignored.

In addition, like the isolated operation monitoring device 30 of this example, the voltage of both injection frequencies of a set of injection frequencies is measured, and the detection signal S ₃ and the isolated operation detection signal are detected under the AND condition of the detection signals S ₁ and S _2. When outputs a S _4, although preferably it is possible to more reliably prevent carefully performed by erroneously detected islanding detection, performs independent operation detecting by measuring only the voltage of one of the injection frequency You may do it.

  FIG. 22 shows an example of the result of performing a simulation of isolated operation detection using the simulation model simulating the power distribution system shown in FIG.

  In this simulation, it is assumed that there is a system power supply with a short-circuit capacity of 100 MVA on the upper system 2 side of 6.6 kV, and the impedance of the substation transformer 6 based on 6.6 kV and 10 MVA. ) Is j8%, the impedance of the distribution line 10 is 3 × (6% + j8%), and the load 12 has an effective capacity of 1 MW and a reactive capacity of 0.5 MVar. In addition, in order to continue the isolated operation state after the isolated operation is detected by the isolated operation monitoring device 30, a 1 MW large distributed power source is connected to the distribution line 10. Then, one distributed power source possessing facility 20 belonging to the first group was connected to the A phase B phase of the three-phase distribution line 10, and one distributed power source possessing facility 20 belonging to the second group was connected to the C phase A phase. The frequencies used in the both distributed power source holding facilities 20 are as in the above example. In this simulation, no background noise is injected into the distribution line 10.

At time t ₀ 3 seconds after the start of measurement, the substation circuit breaker 8 was opened, and an independent operation was generated. The absolute value | V ₂₁ (t) | of the voltage V ₂₁ (t) becomes equal to or greater than the judgment value J ₁ at time t ₂ = 3.035 seconds, and the absolute value | V ₂₂ (t) of the voltage V ₂₂ (t) ) | Becomes equal to or greater than the judgment value J ₂ at time t ₁ = 3.025 seconds, and the islanding operation monitoring device 30 makes a judgment based on the AND condition of both, so that the islanding operation is performed at the later time t ₂ = 3.035 seconds. Was detected. The final isolated operation detection, that is, the output of the isolated operation detection signal S ₄ was performed after the continuation confirmation time T ₀ set to 0.05 seconds had elapsed.

Since the time T ₁ from the occurrence of the isolated operation to the final detected independent operation is expressed by the following equation, it can be seen that high-speed detection within 0.1 seconds could be performed.

[Formula 52]
T ₁ = (t ₂ −t ₀ ) + T ₀
= (3.035-3.000) +0.05
= 0.085 [seconds]

(8) In the case of a three-phase distribution line An example in the case of connecting a plurality of distributed power supply facilities 20 to a three-phase distribution line is shown in FIG. 23, and the equivalent circuit is shown in FIG.

  The distribution line 10 is a three-phase distribution line, and each of the distributed power supply facilities 20 is connected between one of the three lines of the three-phase distribution line 10.

  In such a case, for the reasons described below, the distributed power source holding equipment 20 connected between the first lines of the three-phase distribution line 10 and the distributed power source holding equipment 20 connected between the second lines are described above. It is preferable that the distributed power supply facility 20 belonging to the first group and connected between the third lines belong to the second group.

  The first line, the second line, and the third line are, for example, between the A phase and the B phase, between the B phase and the C phase, and between the C phase and the A phase (FIG. 23 shows an example in this case). ), Not limited to this combination.

If a plurality of distributed power supply facilities 20 belonging to the same group are connected to all three lines, the same frequency included in the injection current injected from the current injection device 40 of each distributed power supply facility 20 The currents synchronized with each other become the circulating current I _cc that circulates between the ABC phases through the current injection devices 40 without passing through the load 12, so that an injection frequency voltage is generated between the lines depending on the current. Disappear. This makes it difficult to detect an isolated operation.

  On the other hand, by dividing the plurality of distributed power source holding facilities 20 into the first group and the second group as described above, the currents of the same frequency and the same phase included in the injected current are all between the three lines. Therefore, the current can be prevented from flowing as a circulating current through the current injection device 40 between the three lines of the three-phase distribution line. Therefore, it is possible to prevent the above-described inconvenience that it becomes difficult to detect an isolated operation.

In addition, by dividing the plurality of distributed power source holding facilities 20 as described above, each isolated operation monitoring device 30 has another group of distributed power sources between lines different from the line to which the own facilities are connected. Although the voltage due to the injection current injected by the facility 20 is measured, there is no problem. For example, when a current I ₁₁ is injected between the A phase and the B phase, as shown in FIG. 24, a current of (2/3) · I ₁₁ flows through the load 12 between the A phase and the B phase. A current of (1/3) · I ₁₁ flows between the C phase and the A phase. When the impedance of each load 12 is Z _L , between the B phase and the C phase, between the C phase and the A phase, between the A phase and the B phase. This is because a half voltage is generated and can be measured.

(9) Independent operation detection device If attention is paid to the isolated operation monitoring device 30, the current injection device 40, and the synchronous control device 50 in each distributed power supply facility 20, these devices 30, 40, and 50 It can be said that it constitutes an isolated operation detection device that detects the isolated operation of the distributed power supply 26 in the system 20. In other words, it can be said that each distributed power supply facility 20 includes an isolated operation detection device having the isolated operation monitoring device 30, the current injection device 40, and the synchronous control device 50, respectively.

(10) Single operation detection device for subsequent distributed power supply facility As described above, after constructing the single operation detection system, the number of distributed power supply facilities 20 constituting the first group and / or the second group. May be changed (in the following, focusing on the increase). The required distributed power supply facility 20 may be replaced with another (for example, new) distributed power supply facility for repair or the like.

  For such an increase, replacement, etc., one of the first group and the second group of distributed power supply facilities connected to the distribution line 10 of the distribution system having the islanding detection system. If a distributed power supply facility that is a member of a group is called a subsequent distributed power supply facility, the subsequent distributed power supply facility is, for example, substantially the same configuration as the distributed power supply facility 20. good.

  Alternatively, the single operation detection device for detecting the single operation of the distributed power supply in the subsequent distributed power supply facility is used as the single operation detection for the distributed power supply facility 20 without focusing on the single operation detection device. You may make it the substantially same structure as an apparatus (refer said (9) term). The point is that it has substantially the same configuration as the isolated operation detection device for the distributed power supply facility 20 for the subsequent distributed power supply facility (more specifically, for the detection of the isolated operation of the distributed power supply, the same applies hereinafter). A single operation detection device may be provided.

  That is, (a) an injection frequency of one of the first set and the second set is set, and an injection current including a current set of the frequency is sent to the subsequent distributed power supply facility and the distribution line 10 A current injection device that injects into the distribution line 10 through the lead-in line 16 connecting the power supply line, and (b) a voltage at the lead-in line 16 for the subsequent distributed power source holding facility, the other of the first set and the second set At least one injection frequency constituting the set injection frequency is set and the voltage of the frequency is measured, and from the increase of the voltage, the distributed power source in the subsequent distributed power source holding facility has become a single operation (C) The subsequent distributed power source possession facility is called the own facility, and the group of the distributed power source possession facilities 20 of which the own facility is a member is the own group, Distributed power supply for non-members When the group of the installed facilities 20 is called another group, the phase of each current of the current set constituting the injection current injected by the current injection device for the own facility is the beat of the own facility that is the beat that the injection current generates. While maintaining the same fixed phase relationship within the same group with respect to the phase, the beat of the voltage generated by the whole of the injected current injected by the current injection device of the distributed power supply facility 20 belonging to the other group. It is only necessary to provide an isolated operation detection device including a synchronous control device that synchronizes with other group beats.

  More specifically, the current injection device shown in (a), the isolated operation monitoring device shown in (b), and the synchronous control device shown in (c) are the current injection device 40 and the isolated operation monitoring device. 30 and the synchronization control device 50 have substantially the same configuration, and each of them has substantially the same function. Therefore, for the current injection device, the isolated operation monitoring device, and the synchronous control, the above description of the current injection device 40, the isolated operation monitoring device 30 and the synchronous control device 50 is referred to, and redundant description is omitted here. .

  Incidentally, the synchronous control device shown in the above (c) is similar to the synchronous control device 50 in the three control methods (that is, the phase matching time control method, the phase change amount control method and the frequency control method). Any of these may be adopted. Further, any of the three configuration examples described with reference to FIGS. 11 to 13 for the synchronization control device 50 may be adopted.

The first set of injection frequency f ₁₁ and f ₁₂ in the current injection device for subsequent distributed power held equipment is set, the second set of injection frequency f ₂₁ and f ₂₂ are set to the independent operation monitoring device If so, the subsequent distributed power supply facility becomes a member of the first group of distributed power supply facilities. In contrast, the second set of injection frequencies f ₂₁ and f ₂₂ are set in the current injection device for the subsequent distributed power supply facility, and the first set of injection frequencies f ₁₁ and f ₁₂ are set in the isolated operation monitoring device. Is set, the succeeding distributed power supply facility becomes a member of the second group of distributed power supply facilities.

In other words, if the subsequent distributed power supply facility is to be a member of the first group of distributed power supply facilities, the current injection device for the subsequent distributed power supply facility is connected to the first set of injection frequencies f ₁₁ and f _{11. 12} and the second set of injection frequencies f ₂₁ and f ₂₂ may be set in the isolated operation monitoring device. On the other hand, if the subsequent distributed power supply facility is to be a member of the second group of distributed power supply facilities, the second set of injection frequencies f ₂₁ and f ₂₂ are added to the current injection device for the subsequent distributed power supply facility. And the first set of injection frequencies f ₁₁ and f ₁₂ may be set in the isolated operation monitoring device.

In the same manner as described above for the islanding operation monitoring device 30, the islanding operation monitoring device for the subsequent distributed power supply facility also has an injection frequency (for example, the first one) of the two injection frequencies forming the set. Taking a set as an example, may be configured to detect the isolated operation f one of the ₁₁ and f ₁₂₎ is set to measure the voltage of the injection frequency.

  According to such an isolated operation detection device, for the same reason as described in detail above for the isolated operation detection system, the beat generated by the current injection device for its own equipment is generated, Utilizing the synchronization with the beat generated by the injected current, the injected current injected from the current injection device for the own equipment into the distribution line 10 is injected by the current injection device of the distributed power supply equipment belonging to the same group. It can be synchronized with an injection current of the same frequency. Therefore, there is no need to use a conventional synchronization signal line or an external synchronization signal source.

  The control method and configuration of the synchronous control device that constitutes the subsequent isolated operation detection device shown in (c) above are the three control methods (that is, the synchronous control device 50 of the isolated operation detection system) (that is, The synchronous control device belonging to the same group for the same reason as described for the phase matching time control method, the phase change amount control method and the frequency control method) and the three configuration examples (see FIGS. 11 to 13). It may be unified within the same group together with 50 control methods and configurations, or a plurality of control methods and configurations may be mixed as different ones. Together, there are advantages such as easy design and manufacture of the synchronous control device. As described in detail above, the three control methods are substantially equivalent to each other, and the three configuration examples are based on control methods substantially equivalent to each other. Because.

  Further, as described above, the current phase setting means provided in the synchronous control device 50 of the previous isolated operation detection system sets the phase of each current in the current set to 0 degrees when the phase of the beat of the equipment is 0 degrees. When the beat synchronization means sets the phase difference between the own equipment beat phase and the other group beat phase to 0 degree, similarly, it constitutes the subsequent isolated operation detection device. The current phase setting means provided in the synchronization control device that sets the phase of each current of the current set to 0 degrees when the phase of the own equipment beat is 0 degrees. The phase difference between the beat phase and the other group beat phase is set to 0 degree. This is because, as shown in the above (c), the synchronization control device for the succeeding device maintains a constant phase relationship common within the same group and synchronizes the own equipment beat with the other group beat.

  In the above case, the current phase setting means for the succeeding device sets the phase of each current in the current set when the phase of the own equipment beats to 0 degrees, and sets it to 0 degrees. Unlike the case where the angle is set to other than 0 degrees, it is not necessary to provide a special setting means, so that the configuration of the synchronous control device for the succeeding device can be simplified.

Similarly, the phase coincidence time generation means provided in the synchronous control device 50 of the previous isolated operation detection system generates the phase coincidence time _Te (t) that makes the beat phase difference 0 degree, and coincides with it. When the phase setting means sets the coincidence phase θ _e when the phase of the beat of its own equipment becomes 0 degrees, similarly, the synchronous control apparatus constituting the subsequent isolated operation detecting apparatus is The phase coincidence time generating means provided is for generating a phase coincidence time _Te (t) that makes the beat phase difference 0 degrees, and the coincidence phase setting means is used when the phase of the own equipment beat becomes 0 degrees. comprising a matching phase theta _e in shall be set to 0 degrees. This is because, as shown in the above (c), the synchronization control device for the succeeding device maintains a constant phase relationship common within the same group and synchronizes the own equipment beat with the other group beat.

  In the above case, the coincidence phase setting means for the subsequent device sets the coincidence phase when the own equipment beat phase becomes 0 degrees, and when setting to 0 degrees, other than 0 degrees. Unlike the case of setting, it is not necessary to provide special setting means, so that the configuration of the synchronous control device for the subsequent device can be simplified.

It is a single line connection figure which shows an example of a power distribution system provided with the independent operation detection system of the distributed power source which concerns on this invention. It is a figure which shows an example of a structure of each distributed power supply equipment. It is a figure which shows an example of the waveform (A) of each electric current of a 1st group, and the waveform (B) of those synthetic currents. It is a figure which shows the other example of the waveform (A) of each electric current of a 1st group, and the waveform (B) of those synthetic currents. It is a figure which shows an example when the own equipment beat is not synchronizing with the other group beat. It is a figure which shows an example at the time of synchronizing own equipment beat with another group beat. It is a figure which shows an example of the phase of each 1st set electric current in case a coincidence phase is 0 degree | times, and its phase difference (phase of own equipment beat). It is a figure which shows an example of the phase of each 1st set electric current in case a coincidence phase is 180 degree | times, and its phase difference (phase of own equipment beat). It is a figure which shows an example of the relationship between the phase of two electric currents of the same frequency when a coincidence phase differs from each other, and the phase of a self-arrangement. It is a figure which shows an example of the relationship between the phase of two electric currents of the same frequency when a coincidence phase is mutually in agreement, and the phase of the own equipment beat. It is a block diagram which shows an example of a structure of a synchronous control apparatus. It is a block diagram which shows the other example of a structure of a synchronous control apparatus. It is a block diagram which shows the further another example of a structure of a synchronous control apparatus. It is a figure which shows the relationship between the phase of an own equipment beat, and the phase of another group beat by a unit circle. The figure which shows an example of each current and beat waveform (A) before increase, and each current and beat phase (B) when the frequency of each current of the first set is increased while maintaining the frequency ratio It is. The figure which shows an example of each current and beat waveform (A) after an increase, and each current and beat phase (B) at the time of increasing the frequency of each 1st set current, maintaining a frequency ratio It is. An example of each increased current and beat waveform (A) and each current and beat phase (B) when the frequency of each current of the first set is increased without maintaining the frequency ratio is shown. FIG. It is a figure which shows an example of the result of having simulated the change of the beat phase difference. It is a figure which shows an example of the result of having simulated the change of the phase difference between the two injection currents of the same frequency of the own group. It is a block diagram which shows an example of a structure of a current injection apparatus. It is a block diagram which shows an example of a structure of an isolated operation monitoring apparatus. It is a figure which shows an example of the result of having simulated the change of the voltage of the 2nd set of injection frequency at the time of single operation generation | occurrence | production. It is a figure which shows an example in the case of connecting a some distributed power supply equipment to a three-phase distribution line. FIG. 24 is an equivalent circuit diagram of FIG. 23.

Explanation of symbols

2 Host system 4 Substation 10 Distribution line 16 Service line 20 Distributed power supply facility 26 Distributed power supply 30 Stand-alone monitoring device 40 Current injection device 42 Injection signal generator 48 Injection current generator 50 Synchronous control device 58 Other group beat phase calculator 64 Match phase setter 70 Current phase setter 72 Subtractor (beat phase calculation means)
86 Subtractor (own equipment beat calculation means)
88 Beat synchronizer 100 Phase matching time generator 102 Clock device 114, 118 Phase generator Δθ _inj (t) Own beat phase Δθ _m (t) Other group beat phase dθ (t) Beat phase difference θ _e coincidence phase T _e (t) Phase matching time I _inj injection current f ₁₁ , f ₁₂ , f ₂₁ , f ₂₂ injection frequency

Claims (12)

A plurality of distributed power source holding facilities with distributed power sources are connected to the distribution lines of the distribution system whose distribution lines are connected to the upper system via a substation. A current injection device for injecting an injection current having an injection frequency that is different from the fundamental frequency of the distribution system into the distribution line through a lead-in line connecting the power distribution line and the distribution line, and measuring a voltage at the injection frequency in the lead-in line In the isolated operation detection system of the configuration comprising an isolated operation monitoring device that detects that the distributed power supply in the distributed power supply facility has become isolated operation from the increase in the voltage,
(A) classifying the plurality of distributed power supply facilities into two groups, a first group and a second group;
(B) Two sets of injection frequencies each consisting of two injection frequencies that generate beats, and the frequency difference between the two injection frequencies forming each set is the same in both sets and constitutes both sets The four injection frequencies use different first and second sets of injection frequencies,
(C) The current injection device of each distributed power supply facility belonging to the first group has a first set of injection frequencies set, injects an injection current including the current set of the injection frequency, and operates the distributed power supply facilities independently The monitoring device is configured to detect at least one injection frequency of the second set of injection frequencies and measure the voltage of the injection frequency to detect the islanding operation.
(D) The current injection device of each distributed power supply facility belonging to the second group has a second set of injection frequencies set, injects an injection current including the current set of the injection frequency, and operates the distributed power supply facilities independently The monitoring device is configured to detect at least one injection frequency of the first set of injection frequencies and measure the voltage of the injection frequency to detect the single operation.
(E) And each distributed power supply facility of both groups, when the group to which the own equipment belongs is called the own group and the group to which the own equipment does not belong is called the other group, the injection injected by the current injection device of the own equipment While maintaining the phase of each current of the current set constituting the current in a constant phase relationship common within the same group with respect to the phase of the own equipment beating that the injected current generates, the own equipment beat is A distributed power source characterized by comprising a synchronous control device that synchronizes with another group beat, which is a voltage beat generated by a total of injection currents injected by a current injection device of a distributed power supply facility belonging to another group Isolated operation detection system. The synchronization control device includes:
(A) A voltage included in the voltage in the lead-in line, the voltage of the injection frequency of the current injection device of the distributed power supply facility belonging to the other group is measured, and the phase of the other group beats based on the voltage Other group beat phase calculating means for calculating
(B) The phase of each current of the current set constituting the injection current injected by the current injection device of the own equipment has a constant phase relationship common to the own equipment beat phase in the same group. Current phase setting means for setting the phase of each current of the current set;
(C) A phase difference between the phase of the beat of the own equipment and the phase of the beat of the other group is obtained, and the current injection device of the own equipment injects such that the phase difference becomes a constant value common in the same group. The phase of each current of the current set constituting the injected current is changed while maintaining the ratio between the change amounts of both phases at the same ratio as the ratio between the set frequencies of both currents, The isolated operation detection system for a distributed power supply according to claim 1, further comprising beat synchronization means for synchronizing with the other group beats. The synchronization control device includes:
(A) A voltage included in the voltage in the lead-in line, the voltage of the injection frequency of the current injection device of the distributed power supply facility belonging to the other group is measured, and the phase of the other group beats based on the voltage Other group beat phase calculating means for calculating
(B) The phase of each current of the current set constituting the injection current injected by the current injection device of the own equipment has a constant phase relationship common to the own equipment beat phase in the same group. Current phase setting means for setting the phase of each current of the current set;
(C) Obtaining a phase difference between the phase of the own equipment beat and the phase of the other group beat, and depending on the phase difference so that the phase difference becomes a constant value common in the same group. The frequency of each current of the current set constituting the injection current injected by the current injection device is increased / decreased while maintaining the ratio between the two frequencies to the ratio between the set frequencies, and the own equipment beat is The isolated operation detection system for a distributed power supply according to claim 1, further comprising a beat synchronization means for synchronizing with a group beat. The current phase setting means sets the phase of each current of the current set to 0 degree when the phase of the beat of the equipment is 0 degree,
4. The isolated operation detection system for a distributed power supply according to claim 2, wherein the beat synchronization unit sets a phase difference between the phase of the own equipment beat and the other group beat phase to 0 degrees. 5. (1) The synchronous control device
(A) A voltage included in the voltage in the lead-in line, the voltage of the injection frequency of the current injection device of the distributed power supply facility belonging to the other group is measured, and the phase of the other group beats based on the voltage Other group beat phase calculating means for calculating
(B) clock means for generating a signal representing time t;
(C) The phase matching time T _e (t) ((t) is a physical quantity that varies with time, which corresponds to the following beat phase difference and makes the beat phase difference a constant value common within the same group. Phase matching time generating means for generating the same),
(D) coincidence phase setting means for setting coincidence phase θ _e which is a common fixed phase in the same group;
(E) When the set two injection frequencies forming the set of own equipment are expressed as angular frequencies and ω _a and ω _b , the time t, the phase coincidence time _Te (t) and the coincidence phase θ _e are used. Phase generating means for generating two phases θ _a (t) and θ _b (t) represented by the following equation or a mathematically equivalent equation thereof:
θ _a (t) = ω _a (t−T _e (t)) + θ _e ,
θ _b (t) = ω _b (t−T _e (t)) + θ _e
(F) Self-equipment beat phase calculation means for calculating a phase difference between the two phases θ _a (t) and θ _b (t) and calculating a phase of the own equipment beat;
(G) a beat phase difference calculating means for calculating a beat phase difference which is a phase difference between the phase of the own equipment beat and the other group beat phase;
(2) The current injection device includes:
(A) Using the two phases θ _a (t) and θ _b (t), an injection signal including two sinusoidal AC signals each having the phases θ _a (t) and θ _b (t) is generated. Injection signal generating means for
(B) The isolated operation detection system for a distributed power source according to claim 1, further comprising: an injection current forming unit configured to form the injection current using the injection signal. The phase matching time generating means, the beat phase difference are those wherein generating a phase matching time T _e (t) to 0 °,
The matching phase setting means, wherein the isolated operation detecting system of the distributed power supply according to claim 5, wherein the matching phase theta _e when the host equipment beat phase becomes 0 ° is to set to 0 degrees.   7. Each of the injection frequencies constituting the first set and the second set of injection frequencies is a non-integer multiple frequency that is greater than one time the fundamental frequency of the power distribution system. An isolated operation detection system for a distributed power source as described in 1. The distribution line is a three-phase distribution line,
Each of the distributed power holding facilities is connected between one of the three lines of the three-phase distribution line,
And the distributed power supply equipment connected between the first lines of the three-phase distribution lines and the distributed power supply equipment connected between the second lines belong to the first group, and between the third lines The system for detecting an isolated operation of a distributed power supply according to any one of claims 1 to 7, wherein a connected distributed power supply facility belongs to the second group. 9. One of the first group and the second group of distributed power supply facilities connected to a distribution line of the distribution system comprising the distributed power supply single operation detection system according to any one of claims 1 to 8. A device for detecting a single operation of a distributed power supply in a subsequent distributed power supply facility that becomes a member of
(A) An injection frequency of one of the first set and the second set is set, and an injection current including a current set of the frequency is connected to the subsequent distributed power supply facility and the distribution line A current injection device for injecting into the distribution line through a lead-in wire;
(B) A voltage in the lead-in line for the subsequent distributed power supply facility, wherein at least one injection frequency constituting the injection frequency of the other of the first set and the second set is set. A single operation monitoring device for measuring the voltage of the frequency and detecting from the increase of the voltage that the distributed power source in the subsequent distributed power source holding facility has become a single operation,
(C) The subsequent distributed power supply facility is called a self facility, the group of the distributed power supply facilities that the self facility is a member of, and the group of the distributed power supply facilities that the self facility is not a member of Is called the other group, the phase of each current of the current set constituting the injection current injected by the current injection device for the own equipment is the same as the phase of the own equipment beat that is the beat generated by the injection current. While maintaining a constant phase relationship common within the group, the other group beating is the voltage generated by the total of the injected current injected by the current injection device of the distributed power supply facility belonging to the other group. An isolated operation detection device for a distributed power source, comprising: a synchronization control device for synchronization. The synchronization control device includes:
(A) A voltage included in the voltage in the lead-in line, the voltage of the injection frequency of the current injection device of the distributed power supply facility belonging to the other group is measured, and the phase of the other group beats based on the voltage Other group beat phase calculating means for calculating
(B) The phase of each current of the current set constituting the injection current injected by the current injection device of the own equipment has a constant phase relationship common to the own equipment beat phase in the same group. Current phase setting means for setting the phase of each current of the current set;
(C) A phase difference between the phase of the beat of the own equipment and the phase of the beat of the other group is obtained, and the current injection device of the own equipment injects such that the phase difference becomes a constant value common in the same group. The phase of each current of the current set constituting the injected current is changed while maintaining the ratio between the change amounts of both phases at the same ratio as the ratio between the set frequencies of both currents, The isolated operation detection device for a distributed power supply according to claim 9, further comprising beat synchronization means for synchronizing with the other group beat. The synchronization control device includes:
(A) A voltage included in the voltage in the lead-in line, the voltage of the injection frequency of the current injection device of the distributed power supply facility belonging to the other group is measured, and the phase of the other group beats based on the voltage Other group beat phase calculating means for calculating
(B) The phase of each current of the current set constituting the injection current injected by the current injection device of the own equipment has a constant phase relationship common to the own equipment beat phase in the same group. Current phase setting means for setting the phase of each current of the current set;
(C) Obtaining a phase difference between the phase of the own equipment beat and the phase of the other group beat, and depending on the phase difference so that the phase difference becomes a constant value common in the same group. The frequency of each current of the current set constituting the injection current injected by the current injection device is increased / decreased while maintaining the ratio between the two frequencies to the ratio between the set frequencies, and the own equipment beat is 10. The isolated operation detection device for a distributed power supply according to claim 9, further comprising a beat synchronization means for synchronizing with a group beat. (1) The synchronous control device
(A) A voltage included in the voltage in the lead-in line, the voltage of the injection frequency of the current injection device of the distributed power supply facility belonging to the other group is measured, and the phase of the other group beats based on the voltage Other group beat phase calculating means for calculating
(B) clock means for generating a signal representing time t;
(C) The phase matching time T _e (t) ((t) is a physical quantity that varies with time, which corresponds to the following beat phase difference and makes the beat phase difference a constant value common within the same group. Phase matching time generating means for generating the same),
(D) coincidence phase setting means for setting coincidence phase θ _e which is a common fixed phase in the same group;
(E) When the set two injection frequencies forming the set of own equipment are expressed as angular frequencies and ω _a and ω _b , the time t, the phase coincidence time _Te (t) and the coincidence phase θ _e are used. Phase generating means for generating two phases θ _a (t) and θ _b (t) represented by the following equation or a mathematically equivalent equation thereof:
θ _a (t) = ω _a (t−T _e (t)) + θ _e ,
θ _b (t) = ω _b (t−T _e (t)) + θ _e
(F) Self-equipment beat phase calculation means for calculating a phase difference between the two phases θ _a (t) and θ _b (t) and calculating a phase of the own equipment beat;
(G) a beat phase difference calculating means for calculating a beat phase difference which is a phase difference between the phase of the own equipment beat and the other group beat phase;
(2) The current injection device includes:
(A) Using the two phases θ _a (t) and θ _b (t), an injection signal including two sinusoidal AC signals each having the phases θ _a (t) and θ _b (t) is generated. Injection signal generating means for
10. The isolated operation detection apparatus for a distributed power supply according to claim 9, further comprising: (b) injection current forming means for forming the injection current using the injection signal.

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