JP5079214B2 - Accident direction identification device for distribution lines - Google Patents

Description

  The present invention relates to an accident direction discriminating apparatus for a distribution line, and more particularly, to a distribution line capable of accurately discriminating the direction of a ground fault even when a distributed power source is present in the system or when a substation is switched. The present invention relates to an accident direction discriminating device.

  As an accident direction discriminating device in a conventional overhead distribution line, the one shown in Patent Document 1 has been proposed. The fault direction discriminating apparatus includes a first detection unit that detects a phase voltage and a phase current of a distribution line, a second detection unit that detects a zero-phase voltage and a zero-phase current of the distribution line, and the phase voltage and the phase current. Power transmission direction discriminating means for discriminating the power transmission direction of the distribution line on the basis of the phase difference. In addition, the fault direction discriminating device has a ground fault detecting means for detecting a ground fault based on a voltage value of the zero phase voltage and a current value of the zero phase current, and when the ground fault is detected, A ground fault direction determining means for determining a direction of the ground fault based on a power transmission direction and a phase difference between the zero phase voltage and the zero phase current. Further, the accident direction discriminating apparatus includes display means for performing a predetermined display when the ground fault direction determining means determines that the direction of the ground fault is the load side.

Then, when locating the ground fault on the load side, the current direction is determined from the phase difference between the single phase voltage and phase current, and the ground fault direction is determined from the phase difference between the zero phase voltage and the zero phase current at the time of the ground fault. Make a decision. Whether or not the load-side ground fault has occurred is determined by the AND condition of the tidal current direction and the ground fault direction. In this case, as for the tidal current direction, the calculation result immediately before the occurrence of the ground fault accident is stored in the storage means, and the load side ground fault accident is determined in comparison with the ground fault direction at the time of the ground fault occurrence.
JP-A-2-275373

  However, since the conventional accident direction discriminating apparatus has not been assumed in recent years that a distributed power source is connected to the distribution system and power is supplied from other than the substation, the following problems are newly introduced. occured. That is, since the power transmission direction may be changed depending on the distributed power source, an unnecessary display of displaying an accident on the power source side in addition to a ground fault on the load side is performed. The reason for such erroneous display will be described based on the system configuration of case 1 in FIG. When a ground fault occurs between the first indicator 21 and the second indicator 22 connected to the substation 11A, the determination result of the first indicator 21 is that the power transmission direction is forward tidal current (K → L). Since the load-side ground fault is based on the substation 11A, the ground fault is determined as “present”. On the other hand, when a current is supplied from the distributed power source 15 to the second indicator 22 and the power transmission direction becomes reverse power flow (L → K), the second indicator 22 is caused by a ground fault on the power source side. In spite of the fact, the load side ground fault is “yes”. As described above, the first display 21 performs correct display, but the second display 22 performs incorrect display. In case 2 shown in FIG. 4, both the first display 21 and the second display 22 are in reverse flow, and the first display 21 determines that the load-side ground fault is “none”, and the second display 22 determines that the load-side ground fault is “present”. In this case, both the first display 21 and the second display 22 make a wrong determination. Therefore, there is a problem that accurate display cannot be performed.

In addition, if the above-mentioned ground fault accident is erroneously displayed, the correct accident point cannot be specified, so that it takes time to recover the accident.
The present invention solves the above-mentioned problems in the prior art and accurately determines whether or not the load side ground fault is based on the substation even when there is a reverse power flow from the distributed power source. An object of the present invention is to provide an accident direction discriminating device for a distribution line that can be used.

In order to solve the above problems, the invention described in claim 1 is a first detection means for detecting a phase voltage and a phase current of a distribution line, and a first detection unit for detecting a zero-phase voltage and a zero-phase current of the distribution line. 2 detection means, first transmission direction determination means for determining a transmission direction of the distribution line based on a phase difference between the phase voltage and phase current, a voltage value of the zero phase voltage, and a current value of the zero phase current. A ground fault detection means for detecting a ground fault based on the direction of the power fault and the direction of the ground fault based on the phase difference between the zero phase voltage and the zero phase current when the ground fault is detected. A first ground fault direction determining means, a second power transmission direction determining means for newly determining a power transmission direction at the time of power recovery after the distribution line is re-closed, and the first ground fault direction determining means. And the direction of the ground fault determined by the second power transmission direction discriminating means. A second ground fault direction determining unit newly determines the direction of the ground fault by comparing the new transmission direction, when the second ground direction determination means determines the direction of the ground fault and the load side The gist of the invention is that it includes display means for performing predetermined display.

According to a second aspect of the present invention, in the first aspect, the power transmission direction is switched to the third power transmission direction determining means for determining the power transmission direction of the distribution line based on the phase difference between the phase voltage and the phase current. Phase current phase difference calculating means for calculating the phase difference of the phase current change before and after the current, and the phase difference of the phase voltage change and the phase current change before and after the power transmission direction is switched Phase voltage change / phase current change phase difference calculation means to be calculated, and a phase for determining whether or not the phase difference calculated by the phase current phase difference calculation means is within a preset predetermined phase range. Current phase range determination means and change phase range determination means for determining whether or not the phase difference obtained by the phase voltage change / phase current change phase difference calculation means is within a predetermined phase range set in advance. And the phase current phase range Power transmission direction correction means for correcting the power transmission direction based on determination results by the determination means and the change phase range determination means, and power transmission corrected by the power transmission direction correction means when the ground fault is detected. An uninterruptible ground fault direction determining means for determining a direction of the ground fault accident based on a direction and a phase difference between the zero phase voltage and the zero phase current, and determining the uninterruptible ground fault direction The gist is to perform a predetermined display on the display means when the means determines that the direction of the ground fault is the load side.

The invention according to claim 3 is the amount of change in phase voltage according to claim 2 , wherein the change amount of the phase voltage and the phase current is calculated, and whether the calculation result exceeds a predetermined set range is determined. further provided a phase current change calculation determination means, said third power transmitting direction determination means, whether said third transmission direction is determined by the transmission direction identification means is changed to continue preset time If the set time continues, the process proceeds to the processing operation of the phase current phase difference calculation means. On the other hand, if it does not continue, the phase voltage change / phase current change When the change of the phase voltage and phase current is calculated by the minute calculation determination means, it is determined whether or not those calculation results exceed a predetermined setting range, and it is determined that the determination result exceeds the setting range , said phase voltage variation Based on the calculation results of the phase current change phase difference computation means, the phase difference between the variation of the phase voltage and the phase current by the change of phase range determining means determines whether more than a predetermined set range, the determination If the result exceeds the set range, it is determined that the power flow is a reverse power flow from the distributed power source. If not, the gist is that it has a function for determining a reverse power flow by switching the substation.

According to a fourth aspect of the present invention, in the second or third aspect , the first and second power transmission direction determining means have a phase difference between the phase voltage and the phase current in a range of −70 ° to 110 °. A function of determining the power transmission direction of the distribution line as a forward power flow, and determining the power transmission direction of the distribution line as a reverse power flow when the phase difference between the phase voltage and the phase current is within a range of 110 ° to 290 °. The third power transmission direction determining means determines that the power transmission direction of the distribution line is a forward power flow when the phase difference between the phase voltage and the phase current is within a range of −90 ° to 90 °, and the phase voltage When the phase difference between the phase current and the phase current is in the range of 90 ° to 270 ° , the gist of the invention is that it has a function of discriminating the power transmission direction of the distribution line as a reverse power flow .

  According to the first aspect of the present invention, when a ground fault is detected, the direction of the ground fault is determined by the first ground fault direction determining means, and the second power is restored when the distribution line is re-closed after a power failure. The power transmission direction is newly determined by the power transmission direction determination means. The second ground fault direction determination means compares the direction of the ground fault determined by the first ground fault direction determination means with the new power transmission direction determined by the second power transmission direction determination means, and A new direction is determined. For this reason, even when there is a reverse power flow from the distributed power source, it is possible to accurately determine and display the load-side ground fault based on the substation.

In the invention according to claim 2, the power transmission direction is corrected by the third power transmission direction correction unit based on the determination results by the phase current phase range determination unit and the change phase range determination unit. Then, when a ground fault is detected, the ground fault direction determining means at the time of uninterruptible power is determined based on the power transmission direction corrected by the power transmission direction correcting means and the phase difference between the zero phase voltage and the zero phase current. Determine the direction. For this reason, even when there is a reverse power flow from the distributed power source, it is possible to accurately determine and display the load-side ground fault based on the substation.

Hereinafter, one embodiment of an accident direction discriminating device in a distribution line embodying the present invention will be described with reference to FIGS.
As shown in FIG. 6, the substation 11A and the substation 11B are connected by the distribution line 12, and the circuit breaker 13A is provided in the middle, The transfer circuit breaker 14A is provided in this circuit breaker 13A. Then, the ZCT (zero phase current transformer: not shown) of the substation 11A and the GPT (grounded instrument transformer: not shown) provided in the distribution line 12 are the zero phase of the single-line ground fault that occurs in the distribution line 12. When a voltage and a zero phase current are detected, the ground fault relay operates to trip the circuit breaker 13A and disconnect the distribution line 12 from the substation 11A. The other end of the distribution line 12 is connected to another substation 11B, a circuit breaker 13B, and a protective relay 14B so that the power supplied to the load 20 can be switched as necessary. A distributed power source 15 is disposed in the middle of the distribution line 12 to supply power to the load 20. The distributed power supply 15 is provided with a circuit breaker 13C and a transfer interruption device 14C, and the transfer interruption device 14C operates based on a signal from the transfer interruption device 14A. Then, the distributed power supply 15 is shut off after a predetermined time. A first indicator 21 and a second indicator 22 are mounted in the middle of the distribution line 12 corresponding to a section switch not shown. Since the first display 21 and the second display 22 are configured in the same manner, only one first display 21 will be described with reference to FIG.

  High-voltage sensors 30 are respectively provided in the R phase, S phase, and T phase of the distribution line 12. The high-voltage sensor 30 includes coupling capacitors 31a, 31b, and 31c that detect the phase voltage of each phase, and current transformers 32a, 32b, and 32c. A voltage signal processing circuit 34 for outputting a zero-phase voltage signal V0 based on phase voltage signals Vr, Vs, Vt from a three-phase distribution line is connected to the coupling capacitors 31a, 31b, 31c. The current transformers 32a, 32b, and 32c are connected to a current signal processing circuit 35 for outputting a zero-phase current signal I0 based on phase current signals Ir, Is, and It from three-phase distribution lines. ing.

Next, a configuration for performing ground fault determination display in the “power failure present mode” in which a ground fault occurs and the circuit breaker 13A operates will be described.
The coupling capacitor 31a and the current transformer 32a are connected in parallel with a first power transmission direction determination circuit 36 as a first power transmission direction determination means and a second power transmission direction determination circuit 37 as a second power transmission direction determination means. The first power transmission direction discriminating circuit 36 continuously discriminates and stores the power transmission direction of the R-phase distribution line based on the phase difference between the R-phase voltage Vr and the phase current Ir. The second power transmission direction discriminating circuit 37 newly discriminates and stores the power transmission direction when power is restored after the distribution line 12 is cut off. In this embodiment, as shown in FIG. 7A, both discriminating circuits 36 and 37 have the phase of the phase current Ir within the range of -70 ° to 110 ° with respect to the phase angle 0 ° of the R phase voltage. When there is, it is determined as forward flow (K → L), and when there is not, it is determined as reverse flow (L → K).

  The voltage signal processing circuit 34 and the current signal processing circuit 35 are connected to a ground fault detection circuit 38 as a ground fault detection means, and a ground fault occurs based on the voltage value of the zero phase voltage V0 and the current value of the zero phase current I0. Is supposed to be detected. For example, in the case of a 6 kV distribution line, a ground fault is determined when the zero-phase current level reaches 100 mA and the zero-phase voltage level reaches 380 V. A first ground fault direction determination circuit 39 as a first ground fault direction determination means is connected to the first power transmission direction determination circuit 36 and the ground fault detection circuit 38. When a ground fault is detected, the direction of the ground fault is determined based on the phase difference between the power transmission direction and the zero phase voltage V0 and the zero phase current I0. In this embodiment, as shown in FIG. 8, the phase of the zero-phase current I0 is within the range of -30 ° to 150 ° with respect to the phase angle 0 ° of the zero-phase voltage, and the transmission direction is forward. When it is determined that the tidal current is (K → L), it is determined that there is a ground fault on the load side. Further, when there is no phase of the zero phase current I0 within the phase of −30 ° to 150 ° and it is determined that the reverse power flow (L → K) is detected, it is determined that the load side ground fault has occurred. This determination result is stored by the storage means provided in the first ground fault direction determination circuit 39.

  A second ground fault direction determination circuit 40 as a second ground fault direction determination means is connected to the second power transmission direction determination circuit 37 and the first ground fault direction determination circuit 39. Then, the direction of the ground fault is described later based on the direction of the ground fault determined and stored by the first ground fault direction determination circuit 39 and the new power transmission direction determined by the second power transmission direction determination circuit 37. As a result, a new determination is made. The second ground fault direction determination circuit 40 is connected to an indicator lamp 41 for displaying the ground fault when the newly determined direction of the ground fault is the load side.

  The first and second power transmission direction discriminating circuits 36 and 37, the ground fault detection circuit 38, and the first and second ground fault direction judging circuits 39 and 40 described above are the circuit breakers when a ground fault occurs in the distribution line 12. It functions in the “power failure mode” that operates in a state where 13A trips and the distribution line 12 fails.

  Next, a circuit for performing determination display of a section in which the zero-phase voltage V0 and the zero-phase current I0 are generated in the “no power failure mode” in which the circuit breaker 13A does not operate even when the zero-phase voltage V0 and the zero-phase current I0 are generated. The configuration will be described.

  The coupling capacitor 31a and the current transformer 32a are connected to a third power transmission direction discriminating circuit 42 as third power transmission direction discriminating means for constantly discriminating and storing the power transmission direction. The third power transmission direction discriminating circuit 42 is connected to a substation direction setting switch 43 as substation direction setting means. The substation direction setting switch 43 is used when the first display 21 and the second display 22 are installed in a state where the distribution line 12 has a reverse power flow from the distributed power source 15 and the substation 11A or the substation. It is provided to determine the direction of the place 11B. The switch 43 determines the reference phase of the phase difference between the R-phase voltage Vr and the phase current Ir with reference to the set substation direction. In this embodiment, the substation direction setting switch 43 is set to have a substation on the K side. In this setting condition, as shown in FIG. 7B, when the phase of the phase current Ir is within the range of -90 ° to 90 ° with respect to the phase angle 0 ° of the R-phase voltage, The third power transmission direction discriminating circuit 42 discriminates that the current is a forward power flow (K → L).

  As shown in FIG. 6, the coupling current 31a, the current transformer 32a, and the third power transmission direction discrimination circuit 42 are connected to a phase current phase difference calculation circuit 44 corresponding to a phase current phase difference change means as a phase current phase difference calculation means. Has been. The phase current phase difference calculation circuit 44 calculates the phase difference between the phase currents before and after the power transmission direction is switched to the reverse power flow. The phase current phase difference calculation circuit 44 is connected to a phase current phase range determination circuit 45 as phase current phase range determination means, and the phase difference obtained by the phase current phase difference calculation circuit 44 is set to a predetermined value. It is determined whether or not it is within the phase range (0 ° to 45 °). Further, the phase voltage change amount / phase current change amount for use when the phase difference obtained by the phase current phase difference calculation circuit 44 is outside a predetermined phase range (0 ° to 45 °) set in advance. A phase voltage change / phase current change phase difference calculation circuit 46 is connected as a phase difference calculation means. The phase voltage change / phase current change phase difference calculation circuit 46 calculates the phase difference between the phase voltage change and the phase current change before and after the transmission direction is switched to the reverse power flow. A change phase range determination circuit 47 as a change phase range determination means is connected to the phase voltage change / phase current change phase difference calculation circuit 46, and the phase difference obtained by the phase difference calculation circuit 46 is obtained in advance. It is determined whether or not it is within a set predetermined phase range (−90 ° to 90 °).

  A power transmission direction correction circuit 49 as a power transmission direction correction means is connected to the third power transmission direction determination circuit 42, the phase current phase range determination circuit 45, and the change phase range determination circuit 47, and the phase current phase range determination circuit 45 and the change Based on the determination result of the minute phase range determination circuit 47, the power transmission direction is corrected. The ground fault detection circuit 38 and the power transmission direction correction circuit 49 are connected to an uninterruptible ground fault direction determination circuit 50 as an uninterruptible ground fault direction determination means. Then, when a ground fault is detected, the substation 11A set in advance based on the transmission direction corrected by the transmission direction correction circuit 49 and the phase difference between the zero-phase voltage V0 and the zero-phase current I0 is used as a reference. It is determined whether or not there is a load side ground fault. The uninterruptible ground fault direction determination circuit 50 is connected to the indicator lamp 41.

  In this embodiment, the phase current phase difference calculation circuit 44, the phase current phase range determination circuit 45, the phase voltage change / phase current change phase difference calculation circuit 46, and the change phase range determination circuit 47 A reverse flow type discrimination circuit 48 as a discrimination means is configured.

Next, the function of each circuit 44, 45, 46, 47, 49, 50 will be described.
The phase current phase difference calculation circuit 44 and the phase current phase range determination circuit 45 determine whether the current is a reverse power flow from the distributed power source 15 or a reverse power flow by switching from the substation 11A to the substation 11B. The phase current phase difference calculation circuit 44 calculates the phase difference Δδ for the phase current change before and after the determination signal (the type of reverse power flow is unknown) from the uninterruptible power transmission direction determination circuit 42 is output. When the phase difference Δδ corresponding to the phase current change before and after the change of the power transmission direction is within the predetermined phase range of 0 ° to 45 ° shown in FIG. 9, it is determined that the power flow is reverse from the distributed power source 15. Further, when the phase difference Δδ is outside the predetermined phase range of 0 ° to 45 °, from the determination results by the phase voltage change / phase current change phase difference calculation circuit 46 and the change phase range determination circuit 47, It is determined whether the current is a reverse power flow from the distributed power source 15 or a reverse power flow by switching from the substation 11A to the substation 11B.

  The phase voltage change / phase current change phase difference calculation circuit 46 outputs the phase voltage Vr before and after the determination signal (the type of reverse power flow is unknown) from the uninterruptible power transmission direction determination circuit 42. The phase difference between the change ΔVr and the change ΔIr of the phase current Ir is calculated. If the phase difference ΔVr−ΔIr with respect to the current change ΔIr when the voltage change ΔVr is, for example, 0 ° is in the range of −90 ° to 90 ° shown in FIG. Judged as a tidal current. Further, when the phase difference ΔVr−ΔIr is outside the range of −90 ° to 90 °, it is determined that the reverse power flow is from the distributed power source 15.

  By the way, when a loop point switch (not shown), which is one of the procedures for switching the substations 11A and 11B, is turned on, the voltage phase difference between the left and right of the loop point switch is as close as possible. Operational standards for electric power companies are defined as sometimes done. Further, when the distributed power source 15 is also connected to the distribution system, it is necessary to maintain the voltage of the distribution system at an appropriate value. From these facts, an operation for turning on the voltage phase of the distributed power source 15 in accordance with the voltage phase of the distribution system is performed mainly by using an automatic synchronizing device or the like. Therefore, switching of the substations 11A and 11B or the distributed type Even when the power supply 15 is connected, no significant phase change appears in the voltage. However, since the current is not synchronized like the voltage phase, a change appears in the phase angle of the phase current before and after the transmission direction is changed. At this time, in the reverse power flow from the distributed power source 15, the phase change of the phase current is gentle, and the phase difference Δδ corresponding to the phase current change is small. This is because the power supply capacity of the distributed power supply 15 is naturally smaller than the power supply capacity of the substation 11A (11B), and therefore follows the phase current supplied from the substation 11A (11B) to the connected distribution system. This is because the current from the distributed power supply 15 is supplied to the distribution system so as to gradually increase. Further, in the reverse power flow caused by switching of the substation 11A (11B), the phase change of the phase current is quick and the phase difference Δδ corresponding to the phase current change is large. This is because the power supply capacity of the substation 11A (11B) to be switched has sufficient power supply capacity to supply the distribution system, so that it does not follow the phase current already flowing in the distribution system to be supplied. This is because the current phase changes.

  However, in a distribution system in which the distributed power source 15 is connected, when a large-capacity load comparable to the output of the distributed power source 15 is dropped from the distribution system, the phase change of the phase current is quick. The phase difference Δδ corresponding to the phase current change is increased.

  Therefore, when the phase difference Δδ corresponding to the phase current change becomes large, in order to distinguish between the reverse flow caused by switching of the substations 11A and 11B and the reverse flow caused by the distributed power source 15, before and after the change in the transmission direction. The phase difference between the phase voltage change and the phase current change was added to the judgment conditions to determine the type of reverse power flow.

  The reason why the predetermined phase range, which is a criterion for determining the phase difference Δδ corresponding to the phase current change, is set to the aforementioned 0 ° to 45 ° is as follows. That is, in the actual distribution line, set based on data collected by testing, and when the phase difference Δδ corresponding to the phase current change is within the range of 0 ° to 45 °, the distributed power source 15 This is because it has been found that even if it is determined that the reverse power flow is not a misjudgment, it is difficult to determine the type of the reverse power flow in other cases.

  Next, the phase difference between the phase voltage change and the phase current change before and after the change in the transmission direction used as the next judgment condition when the phase difference Δδ for the phase current change becomes large, and the phase difference The theory for further determining the type of reverse power flow based on the above will be described in turn below.

  The reverse power flow due to the switching of the substations 11A and 11B occurs by the procedure at the time of switching the substations 11A and 11B shown in FIGS. 11A to 11C. FIG. 11A showing the state before the switching is a loop point. The switch (not shown) is opened, the section switch 16A is closed, the section switch 16B is opened, and only the substation 11A is on the power supply side. In FIG. 11 (b) showing the loop state, a loop point switch (not shown) is turned on, both the section switches 16A and 16B are closed, and the substations 11A and 11B are both on the power supply side. Further, FIG. 11 (c) showing after switching, the loop point switch (not shown) is opened, the section switch 16A is opened, the section switch 16B is closed, and the substation 11B is switched to the power supply side. ing. An equivalent circuit of a broken line portion after switching between the substations 11A and 11B shown in FIG. 11C is shown as in FIG.

Here, the phase voltage change ΔV and the phase current change ΔI before and after the change in the power transmission direction are obtained by subtracting the loop state shown in FIG. 11 (b) from the state after the change shown in FIG. 11 (c). And is calculated by the following equations (1) to (3).
<Loop>

＜切り換え後＞

<After switching>

＜切り換え後＞−＜ループ＞

<After switching>-<Loop>

変電所１１Ａ，１１Ｂの切り換えによる相電圧変化分ΔＶと相電流変化分ΔＩの位相差θｓは、第１表示器２１から切り換えられた変電所１１Ｂ側を見たインピーダンス（Ｒ＋ｊＸ）によって決定される。このインピーダンスのうち、抵抗分Ｒは正（Ｒ＞０）であるため、相電圧変化分ΔＶと相電流変化分ΔＩの位相差θｓは、次の不等式（４）のとおりとなり、｜π／２｜以内となる。

The phase difference θs between the phase voltage change ΔV and the phase current change ΔI due to the switching of the substations 11A and 11B is determined by the impedance (R + jX) when the substation 11B side switched from the first display 21 is viewed. Of this impedance, the resistance component R is positive (R> 0), so the phase difference θs between the phase voltage variation ΔV and the phase current variation ΔI is expressed by the following inequality (4): | π / 2 Within |

図１３（ａ）は分散型電源１５からの逆潮流が無い状態を示す。この状態から図１３（ｂ）に示すように分散型電源１５からの逆潮流が有る状態に変化した時の等価回路は、図１４のように示される。

FIG. 13A shows a state where there is no reverse power flow from the distributed power source 15. FIG. 14 shows an equivalent circuit when the state changes from this state to a state where there is a reverse power flow from the distributed power source 15 as shown in FIG.

Here, the phase voltage change ΔV and the phase current change ΔI before and after the change in the power transmission direction are obtained by subtracting the state of no reverse tide from the state of reverse tide from the distributed power supply 15, and (5) to (7).
<No reverse tide>

＜逆潮有＞

<With reverse tide>

＜逆潮有＞−＜逆潮無＞

<With reverse tide>-<No reverse tide>

分散型電源１５からの逆潮流の有無による相電圧変化分ΔＶと相電流変化分ΔＩの位相差θｇは、第１表示器２１から変電所１１Ａ側を見たインピーダンス（Ｒ＋ｊＸ）によって決定される。このインピーダンスのうち、抵抗分Ｒは正（Ｒ＞０）であるため、相電圧変化分ΔＶと相電流変化分ΔＩの位相差θｇは、次の不等式（８）のとおりとなり、｜π／２｜以上となる。

The phase difference θg between the phase voltage change ΔV and the phase current change ΔI due to the presence or absence of reverse power flow from the distributed power supply 15 is determined by the impedance (R + jX) when the first display 21 is viewed from the substation 11A side. Of this impedance, the resistance component R is positive (R> 0), so the phase difference θg between the phase voltage variation ΔV and the phase current variation ΔI is expressed by the following inequality (8), and | π / 2 |

よって、電圧変化分ΔＶｒが０°にある時の電流変化分ΔＩｒとの位相差ΔＶｒ−ΔＩｒが−９０°〜９０°の範囲内の場合には、変電所１１Ａ，１１Ｂの切り換えによる逆潮流と判定でき、前記位相差ΔＶｒ−ΔＩｒが−９０°〜９０°の範囲外の場合には分散型電源１５からの逆潮流と判定できる。

Therefore, when the phase difference ΔVr−ΔIr with respect to the current change ΔIr when the voltage change ΔVr is 0 ° is in the range of −90 ° to 90 °, the reverse power flow caused by switching between the substations 11A and 11B When the phase difference ΔVr−ΔIr is outside the range of −90 ° to 90 °, it can be determined that the power flow is reverse from the distributed power source 15.

  When the phase current phase range determination circuit 45 or the change phase range determination circuit 47 determines that the power flow is reverse from the distributed power source 15, the power transmission direction correction circuit 49 determines and stores the transmission direction determination circuit 42. The power transmission direction before the change is locked and the correct power transmission direction based on the preset substation 11A is maintained. When the change phase range determination circuit 47 determines that the reverse power flow is caused by switching from the substation 11A to the substation 11B, the transmission direction before the change is maintained because the transmission direction is the correct one based on the substation. There is no locking to do. Further, the uninterruptible ground fault direction determination circuit 50 is based on the proper power transmission direction corrected by the power transmission direction correction circuit 49 and the ground fault direction previously determined and stored by the ground fault detection circuit 38. In the hour ground fault direction determination circuit 50, the presence or absence of a load side ground fault is determined.

Next, the operation of the distribution line ground fault direction discriminating apparatus configured as described above will be described separately for the power failure present mode and the power failure absent mode.
(In power failure mode)
In the “power failure mode” that operates in a state where the power distribution line 12 has a power failure, as shown in the timing chart of FIG. 1, the circuit breaker 13A of the substation 11A trips after a predetermined time, and the transfer interruption device 14A operates after a predetermined time. To do. When the transfer interrupting device 14C and the circuit breaker 13C operate, the distributed power supply 15 stops after a predetermined time, and the power of the first display 21 and the second display 22 is turned off. When a predetermined time has elapsed from the ground fault, the circuit breaker 13A of the substation 11A is closed again. Thereafter, the distributed power source 15 is held stopped. In the power failure present mode, it is assumed that the distributed power source 15 is temporarily in an independent operation state after a ground fault, but is stopped after a certain time, is activated after the reclosing of the circuit breaker 13A, and is not in an operating state. This premise is in accordance with “Power System Interconnection Technical Requirements Guidelines” regarding the distributed power source 15.

Next, a known operation until the distributed power source 15 is stopped as shown in FIG. 1 will be described based on the flowchart shown in FIG.
In step S1, the first power transmission direction determination circuit 36 always determines the power transmission direction. In step S2, when the occurrence of the ground fault is detected by the ground fault detection circuit 38, the phase difference between the zero phase voltage V0 and the zero phase current I0 is calculated in step S3. Thereafter, in step S4, it is determined whether or not the normal power transmission direction by the first power transmission direction determination circuit 36 is a forward power flow (K → L). If it is determined Yes in step S4, in step S5, the first ground fault direction determination circuit 39 determines whether the ground fault generation phase direction is on the load side (K → L). In the case of Yes, the load side ground fault “presence” is stored in the storage means in step S6 and the load side ground fault is displayed.

  On the other hand, if it is determined No in step S4, in step S7, the second ground fault direction determination circuit 40 determines whether or not the ground fault occurrence phase direction is the power source side (L → K). In this case, in step S6, the load-side ground fault “present” is stored in the storage means, and the load-side ground fault is displayed. In the case of No, the load-side ground fault “none” is stored by the storage means in step S8, and the load-side ground fault accident is not displayed. On the other hand, if No in step S5, the process proceeds to step S8.

Next, the ground fault direction determination display operation when the circuit breaker of the substation 11A is reclosed will be described based on the flowchart shown in FIG.
In step S <b> 1 of FIG. 3, the second power transmission direction determination circuit 37 determines the power transmission direction at the time of power recovery. In step S2, the ground fault detection circuit 38 checks whether or not a ground fault has occurred. In step S2, in the case of Yes, it is determined in step S3 whether or not the power transmission direction at the time of power recovery is forward flow (K → L). If YES in step S3, it is determined in step S4 whether or not the ground fault generation phase direction previously determined and stored by the first ground fault direction determination circuit 39 is on the load side (K → L). And when it is judged as Yes in step S4, the display of the load side ground fault by the indicator lamp 41 is continued in step S5.

  On the other hand, if it is determined No in step S3, it is determined in step S6 whether or not the ground fault generation phase direction stored by the second ground fault direction determination circuit 40 is the power supply side (L → K). The And in the case of Yes, the display of the load side ground fault accident by the indicator lamp 41 is continued in step S5. In the case of No, the display of the load side ground fault by the indicator lamp 41 is restored in step S7 and switched to non-display.

  4 and 5 show the power transmission direction of the first indicator 21 and the second indicator 22 and the presence or absence of a load-side ground fault by dividing the system configuration at the time of occurrence of a ground fault into cases 1 to 5. It is. Case 1 shows a state in which a ground fault has occurred between the first display 21 and the second display 22 and power is supplied from the distributed power supply 15 to the second display 22. Conventionally, both the first indicator 21 and the second indicator 22 have a problem that the load side ground fault is determined to be “present”, but in the case of the present embodiment, the first indicator 21 is The correct determination is made that the ground fault is “present” and the second display 22 is “not present”.

  Case 2 shows a state in which a ground fault has occurred between the first display 21 and the second display 22 and both the first display 21 and the second display 22 have determined reverse power flow. Conventionally, there is a problem that the first display 21 determines that the load-side ground fault is “absent” and the second display 22 erroneously determines that the load-side ground fault is “present”. . However, in this embodiment, both the first display 21 and the second display 22 perform correct determination display.

Case 3 shown in FIG. 5 indicates a state in which the substation 11A is switched to the substation 11B and the first display 21 and the second display 22 are determined to have reverse power flow. In case 4, the distributed power source 15 does not exist, and both the first display 21 and the second display 22 show a forward power flow state. Further, Case 5 shows a state in which the system is switched to the substation 11B in a system without the distributed power source 15 and both the first indicator 21 and the second indicator 22 are determined to have reverse power flow. Regarding Case 3 to Case 5, it was confirmed that both the first display 21 and the second display 22 performed correct determination display, and that the correct determination display was performed even in the known determination method shown in FIG.
(In case of no power failure mode)
15 and 16 show the determination of the transmission direction when the distributed power source 15 is connected to the distribution system, the substations 11A and 11B are not switched, and the transmission direction changes due to the reverse power flow by the distributed power source 15. It is a timing chart which shows the display operation of the load side ground fault on the basis of the correction operation and the substation 11A of the 1st indicator 21 and the 2nd indicator 22 at the time of a ground fault accident. FIG. 17 is a timing chart showing the same display operation as in FIGS. 15 and 16 when the distributed power source 15 is not connected or disconnected and the substation 11A is switched to the substation 11B. is there.

Next, the power transmission direction correction operation will be described with reference to the flowchart of FIG. 18 related to FIGS. 15 and 16.
In step S1 of FIG. 18, the substation direction is set to the K side (substation 11A) by the substation direction setting switch 43. In step 2, the third power transmission direction discrimination circuit 42 always determines the power transmission direction. In step S3, it is similarly determined by the power transmission direction determination circuit 42 whether or not the power transmission direction has been continuously changed for one second. In the case of Yes, the phase current phase difference calculation circuit 44 before and after the power transmission direction change is determined in step S4. The phase difference Δδ for the phase current change is calculated. In step S5, the phase current phase range determination circuit 45 determines whether or not the phase difference Δδ for the phase current change before and after the change is greater than 45 °.

  In step S5, it is determined whether or not there is a reverse power flow from the distributed power source 15. If No, that is, a reverse power flow from the distributed power source 15, the power transmission direction correction circuit 49 changes the power transmission direction in step S8. The power transmission direction is corrected by locking the power transmission direction before the change, and the power transmission direction is stored (set) in the storage medium of the power transmission direction correction circuit 49 as forward power flow (K → L).

  On the other hand, if it is determined Yes in step S5 described above, the voltage difference (ΔV) and the current change (before and after the change in the transmission direction are detected by the phase voltage change / phase current change phase difference calculation circuit 46 in step S6. The calculation of the phase difference ∠ (ΔV−ΔI) of ΔI) is performed. In step S7, whether or not the absolute value of the phase difference between the voltage change (ΔV) and the current change (ΔI) before and after the change | Δ (ΔV−ΔI) | Is determined by That is, in step S7, it is finally determined whether the reverse power flow is due to switching of the substation or the reverse power flow from the distributed power source 15. If yes, that is, if the reverse power flow is from the distributed power source 15, in step S8, As described above, the power transmission direction after the power transmission direction change is corrected by the power transmission direction correction circuit 49 being locked as the power transmission direction before the change is corrected, and the power transmission direction is changed to the forward current (K → L) is stored (set). In step S10, the third power transmission direction determination circuit 42 always determines the power transmission direction. In step S11, it is similarly determined by the uninterruptible power transmission direction discriminating circuit 42 whether or not the power transmission direction has continued for 1 second and returned to the power transmission direction before the change. If yes, in step S13, the power transmission direction correction circuit The lock for maintaining the transmission direction before the change stored (set) in the storage medium 49 and the storage (set) of the forward flow (K → L) are released, and in step S2, the third transmission direction is again performed. The determination circuit 42 always determines the power transmission direction.

  On the other hand, when it is determined No in step S11, in step S12, the phase difference Δδ of the phase current change ΔI before and after the change is larger than 30 °, and the magnitude (current value) of the phase current change ΔI before and after the change. ) Is larger than 5A (ampere) by the phase current phase range determination circuit 45, and in the case of Yes, before the change stored (set) in the storage medium (not shown) of the power transmission direction correction circuit 49 The release of the lock for maintaining the power transmission direction and the storage (set) of the forward flow (K → L) are released, and the process returns to step S6. On the other hand, when it determines with No in step S12, it returns to step S10.

  On the other hand, when it is determined No in step S7 described above, that is, when it is determined that the reverse power flow is caused by switching between the substations 11A and 11B, in step S9, the power transmission direction correction circuit 49 transmits the power after the power transmission direction is changed. The power transmission direction is stored (set) as a reverse power flow (L → K) in the storage medium of the power transmission direction correction circuit 49 without being locked in the power transmission direction before the change, and then in step S2, the third power transmission direction is stored. The determination circuit 42 always determines the power transmission direction.

  According to the flowchart shown in FIG. 18, as a conclusion, in the case of reverse power flow due to switching of the substations 11A and 11B, the correction is not made to lock the power flow direction after the power flow change, and the case of reverse power flow by the distributed power source 15 In this case, the tidal current direction is locked to the power transmission direction before the change, so that correction is performed.

  FIG. 19 shows the case where the substation direction is set to the L side by the substation direction setting switch 43 in step S1, and is the same as the operation of FIG. The outline of the different points is as follows. In step S7, whether or not the absolute value of the phase difference between the voltage change (ΔV) and the current change (ΔI) before and after the change in the transmission direction | Δ (ΔV−ΔI) | In the case of Yes, that is, a reverse power flow from the distributed power source 15, in step S8, the power transmission direction after the power transmission direction change is changed by the power transmission direction correction circuit 49 in step S8. It is corrected by being locked as it is, and the power transmission direction is stored (set) in the storage medium of the power transmission direction correction circuit 49 as the forward power flow (L → K). On the other hand, when it is determined No in step S7, in step S9, the storage medium of the power transmission direction correction circuit 49 is not locked by the power transmission direction correction circuit 49 without changing the power transmission direction after the power transmission direction change. The power transmission direction is stored (set) as reverse power flow (K → L).

Next, the load-side ground fault display operation performed in conjunction with the power transmission direction reverse correction operation described above will be described with reference to the flowchart of FIG.
In step S1 of FIG. 15, it is detected whether or not a ground fault has occurred by the ground fault detection circuit 38. In step S2, the ground fault detection circuit 38 similarly calculates the zero phase voltage and the zero phase current. Next, the power transmission direction stored (set) in the storage medium (not shown) of the power transmission direction correction circuit 49 in the process performed based on the flowchart of FIG. 18 or FIG. It is determined by the circuit 50 whether the current is forward (K → L). In the case of Yes, the result of the calculation in step S2, that is, if the phase difference between the zero-phase voltage and the zero-phase current is within the phase range of -30 ° to 150 °, the uninterruptible ground fault direction determination circuit in step S4 50, it is determined as a load-side ground fault (K → L), and when the phase difference between the zero-phase voltage and the zero-phase current is outside the above phase range, it is determined as a power-supply side ground fault (L → K). If it is determined Yes in step S4, the load side ground fault is displayed by the indicator lamp 41 in step S5.

  On the other hand, if it is determined No in step S3, it is determined in step S6 by the uninterruptible ground fault direction determination circuit 50 whether or not the ground fault occurrence phase direction is the load side ground fault (L → K). In this case, a load-side ground fault is displayed in step S1. If it is determined No in step 5, the process proceeds to step S7, and the load-side ground fault is not displayed. Furthermore, when it is determined No in step S4, the process proceeds to step S7.

Here, the reason why the phase range for determining the power flow direction of the third power transmission direction determination circuit 42 is set to a range of −90 ° to 90 ° will be described below.
The active power changes when the reverse power flow from the distributed power source 15 reaches and when the substations 11A and 11B are switched. The effective power P is represented by the following equation, assuming that the phase voltage V, the phase current I, the phase voltage V, and the power factor angle θ of the phase current I are:

P = 3V ・ Icosθ
In the above equation, cos θ becomes 0 at 90 ° or −90 °, and becomes θ → 90 ° → θ> −90 ° or θ> −90 ° → θ <90 °, and the value changes from positive to negative, and the polarity changes. From this, it can be seen that the tidal direction changes clearly in the determination process, so the range of −90 ° to 90 ° was set. In addition, when the phase range of −90 ° to 90 ° is stored in the storage medium of the uninterruptible power transmission direction discriminating circuit 42, the forward flow (K → L) is stored (set), and the reverse flow (otherwise) L → K) is stored (set).

Next, the operation of determining the load-side ground fault based on the substation by the uninterruptible ground fault direction determination circuit 50 will be further described.
The phase current phase difference calculation circuit 44 and the phase current phase range determination circuit 45, and the phase voltage change / phase current change phase difference calculation circuit 46 and the change phase range determination circuit 47 respectively perform calculations. Then, in the uninterruptible ground fault direction determination circuit 50, when switching from the substation 11A to the substation 11B, the substation 11B direction in which the transmission direction stored (set) in the power transmission direction correction circuit 49 has changed and the ground fault direction It is determined whether or not the load side ground fault is based on the substation 11B with an AND condition. Conversely, in the case of reverse power flow from the distributed power source 15, the power transmission direction locked as the substation 11A direction before the power transmission direction stored (set) in the power transmission direction correction circuit 49 is changed, and the ground fault direction It is determined whether or not the load side ground fault is based on the substation 11A with the AND condition.

  As an example, the polarity of the active power changes due to the interconnection of the distributed power supply 15 is installed between the distributed power supply 15 and the load 20 that is covered only by the reverse power flow of the distributed power supply 15. This is because the second display 22 is in a range indicating reverse power flow (L → K). On the other hand, the first indicator 21 is in a position where the power flow of the distributed power source 15 does not reach and is covered by the supply from the substation, so that even when the distributed power source 15 is connected, the forward power flow ( K → L), the polarity does not change, and it is possible to determine whether or not the reverse power flow from the distributed power source 15 has reached. As a subsequent process, the power transmission direction of the second display 22 is corrected, and the AND condition between the power transmission direction and the ground fault direction that locks the substation direction before the power transmission direction stored (set) in the power transmission direction correction circuit 49 changes. To determine the load-side ground fault based on the substation. The power transmission direction of the first indicator 21 is based on the substation with the AND condition of the power transmission direction and the ground fault direction that does not lock the substation direction stored (set) in the power transmission direction correction circuit 49 without changing the substation direction. Determine the load side ground fault.

According to the accident direction discriminating device in the distribution line of the above embodiment, the following features can be obtained.
(1) In the above embodiment, in the power failure present mode, the ground fault direction is determined by the first ground fault direction determination circuit 39 based on the determination result of the first power transmission direction determination circuit 36, and the determination result is stored. After the circuit breaker 13A is reclosed, the ground fault direction is determined by the second ground fault direction determination circuit 40 based on the determination result of the second power transmission direction determination circuit 37, and is displayed in the case of a load side ground fault. . For this reason, even if it is the system | strain with which the distributed power supply 15 is connected, a load side ground fault can be determined correctly and can be displayed.

  (2) In the above embodiment, when the distributed power source 15 is interconnected and the power transmission direction changes based on the determination result of the third power transmission direction determination circuit 42 in the power failure-free mode, the phase current phase difference calculation circuit 44 calculates the phase difference Δδ corresponding to the phase current change, and the phase current phase range determination circuit 45 determines whether or not the phase difference before and after the change is in the range of 0 ° to 45 °. Is in the range of 0 ° to 45 °, it is determined that the power flow is reverse from the distributed power source 15. On the other hand, if the phase difference before and after the change is 0 ° to 45 °, the phase voltage change / phase current The change phase difference calculation circuit 46 calculates the phase difference between the voltage change ΔV and the current change ΔI. Then, the change phase range determination circuit 47 determines whether or not the phase difference before and after the change is within a range of −90 ° to 90 °.

  Further, whether or not the power transmission direction after the change of the power transmission direction is a forward power flow (K → L) is stored (set) in the power transmission direction correction circuit 49. Based on the stored (set) correction result of the power transmission direction, the ungrounded ground fault direction determination circuit 50 determines the load-side ground fault. Therefore, it is possible to accurately determine whether or not a load-side ground fault occurs even if the power transmission direction changes during an uninterruptible power failure.

  Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 21 is a block circuit diagram showing another example of the power transmission direction discriminating device, and FIGS. 22 and 23 are flowcharts of processing operations based on the circuit diagram of FIG. In this other embodiment, as shown in FIG. 21, the phase voltage as the phase voltage change / phase current change calculation determination means is provided upstream of the phase voltage change / phase current change phase difference calculation circuit 46. A change / phase current change calculation determination circuit 51 is connected. The calculation determination circuit 51 has a function of determining whether or not the phase voltage change ΔV and the current change ΔI exceed a set value and calculating a phase difference between the phase voltage change ΔV and the current change ΔI. Yes.

  And when it is judged No in step S3 shown in FIG. 18 of embodiment mentioned above, the process of steps S15-S17 shown in FIG. 22 is performed. In step S15, the arithmetic determination circuit 51 determines whether or not the voltage change ΔV of the phase voltage and phase current exceeds a set value (eg, 3V) and whether the current change ΔI exceeds a set value (eg, 3A). In this case, in step S16, the phase difference calculation circuit 46 calculates the phase difference ∠ΔV−ΔI between the voltage change ΔV and the current change ΔI before and after the change of the phase voltage and phase current. Next, in step S17, it is determined whether or not the calculated phase difference ∠ΔV−ΔI is greater than or equal to a predetermined phase angle (90 °), and whether or not the determination result has exceeded a preset number of times. Be counted. And when it is judged as Yes in step S17, it determines with the reverse power flow from the distributed power supply 15, and transfers to step S8. On the other hand, if it is determined No in step S17, it is determined that the reverse flow is caused by switching of the substation, and the process proceeds to step S9.

The reason why Steps S15 to S17 are provided will be described below.
In step S3, when the power transmission direction continuously changes for 1 second, it can be determined that the power transmission direction has changed in most cases. However, in the rare case, a reverse power flow caused by switching between the substations 11A and 11B and a reverse power flow from the distributed power source 15 can be considered even in the case where the set time is 1 second or less. That is, in the case of switching from the substation 11A to the substation 11B, for example, the power flow from the substation 11B may or may not reach the first display 21 depending on the magnitude of the output of the distributed power source 15. When the output level of the power supply 15 fluctuates within 1 second, the power transmission direction may be switched in a short time (1 second or less). In the case of reverse power flow from the distributed power source 15, for example, when the first indicator 21 is installed between the interconnection point of the distributed power source 15 and the load 20, the output fluctuation of the distributed power source 15. Or the power transmission direction may be switched in a short time (1 second or less) due to a change in power consumption of the load 20. Therefore, even when the predetermined set time is 1 second or less, the discrimination accuracy can be improved by discriminating whether the reverse power flow is caused by switching between the substations 11A and 11B or the reverse power flow from the distributed power source 15.

Next, the reason why it is determined in step S17 whether or not the number of times that the phase difference is 90 ° or more has exceeded the set number will be described.
If NO in step S3, the voltage difference ΔV is 3V and the current change ΔI exceeds 3A in step S15. The voltage and current other than the phase are used as discriminating elements. Whether or not the phase difference ΔV−ΔI is 90 ° or more is calculated from the phase voltage and phase current in a non-constant state using the change phase range determination circuit 47. Therefore, it was decided to check whether there was a change more than the set number of times. The reason for the confirmation is that in step S3, the power transmission direction does not continue for 1 second, and the phase difference ∠ΔV−ΔI is determined from the phase voltage and phase current in a state where the phase has changed in a short time. In a predetermined determination time for determination (for example, 40 ms before and after the change in this embodiment), the set number of times is set in order to improve the determination accuracy, and a condition of a large number of times is set. In Step 3, in the case of Yes, since the power transmission direction continues for 1 second, the phase difference ∠ΔV−ΔI does not change in Step S7, but the same processing as in Step S17 described above may be performed. .

  FIG. 23 is a flowchart when the substation direction is set to the L side. This processing operation is the reverse of whether the substation direction in FIG. 19 is within the predetermined setting range in the determinations of steps S7 and S17 in the processing operations when the substation direction is set to the K side. Further, in steps S8 and S9, the criteria for not locking the substation direction is reversed, but the other processing operations are the same as the processing operations in FIG.

Next, still another embodiment of the present invention will be described with reference to FIGS.
FIG. 24 is a block circuit diagram showing another example of the power transmission direction discriminating device, and FIGS. 25 and 26 are flowcharts of processing operations based on the circuit diagram of FIG. In the block circuit of FIG. 24, the third power transmission direction determination circuit 42, the phase difference calculation circuit 44, and the phase current phase range determination circuit 45 are omitted, and the calculation determination circuit 51 is connected in front of the calculation circuit 46. . The calculation determination circuit 51 is connected to the substation direction setting switch 43.

  In this embodiment, as shown in FIG. 25, the substation direction is set to the K side, and then the process proceeds to steps S2, S3, and S4 similar to steps S15, S16, and S17 described in FIG. Furthermore, the process proceeds to steps S5 to S11 similar to steps S8 to S14 in FIG.

In FIG. 25, the above-described steps S2 to S7 shown in FIG. 22 are omitted. Also, the processing operation of FIG. 25 is the same as the processing operation of FIG.
FIG. 26 is a flowchart when the substation is set to the L side in step S1 of FIG. 25. This processing operation is step S4 of the processing operations when the substation direction of FIG. 25 is set to the K side. In the determination, whether or not it is within a predetermined setting range is reversed. Also, in steps S5 and S6, the criteria for not locking the substation direction is reversed, but the other processing operations are the same as the processing operations in FIG.

  In this other example, the circuit configuration can be simplified because it can be used in a distribution system in which the power transmission direction does not change continuously for one second due to the magnitude of the output of the distributed power supply 15 and the fluctuation of the load 20 on the distribution line. Therefore, the configuration of the accident direction discriminating device can be simplified.

In addition, the said embodiment can be changed and embodied as follows.
The predetermined phase range of the phase current phase range determination circuit 45 may be set to 0 ° to 40 ° or 0 ° to 50 ° instead of 0 ° to 45 °.

The predetermined phase range of the first power transmission direction determination circuit 36 may be set to −90 ° to 90 °.
The first power transmission direction determination circuit 36 may be replaced with the third power transmission direction determination circuit 42.

  The various phase ranges and setting values of the first display 21 and the second display 22 described above may be switched by a switching signal from a substation.

The timing chart which shows operation | movement of each apparatus of a power distribution system when a ground fault occurs. The flowchart which shows the operation | movement which determines the power transmission direction and ground fault generation | occurrence | production phase direction when a ground fault accident generate | occur | produces, and displays a load side ground fault accident. The flowchart which shows the determination operation | movement of a load side ground fault accident. Explanatory drawing which shows the system configuration | structure at the time of a ground fault accident, and the determination result of a 1st indicator and a 2nd indicator. Explanatory drawing which shows the system configuration | structure at the time of a ground fault accident, and the determination result of a 1st indicator and a 2nd indicator. The block circuit diagram which shows the accident direction discrimination apparatus provided with the power transmission direction discrimination function in a distribution line. (A), (b) is explanatory drawing which shows the range of the determination phase angle of the power transmission direction with respect to R phase voltage reference | standard. Explanatory drawing which shows the range of the determination phase angle of the zero phase current with respect to the zero phase voltage reference | standard for determining the direction of a ground fault accident. Explanatory drawing which shows the range of the determination phase angle of phase difference (DELTA) delta for the phase current change which determines whether it is reverse power transmission by switching of a substation, or reverse power flow of a distributed power supply. Explanatory drawing which shows the range of the determination phase angle of the phase difference of phase voltage change part (DELTA) V and phase current change part (DELTA) I which determines whether it is a reverse power flow by switching of a substation, or a reverse power flow from a distributed power supply. (A), (b), (c) is explanatory drawing which shows the procedure when a substation switches. The equivalent circuit diagram after the substation is switched. (A), (b) is explanatory drawing which shows the change state of the power transmission direction by the reverse power flow from a distributed power supply. The equivalent circuit diagram of the state with the reverse power flow from a distributed power supply. The timing chart which shows the ground fault accident display operation | movement when a distributed power supply is connected to a grid | system. The timing chart which shows the ground fault accident display operation | movement when a distributed power supply is connected to a grid | system. The timing chart which shows a ground fault accident display operation when a substation is switched. The flowchart explaining the correction | amendment operation | movement of the power transmission direction at the time of setting a substation direction to the K side. The flowchart explaining the correction | amendment operation | movement of the power transmission direction at the time of setting a substation direction to the L side. The flowchart explaining the determination display operation | movement of a load side ground fault accident. The block circuit diagram which shows another example of the accident direction determination apparatus of this invention. The flowchart explaining the correction | amendment operation | movement of the power transmission direction at the time of setting the substation direction of the accident direction determination apparatus of FIG. 21 to the K side. The flowchart explaining the correction | amendment operation | movement of the power transmission direction at the time of setting the substation direction of the accident direction discrimination device of FIG. 21 to the L side. The block circuit diagram which shows another example of the accident direction discrimination device of this invention. The flowchart explaining the correction | amendment operation | movement of the power transmission direction at the time of setting the substation direction of the accident direction determination apparatus of FIG. 24 to the K side. The flowchart explaining the correction | amendment operation | movement of the power transmission direction at the time of setting the substation direction of the accident direction discrimination device of FIG. 24 to the L side.

Explanation of symbols

  I, Ir: phase current, V, Vr: phase voltage, Δδ, θg, θs, ΔVr-ΔIr, ΔVr-ΔIr ... phase difference, ΔI: phase current change, ΔI, ΔIr ... current change, ΔV, ΔVr ... Voltage change, ΔV: Phase voltage change, I0: Zero phase current, V0: Zero phase voltage, ΔIr, ΔVr: Change, 11A, 11B ... Substation, 12 ... Distribution line, 15 ... Distributed power source, 20 ... load.

Claims (4)

First detection means for detecting a phase voltage and a phase current of the distribution line;
Second detection means for detecting a zero-phase voltage and a zero-phase current of the distribution line;
First power transmission direction determining means for determining a power transmission direction of the distribution line based on a phase difference between the phase voltage and phase current;
A ground fault detection means for detecting a ground fault based on the voltage value of the zero phase voltage and the current value of the zero phase current;
When the ground fault is detected, a first ground fault direction determining unit that determines the direction of the ground fault based on the power transmission direction and a phase difference between the zero phase voltage and the zero phase current;
A second power transmission direction discriminating means for newly discriminating the power transmission direction at the time of power restoration after the distribution line has been shut down and reclosed;
The direction of the ground fault accident determined by the first ground fault direction determining means and the new power transmission direction determined by the second power transmission direction determining means are compared to newly determine the direction of the ground fault accident. 2 ground fault direction determination means;
When the second ground direction determination means determines the direction of the ground fault and the load side, accidents direction determination apparatus in distribution lines and display means for performing predetermined display. In Claim 1, the 3rd power transmission direction discriminating means which discriminates the power transmission direction of the distribution line based on the phase difference of the phase voltage and phase current,
Phase current phase difference calculating means for calculating the phase difference of the phase current change before and after the power transmission direction is switched,
Phase voltage change amount / phase current change phase difference calculation means for calculating a phase difference between the phase voltage change amount and the phase current change amount before and after the power transmission direction is switched,
Phase current phase range determination means for determining whether or not the phase difference calculated by the phase current phase difference calculation means is within a preset predetermined phase range;
A change phase range determination means for determining whether or not the phase difference obtained by the phase voltage change / phase current change phase difference calculation means is within a preset predetermined phase range;
Based on the determination results by the phase current phase range determination unit and the change phase range determination unit, a power transmission direction correction unit that corrects the power transmission direction;
An uninterruptible power failure that determines the direction of the ground fault based on the power transmission direction corrected by the power transmission direction correcting means and the phase difference between the zero phase voltage and the zero phase current when the ground fault is detected. A ground fault direction determination means,
An accident direction discriminating apparatus for a distribution line, wherein when the uninterruptible ground fault direction determining means determines that the direction of the ground fault is the load side, a predetermined display is performed on the display means. 3. The phase voltage change / phase current change calculation determining means for calculating a change in the phase voltage and phase current and determining whether or not the calculation result exceeds a predetermined setting range according to claim 2 . provided, said third power transmitting direction determination means comprises a continuous time determining function determines whether the determined transmission direction changes continue to preset time by the third power transmitting direction discrimination means, When the set time has continued, the process proceeds to the processing operation of the phase current phase difference calculation means. On the other hand, when it has not continued, the phase voltage change / phase current change calculation determination means determines the phase voltage. thereby calculating the variation of the phase currents, their operation results to determine whether more than a predetermined setting range, if the result of the determination exceeds the set range, the phase voltage variation, Phase difference calculation for phase current change Based on the stage of the operation result, the phase difference change in the variation phase range determined phase voltages by means and the phase current is determined whether more than a predetermined set range, the determination result exceeds the set range A fault direction discriminating device in a distribution line, comprising a function of determining a reverse power flow from a distributed power source and determining a reverse power flow by switching of a substation if not exceeded. 4. The power transmission direction of the distribution line according to claim 2 , wherein when the phase difference between the phase voltage and the phase current is in a range of −70 ° to 110 °, the first and second power transmission direction determination means. If the phase difference between the phase voltage and the phase current is within a range of 110 ° to 290 °, the power distribution direction of the distribution line is determined to be a reverse power flow .
When the phase difference between the phase voltage and the phase current is within a range of −90 ° to 90 °, the third power transmission direction determining unit determines that the power transmission direction of the distribution line is a forward power flow, and the phase voltage and the phase A fault direction discriminating device in a distribution line having a function of discriminating a power transmission direction of a distribution line as a reverse power flow when a phase difference of current is within a range of 90 ° to 270 ° .

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