JP2014165954A - Power supply system, power supply control program, and power supply control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve continuity and stability of power supply to an electric power load in a power supply system which uses both power storage means and power generation means when a power failure occurs in a system power source.SOLUTION: A power supply system comprises: power storage means (power storage system 4) for supplying power stored by a system power source (10) to an electric power load (12) when a power failure occurs in the system power source, or for supplying power to the electric power load during self-sustaining operation when no power failure occurs in the system power source; power generation means (power storage system 4) in which power is generated by power supply of the power storage means during the power failure or the self-sustaining operation; detection means (voltage sensor 14) for detecting the power failure or the self-sustaining operation; and control means (control part 26) which has a first protection condition applied to the power generation means during cooperation of the system power source and a second protection condition different from the first protection condition, switches from the first protection condition to the second protection condition upon receiving detection of the detection means, and applies the second protection condition to operate the power generation means.

Description

The present invention relates to a power supply system, a power supply control program, and a power supply control method in which a storage battery and a stationary power generation device such as a fuel cell cogeneration system (hereinafter simply referred to as “FC system”) are combined.

  The FC system generates power according to the amount of power load measured by the current sensor and supplies the power to the power load. In general, the FC system includes a current type inverter and generates power using a system voltage. When a power failure occurs in the grid power, the FC system loses the voltage source and stops generating power.

  Therefore, when the storage battery system is combined with the FC system and the system power supply fails, if the power is supplied from the storage battery system to the FC system, the FC system can continue power generation. Thereby, at the time of a power failure of a system power supply, it is possible to feed the generated power of the FC system to the power load.

It is known that power is supplied to a load by a combination of a photovoltaic power generation device and a storage battery at the time of a power failure of the system power supply (for example, Patent Document 1).

JP 2012-44733 A

  By the way, in a power feeding system including a storage battery system and an FC system, the power consumption of the power load is covered by each power of the system, the storage battery system, and the FC system during grid connection. In this case, if the total impedance from the storage battery system to the power load is Z1, and the total impedance from the FC system to the power load is Z2, Z2 is smaller than Z1, and Z1> Z2 is established.

  At the time of a power failure of the system power supply, if the system power supply is disconnected and the FC system is generated by obtaining power from the storage battery system, both the generated power of the FC system and the power of the storage battery system can be supplied to the power load. .

  The electric power load to which such electric power is supplied includes a special load (special electric power load) that instantaneously consumes a large current during rapid cooling, such as an electric refrigerator. When a large current flows through such a special power load, there is a problem that the power quality from the FC system is instantaneously lowered. That is, when the special power load instantaneously consumes a large current in a state where Z1> Z2 is satisfied, a large current is supplied to the special power load from the FC system having a low impedance.

  When a large current is consumed from the FC system side, the output voltage of the FC system is lowered, the power quality is lowered, and the protection function is activated. In other words, when the output voltage of the FC system is disturbed, the FC system detects the isolated operation, stops the power generation for a certain period of time, or stops the error depending on the number of detected independent operations or the continuous operation detection. Wake up. If the instantaneous large current is not consumed, the generated power of the FC system can be supplied to the power load. On the other hand, because of the instantaneous large current supply, the generated power of the FC system cannot be used during a power failure of the system power supply. There is a problem.

  However, protection functions such as an independent operation detection function of a distributed power source of an FC system or a storage battery system linked to a grid power source are indispensable for grid connection. Satisfaction of the grid interconnection regulations is essential, and no change or invalidation of operating conditions for the protection function of the distributed power supply is allowed in the grid interconnection state.

  When the power generated by the FC system is used in combination with the power supply during a power failure or when the system power is not powered, if the power generation of the FC system stops, the power generated by the FC system cannot be used and the burden on the storage battery increases. However, there is a problem that the consumption of the storage battery becomes significant.

  Such a problem occurs not only in the FC system but also in the case where a power generation means such as solar power generation is used in combination with the power storage means.

Accordingly, an object of the present invention is to increase the continuity and stability of power supply to an electric power load in a power supply system that uses both power storage means and power generation means at the time of a power failure of the system power supply or during a self-sustaining operation with no power failure of the system power supply. is there.

  In order to achieve the above object, the power supply system of the present invention supplies power stored by a system power supply to a power load at the time of a power failure of the system power supply, or supplies power to the power load at the time of a self-sustained operation at a non-power failure of the system power supply. Power storage means for performing power generation during power outage or in the independent operation, power generation means for generating power by feeding the power storage means, detection means for detecting the power outage or the independent operation, and the power generation means during interconnection of the system power supply A first protection condition applied to the first protection condition and a second protection condition different from the first protection condition. Upon detection by the detection means, the first protection condition is switched to the second protection condition. And control means for operating the power generation means by applying the second protection condition.

  In the above power feeding system, the first protection condition and the second protection condition are detection conditions for the independent operation of the power generation means, and the second protection condition is relaxed from the first protection condition, Alternatively, the first protection condition may be invalidated.

  The power supply system includes a storage unit that stores the first protection condition and the second protection condition, and the control unit applies the first protection condition during grid connection and detects the detection unit. The second protection condition may be read from the storage means and changed from the first protection condition to the second protection condition.

  In the power feeding system, the power supply system includes an opening / closing unit between the system power source and the power storage unit, and when the system power source is shut off from the power storage unit by the switching unit, the control unit detects the detection unit or the The power generation means may be operated by switching from the first protection condition to the second protection condition by blocking the opening / closing means or by notification of both, and applying the second protection condition.

  In order to achieve the above object, the power supply control program according to the present invention includes a power storage unit that supplies power to a power load at the time of a power failure of the system power supply, or power supply to a power load at the time of a self-sustained operation at the time of non-power failure of the system power supply, Or a power supply control program for causing a computer mounted on a power supply system including a power generation means for generating power by power supply of the power storage means and supplying the generated power to the power load during the independent operation, In connection with the first protection condition applied to the power generation means, a second protection condition different from the first protection condition is stored in the storage means, and by detecting the power failure or the independent operation, Switching from the first protection condition to the second protection condition, causing the computer to execute a process of operating the power generation means by applying the second protection condition

In order to achieve the above object, the power supply control method of the present invention includes a power storage means for supplying power to a power load at the time of a power failure of the system power supply, or power supply to a power load at the time of a self-sustained operation at the time of non-power failure of the system power supply, Or a power supply control method including power generation means for generating power by power supply of the power storage means and supplying the generated power to the power load at the time of the self-sustained operation, detecting the power failure or the self-sustained operation, At the time of interconnection, together with a first protection condition applied to the power generation means, a second protection condition different from the first protection condition is set, and the first power failure detection or the self-sustaining operation detects the first protection condition. The protection condition is switched to the second protection condition, and the power generation means is operated by applying the second protection condition.

  According to the present invention, the following effects can be obtained.

  (1) Since the power generation means operated by applying the first protection condition during grid connection is operated by applying the second protection condition switched from the first protection condition at the time of power failure of the system power supply The power generation means separated from the system power supply can be operated under relaxed protection conditions. As a result, the continuity and stability of the power supply from the power supply system including the power generation means to the power load are improved.

  (2) During a power failure of the system power supply, even if the load such as an increase in current supplied from the power generation means to the power load increases due to the operating state of the power load, it is possible to avoid power generation stoppage of the power generation means, and The continuity and stability of the power supply are improved.

Other objects, features, and advantages of the present invention will become clearer with reference to the accompanying drawings and each embodiment.

It is a figure which shows the electric power feeding system which concerns on 1st Embodiment. It is a figure which shows the operation | movement at the time of the grid connection (power recovery from a power failure) of a feed system, and a power failure. It is a figure which shows the control function of FC system. It is a figure which shows an example of the hardware of a control part. It is a figure which shows an example of a grid connection protection function data table. It is a figure which shows an example of an independent driving | operation detection (passive system) condition data table. It is a figure which shows an example of an independent driving | operation detection (active system) condition data table. It is a flowchart which shows the process sequence of electric power feeding control. It is a flowchart which shows the process sequence of electric power feeding control. It is a figure which shows the electric power feeding system which concerns on 2nd Embodiment. It is a figure which shows the control function of an electrical storage system and FC system. It is a flowchart which shows the process sequence of electric power feeding control. It is a flowchart which shows the process sequence of electric power feeding control. It is a figure which shows the electric power feeding system which concerns on other embodiment. It is a figure which shows the electric power feeding system which concerns on other embodiment. It is a figure which shows the electric power feeding system which concerns on other embodiment.

[First Embodiment]

<System configuration>

  FIG. 1 shows a power supply system according to the first embodiment. The configuration shown in FIG. 1 is an example, and the present invention is not limited to such a configuration.

  This power supply system 2 is an example of the power supply system of the present invention. The power supply system 2 includes a power storage system 4 and an FC system (fuel cell cogeneration system) 6. The power storage system 4 is an example of power storage means. The FC system 6 is an example of power generation means. The power feeding system 2 is connected to the power distribution system 8. A system power supply 10 is connected to the power distribution system 8 and a power load 12 is connected to the power distribution system 8. At the time of grid connection, power is supplied from the system power supply 10 to the power load 12 through the power distribution system 8, and simultaneously, power is supplied from the power storage system 4 and the FC system 6 to the power load 12 through the power distribution system 8.

  The power storage system 4 receives and stores power from the system power supply 10 at the time of grid connection, and supplies power to the power load 12 and the FC system 4 at the time of a power failure of the system power supply 10. The power storage system 4 includes a voltage sensor 14, a switch 16, an inverter (INV) 18, and a storage battery 20.

  The voltage sensor 14 is a power failure detection unit of the system power supply 10 and is an example of a power recovery detection unit. This voltage sensor 14 is connected to the input end of the power distribution system 8 and detects the occurrence of a power failure and the recovery from the power failure at this input end.

  The switch 16 is inserted on the input end side of the power distribution system 8 and is an example of a shut-off means for the power distribution system 8. The switch 16 receives the sensor output of the voltage sensor 14, closes when the grid connection is established, and opens when the grid power supply 10 is interrupted. The voltage sensor 14 and the switch 16 can be constituted by, for example, a relay solenoid and a normally closed contact. In other words, when the system is connected, the normally closed contact is closed by the excitation of the solenoid and the system power supply 10 is fed to the power distribution system 8, and when the power supply of the system power supply 10 is interrupted, the normally closed contact is opened by the solenoid excitation being released. Disconnect from system 8.

  The inverter (INV) 18 is connected to the power distribution system 8. The INV 18 converts AC input from the system power supply 10 into DC and feeds power to the storage battery 20 during grid connection, and converts DC output from the storage battery 20 into AC during a power failure.

  The storage battery 20 is charged by receiving the direct current output of the INV 18 at the time of grid connection, and outputs the direct current output, and outputs the stored power to the INV 18 at the time of a power failure.

  The FC system 6 is connected to the power distribution system 8, and generates power by power supply from the system power supply 10 when connected to the grid, and generates power by power supply from the power storage system 4 when the system power supply 10 fails. This generated power is supplied to the distribution system 8.

  The FC system 6 includes a power generation stack 22, an inverter (INV) 24, and a control unit 26. The power generation stack 22 receives voltage input from the distribution system 8 via the INV 24 and generates power.

  The INV 24 converts the direct current output of the power generation stack 22 into alternating current at the time of grid connection and at the time of power failure of the system power supply 10. The generated power of the FC system 6 is fed from the INV 24 to the distribution system 8.

  The control unit 26 is an example of a control unit, and is configured by a microcomputer, for example. The control unit 26 manages the grid connection protection function by monitoring the AC output from the INV 24 to the distribution system 8 and monitoring the grid connection, power failure, or power recovery. In this embodiment, the grid connection information, the power failure information, or the power recovery information is notified to the control unit 26 as monitoring information from the voltage sensor 14. The control unit 26 shifts to the operation at the time of grid connection by the grid connection information, the operation at the time of power failure by the power failure information, or the operation at the time of grid connection by the power recovery information.

  The grid connection protection function included in the control unit 26 includes an isolated operation detection function. This isolated operation detection function includes both a passive method and an active method. In this embodiment, the first protection condition is applied at the time of grid connection, and the second protection condition is applied at the time of a power failure of the system power supply 10. The first protection condition is applied at the time of grid connection as a strict protection condition for satisfying the grid connection regulations as described above. On the other hand, when the system power supply 10 fails and the system power supply 10 is disconnected, the second protection condition relaxed from the first protection condition is applied. This second protection condition includes condition relaxation or invalidation of the first protection condition. Then, when the system power supply 10 is restored, the second protection condition is switched to the first protection condition. That is, at the time of grid connection, the grid connection regulation is satisfied by returning to the first protection condition.

<Operation during grid connection>

In the power feeding system 2, as shown in FIG. 2A, the voltage sensor 14 detects the interconnection state of the system power supply 10, and the switch 16 is closed. Thereby, the system power Ps is supplied from the system power supply 10 to the power distribution system 8 and supplied to the power load 12. At this time, the power storage system 4 is charged, but the power Pb from the power storage system 4 is output to the power distribution system 8 and supplied to the power load 12. Further, the FC system 6 is supplied with power from the system power supply 10 to generate power, and the generated power Pg is output to the distribution system 8 and supplied to the power load 12. If the power supplied to the power load 12 is Pw1, the supplied power Pw1 is
Pw1≈Ps + Pb + Pg (1)
It becomes.

  During this grid connection, the grid connection information is notified from the voltage sensor 14 to the control unit 26. At this time, the control unit 26 applies the first protection condition as a strict protection condition for satisfying the grid interconnection regulations. That is, if the protection function operates, the FC system 6 stops power generation.

<Operation at power failure of system power supply 10>

  As shown in FIG. 2B, the voltage sensor 14 detects a power failure of the system power supply 10, and the switch 16 is opened. Thereby, the system power supply 10 is disconnected from the power distribution system 8. That is, the power feeding system 2 is disconnected from the system power supply 10 and shifts to the independent operation. The power storage system 4 outputs the power Pb to the power distribution system 8 and supplies it to the power load 12 and the FC system 6.

Further, the FC system 6 is supplied with power from the power storage system 4 and generates power, and the generated power Pg is output to the power distribution system 8 and supplied to the power load 12. In this case, if the power supplied to the power load 12 is Pw2, the supplied power Pw2 is Ps = 0.
Pw2≈Pb + Pg (2)
It becomes.

  At the time of this power failure, the control unit 26 is notified of power failure information from the voltage sensor 14. At this time, since the system power supply 10 is disconnected, the control unit 26 applies the second protection condition from the first protection condition described above. As a result, even if an instantaneous large current such as an inrush current is generated in the power load 12 and the current load on the FC system 6 side increases, the operation of the protection function such as isolated operation detection on the FC system 6 side is relaxed, The power generation output Pg is continuously output from the FC system 6 to the power distribution system 8 and supplied to the power load 12.

<Operation when system power supply 10 is restored>

  As shown in FIG. 2A, when the voltage sensor 14 detects the power recovery of the system power supply 10, the switch 16 is closed. Thereby, the disconnection of the system power supply 10 is canceled, and the system shifts to the grid interconnection operation. Thereby, the system power Ps is supplied from the system power supply 10 to the power distribution system 8 and supplied to the power load 12. As a result, the above-described power Pw1 (≈Ps + Pb + Pg) is supplied to the power load 12.

  At the time of power recovery, the control unit 26 is notified of power recovery information from the voltage sensor 14. At this time, the control unit 26 switches to the first protection condition as a strict protection condition for satisfying the grid interconnection regulations. That is, since the system is restored at the time of grid connection, the FC system 6 stops power generation if the protection function operates.

<Control function of FC system 6>

  FIG. 3 shows the control function of the FC system 6. The control unit 26 of the FC system 6 executes information processing by a computer, and this information processing includes a state determination function 30, a protection condition setting function 32, a protection condition switching function 34, an operation control function 36, and the like.

  The state determination function 30 determines the state of the system power supply 10. The state of the system power supply 10 includes grid connection, power failure, and power recovery from power failure. That is, the state determination function 30 is a state determination function for grid connection, power failure, and power recovery from a power failure. Therefore, the state determination function 30 receives the sensor output of the voltage sensor 14 as an example, and determines whether the system power supply 10 is in a connected state, a power failure state, or a state where power is restored from a power failure. This state determination may be made by receiving a sensor output from the voltage sensor 14 as in this embodiment, or may receive state information from the power storage system 4.

  The protection condition setting function 32 sets the first and second protection conditions described above. This protection condition is set to be selectable or switchable in the data table, for example.

  The protection condition switching function 34 switches the protection condition set by the protection condition setting function 32 from the current protection condition to another protection condition based on the determination result of the state determination function 30. The first protection condition is set at the time of grid connection. During a power failure, the first protection condition is switched to the second protection condition. When shifting from a power failure to power recovery, the second protection condition is switched to the first protection condition, thereby satisfying the grid interconnection regulations.

  The operation control function 36 performs operation control of the FC system 6 under the protection conditions being set. The FC system 6 operates under the first protection condition when the grid is connected or when power is restored from a power failure, and operates under the second protection condition during a power failure.

<Hardware of Control Unit 26>

  FIG. 4 shows an example of hardware of the control unit 26. The control unit 26 is configured by a computer. The control unit 26 includes, for example, a processor 40, a ROM (Read-Only Memory) 42, an NVM (Non Volatile Memory) 44, a RAM (Random-Access Memory) 46, and an input / output unit (I / O) 48. These functional units such as the processor 40 are connected by a bus 50.

  The processor 40 executes an OS (Operating System) in the ROM 42, executes a firmware program and an application program, and performs information processing and control including the above-described functions. The ROM 42 is an example of a program storage unit, and is configured by a storage medium such as a semiconductor storage element, for example. The ROM 42 stores an OS (Operating System), a firmware program, and an application program application. Various data is possible in the NVM 44, and a database is constructed. The NVM 44 is an example of a storage unit, and is composed of a nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory). The NVM 44 stores various types of control information such as setting information, and the control information includes the protection condition information described above, the grid connection protection function (detection condition) data table 52 (FIG. 5), An operation detection (passive method) condition data table 54 (FIG. 6) and an independent operation detection (active method) condition data table 56 (FIG. 7) are constructed. The RAM 46 forms a work area for information processing. The I / O 48 is used for setting information input and control output.

<System interconnection protection function (detection condition) data table 52>

  FIG. 5 shows an example of the grid connection protection function (detection condition) data table 52. In this grid connection protection function data table 52, a protection relay type 52-1, a standard set value 52-21, a condition relaxation set value 52-22, and a set value relationship definition 52-3 are set. An arrow 53 between the standard setting value 52-21 and the condition relaxation setting value 52-22 indicates a transition from the grid connection to the condition relaxation setting value 52-22 from the standard setting value 52-21 due to a power failure, or a power failure state. The transition from the condition relaxation set value 52-22 due to power recovery to the standard set value 52-21 is shown.

  In the protection relay type 52-1, the type information of the protection relay is set. This protection relay type includes overvoltage (OVR) 52-11, undervoltage (UVR) 52-12, frequency increase (OFR) 52-13, frequency decrease (UFR) 52-14, reverse power (RPR) 52-15, A reverse charge detection function 52-16 and an isolated operation detection function 52-17 are included. The reverse charge detection function 52-16 includes underpower (UPR) 52-161 and undervoltage (UVR) 52-162. The isolated operation detection function 52-17 includes a passive method 52-171 and an active method 52-172.

  The standard set value 52-21 is an example of a first protection condition. This standard settling value 52-21 includes a detection reference 52-211, and a detection time limit 52-212. The detection reference 52-211 of this embodiment includes overvoltage 52-11 = x1, undervoltage 52-12 = x2, frequency increase 52-13 = x3, frequency decrease 52-14 = x4, and reverse power 52-15 = x5, insufficient power 52-161 = x6, and insufficient voltage 52-162 = x7 are set. The detection time period 52-212 includes overvoltage 52-11 = t1, undervoltage 52-12 = t2, frequency increase 52-13 = t3, frequency decrease 52-14 = t4, reverse power 52-15 = t5, underpower 52 -161 = t6 and undervoltage 52-162 = t7 are set.

  The condition relaxation set value 52-22 is an example of a second protection condition. With this condition relaxation set value 52-22, the detection reference 52-221 includes overvoltage 52-11 = X1, undervoltage 52-12 = X2, frequency increase 52-13 = X3, frequency decrease 52-14 = X4, reverse power 52-15 = X5, insufficient power 52-161 = X6, and insufficient voltage 52-162 = X7 are set. The detection period 52-222 includes overvoltage 52-11 = T1, undervoltage 52-12 = T2, frequency increase 52-13 = T3, frequency decrease 52-14 = T4, reverse power 52-15 = T5, underpower 52 -161 = T6 and undervoltage 52-162 = T7 are set.

  These settling value relationship definitions 52-3 are: x1 ≦ X1, t1 ≧ T1, x2 ≧ X2, t2 ≧ T2, x3 ≦ X3, t3 ≧ T3, x4 ≧ X4, t4 ≧ T4, x5 ≦ X5, t5 ≧ T5, x6 ≦ X6, t6 ≧ T6, x7 ≧ X7, t7 ≧ T7. From such a relationship, the condition relaxation set value 52-22 is relaxed from the standard set value 52-21.

  <Single operation detection (passive method) condition data table 54>

  FIG. 6 shows an example of the isolated operation detection (passive method) condition data table 54. The isolated operation detection (passive method) condition data table 54 includes a passive method 54-1, a standard set value (detection condition) 52-21, a condition relaxation set value 52-22, and a settling value relationship definition 52-3. Is set.

  The passive method 54-1 includes voltage phase jump detection 54-11, third harmonic voltage distortion rapid increase detection 54-12, and frequency change rate detection 54-13.

  In detection standard 52-21 of standard settling value 52-21, voltage phase jump detection 54-11 = y11, third harmonic voltage distortion rapid increase detection 54-12 = y12, and frequency change rate detection 54-13 = y13 are set. ing.

  In the detection time limit 52-212 of the standard settling value 52-21, the voltage phase jump detection 54-11 = t11, the third harmonic voltage distortion rapid increase detection 54-12 = t12, and the frequency change rate detection 54-13 = t13 are set. ing.

  In the detection criterion 52-221 of the condition relaxation set value 52-22, the voltage phase jump detection 54-11 = Y11, the third harmonic voltage distortion rapid increase detection 54-12 = Y12, and the frequency change rate detection 54-13 = Y13 are set. Has been.

  In the detection time period 52-222 of the condition relaxation set value 52-22, the voltage phase jump detection 54-11 = T11, the third harmonic voltage distortion rapid increase detection 54-12 = T12, and the frequency change rate detection 54-13 = T13 are set. Has been.

  The relationship definition 52-3 of each setting value of these passive methods is y11 ≦ Y11, t11 ≧ T11, y12 ≦ Y12, t12 ≧ T12, y13 ≦ Y13, and t13 ≧ T13. From such a relationship, the condition relaxation set value 52-22 is relaxed from the detection level of the standard set value 52-21.

<Single operation detection (active method) condition data table 56>

  FIG. 7 shows an example of the independent operation detection (active method) condition data table 56. This isolated operation detection (active method) condition data table 56 includes an active method 56-1, a standard set value (detection condition) 52-21, a condition relaxation set value 52-22, and a settling value relationship definition 52-3. Is set.

  The active method 56-1 includes a frequency shift method 56-11, a slip mode frequency shift method 56-12, an active power fluctuation method 56-13, a reactive power fluctuation method 56-14, and a load fluctuation method 56-15.

  In the detection standard 52-211 of the standard setting value 52-21, the frequency shift method 56-11 = z 1, the slip mode frequency shift method 56-12 = z 2, the active power fluctuation method 56-13 = z 3, the reactive power fluctuation method 56- 14 = z4 and load variation method 56-15 = z5 are set.

  In the detection criteria 52-221 of the condition relaxation set value 52-22, the frequency shift method 56-11 = Z1, the slip mode frequency shift method 56-12 = Z2, the active power fluctuation method 56-13 = Z3, and the reactive power fluctuation method 56. -14 = Z4 and load variation method 56-15 = Z5 are set.

  The relationship definition 52-3 of the set values of these active methods is z1 ≦ Z1, z2 ≦ Z2, z3 ≦ Z3, z4 ≦ Z4, and z5 ≦ Z5. From such a relationship, the condition relaxation set value 52-22 is relaxed from the standard set value 52-21.

<Processing procedure>

  (1) When shifting from a grid connection state to a power failure

  FIG. 8 shows a processing procedure when shifting from a grid connection state to a power failure. This processing procedure is an example of the power supply control program and power supply control method of the power supply system of the present invention.

  This processing procedure includes a processing procedure on the power storage system 4 side and the FC system 6 side. In this processing procedure, power failure monitoring of the system power supply 10 is executed during grid connection (S101). In this power failure monitoring, it is determined whether or not the system power supply 10 has failed due to the sensor output of the voltage sensor 14 (S102). If the system power supply 10 has not failed (NO in S102), the power failure monitoring (S101) is continued.

  If it is a power failure (YES in S102), the switch 16 is opened (S103), and the system power supply 10 is disconnected from the distribution system 8.

  The sensor output of the voltage sensor 14 (system protection detection condition change command) is notified to the control unit 26 (S104).

  As a result, the control unit 26 changes the system protection detection condition from the standard set value to the condition relaxation set value (S105).

  The FC system 6 is operated by the system protection detection condition changed to the condition relaxation set value (S106).

  (2) When shifting from power failure to power recovery (system interconnection)

  FIG. 9 shows a processing procedure when shifting from a power failure state to power recovery. This processing procedure is an example of the power supply control program and power supply control method of the power supply system of the present invention.

  In the power failure state, power recovery monitoring of the system power supply 10 is executed (S111). In this power recovery monitoring, it is determined whether power has been recovered from the sensor output of the voltage sensor 14 (S112). If power is not restored (NO in S112), power recovery monitoring (S111) is continued.

  If power is restored (YES in S112), the switch 16 is closed (S113). As a result, the system power supply 10 is connected to the power distribution system 8 and power is supplied from the system power supply 10.

  The sensor output of the voltage sensor 14 (system protection detection condition change command) is notified to the control unit 26 (S114).

  Accordingly, the control unit 26 changes the system protection detection condition from the condition relaxation set value to the standard set value (S115).

  The FC system 6 is operated according to the system protection detection condition changed to the standard set value (S116).

<Effect of the first embodiment>

  In the first embodiment, the following effects can be obtained.

  (1) The voltage sensor 14 is provided as an example of the power failure detection means, and the power failure detection information is obtained from the voltage sensor 14. A switch 16 is provided, and the system power supply 10 is disconnected from the power storage system 4 and the FC system 6, which are distributed power supplies, based on the detection of a power failure by the voltage sensor 14. In a state where the system power supply 10 is disconnected, the system protection detection condition of the FC system 6 is changed, and the isolated operation detection condition is relaxed. When the islanding operation detection condition that is the system protection detection condition is relaxed, a voltage change that causes the FC system 6 to detect islanding operation when the system protection detection condition is the standard set value due to a sudden increase in load current of the power load 12 or the like. Even if it occurs, it is possible to avoid isolated operation detection. Thereby, a continuous power generation operation can be obtained, and the generated power can be supplied to the power load 12.

  (2) It is indispensable to provide an independent operation detection function for a distributed power source used for grid interconnection, and it is required to satisfy the grid interconnection regulations. However, it is not necessary to operate the isolated operation detection function in the disconnected state, and the function is in a stopped state. In other words, even if the islanding detection function is disabled, the system interconnection regulations are not violated. If the switch 16 that detects a power failure of the system power supply 10 and disconnects from the system power supply 10 is provided, when the switch 16 shifts to the open state, the distributed power source in the distribution system 8 in the disconnection state, for example, FC In the system 6, the isolated operation detection function becomes unnecessary. There is no problem even if the independent operation detection condition of the FC system 6 disconnected from the system power supply 10 is changed and relaxed or invalidated at the time of a power failure of the system power supply 10. On the FC system 6 side, free control can be performed, and the isolated operation detection of the FC system 6 can be avoided.

  In the FC system 6 that has shifted to such a control state, the FC system 6 detects the isolated operation even if the power quality 12 is degraded due to the power load 12 with the isolated operation detection condition that is the system protection detection condition changed. The power generation can be continued without any problem, and the power generated by the power feeding system 2 can be used.

[Second Embodiment]

<System configuration>

  FIG. 10 shows a power supply system according to the second embodiment. In the power feeding system 2 of this embodiment, a current sensor 58 and a control unit 60 are provided on the power storage system 4 side. The current sensor 58 is an example of a power supply sensor. When the power distribution system 8 is disconnected from the system power supply 10 by the switch 16, the current sensor 58 detects whether power is supplied from the power storage system 4 to the power distribution system 8 based on the presence or absence of current.

  Sensor outputs of the voltage sensor 14 and the current sensor 58 are applied to the control unit 60. The control unit 60 receives these sensor outputs and monitors the power supply from the power storage system 4 when the system power supply 10 fails. If power is not supplied from the power storage system 4 at the time of a power failure of the system power supply 10, the INV 18 is controlled to start feeding the storage battery 20 to the power distribution system 8.

  The controller 60 is linked to the controller 26 of the FC system 6. The controller 26 is notified from the controller 60 of the presence or absence of power supply of the power storage system 4. In this embodiment, the output of the voltage sensor 14 is input to the control unit 60. However, the configuration may be such that it is input to the control unit 26 as in the first embodiment. In any case, it is only necessary that the control unit 26 can recognize that there is power supply from the power storage system 4 at the time of a power failure of the system power supply 10.

<Control functions of power storage system 4 and FC system 6>

  FIG. 11 shows control functions of the power storage system 4 and the FC system 6. In this embodiment, the power storage system 4 includes a state monitoring function 62 and an output state monitoring function 64. The state monitoring function 62 monitors the sensor output of the voltage sensor 14 and determines each state of grid connection, power failure, or power recovery from the power failure as the state of the system power supply 10 from this sensor output. The monitoring output is notified from the power storage system 4 to the state determination function 30 of the FC system 6 by the notification function.

  The output state monitoring function 64 monitors the sensor output of the current sensor 58 and determines each state of the output state and the output release state as the state of the power storage system 4 from this sensor output. Since the current sensor 58 is installed in the distribution system 8, if the system power supply 10 is in a power feeding state, the current from the system power supply 10 is detected in the sensor output of the current sensor 58. However, if the system power supply 10 is disconnected, the output current of the power storage system 4 is detected by the current sensor 58. Then, the monitoring output of the output state monitoring function 64 is notified to the state determination function 30 of the FC system 6.

  In the state determination function 30 of this embodiment, it is determined from the monitoring outputs of both the state monitoring function 62 and the output state monitoring function 64 whether power is output from the power storage system 4 to the distribution system 8 at the time of a power failure. Can do. Thereby, appropriate control of protection condition change can be performed.

  Since the other functions are as described above, the same reference numerals are given and the description thereof is omitted.

<Processing procedure>

  (1) When shifting from a grid connection state to a power failure

  FIG. 12 shows a processing procedure when shifting from the grid connection state to a power failure. This processing procedure is an example of the power supply control program and power supply control method of the power supply system of the present invention.

  This processing procedure includes a control C1 on the power storage system 4 side and a control C2 on the FC system 6 side. In the power storage system 4, power failure monitoring of the system power supply 10 is executed during grid connection (S 201). In this power failure monitoring, it is determined whether or not the system power supply 10 has failed due to the sensor output of the voltage sensor 14 (S202). If the system power supply 10 has not failed (NO in S202), the power failure monitoring (S201) is continued.

  If it is a power failure (YES in S202), the switch 16 is opened (S203), and the system power supply 10 is disconnected from the distribution system 8.

  The output state monitoring of the power storage system 4 is executed (S204). In this output state monitoring, it is determined whether power is supplied from the storage battery 20 of the power storage system 4 (S205). For this determination, the sensor output of the current sensor 58 is referred to.

  If there is no power supply from the power storage system 4 (NO in S205), power is supplied from the storage battery 20 of the power storage system 4 (S206). This supply control is executed by the control unit 60.

  If there is power supply from the power storage system 4 (YES in S205), the control unit 60 notifies the control unit 26 of a control output (system protection detection condition change command) (S207).

  As a result, the control unit 26 changes the system protection detection condition from the standard set value to the condition relaxation set value (S208).

  The FC system 6 is operated according to the system protection detection condition changed to the condition relaxation set value (S209).

  (2) When shifting from power failure to power recovery (system interconnection)

  FIG. 13 shows a processing procedure when shifting from a power failure state to power recovery. This processing procedure is an example of the power supply control program and power supply control method of the power supply system of the present invention.

  In the power failure state, power recovery monitoring of the system power supply 10 is executed (S211). In this power recovery monitoring, it is determined whether power has been recovered from the sensor output of the voltage sensor 14 (S212). If power is not restored (NO in S212), power recovery monitoring (S211) is continued.

  If power is restored (YES in S212), the switch 16 is closed (S213). As a result, the system power supply 10 is connected to the power distribution system 8 and power is supplied from the system power supply 10.

  A control output (system protection detection condition change command) is notified from the control unit 60 to the control unit 26 of the FC system 6 (S214).

  As a result, the control unit 26 changes the system protection detection condition from the condition relaxation set value to the standard set value (S215).

  The FC system 6 is operated according to the system protection detection condition changed to the standard set value (S216).

<Effects of Second Embodiment>

  (1) According to the second embodiment, the continuity of power generation of the FC system 6 is enhanced as in the first embodiment, and the generated power for the power load 12 can be effectively used.

  (2) Since generated power is supplied from the FC system 6 to the power load 12, consumption of the storage battery 20 of the power storage system 4 can be reduced.

  (3) In this embodiment, since the control unit 26 changes the isolated operation detection condition through the control unit 60 of the power storage system 4, the operation and control on the power storage system 4 side and the operation and control on the FC system 6 side are performed. Can be made independent. Control reliability is increased.

[Other Embodiments]

  (1) In the first embodiment, the control unit 26 of the FC system 6 performs operation control on the FC system 6 side. However, as shown in FIG. The control unit 60 may be in charge.

  (2) In the second embodiment, the FC system 6 includes the control unit 26 and the power storage system 4 includes the control unit 60, and the protection condition is changed on the control unit 26 side, as shown in FIG. In addition, an external control unit 66 that cooperates with the control units 26 and 60 may be provided. The external control unit 66 may be constituted by a personal computer or the like, for example, hardware shown in FIG. The external control unit 66 may have the function shown in FIG. 3 or the function shown in FIG. Then, the change of the protection condition on the FC system 6 side and the control thereof may be performed by the external control unit 66. With such a configuration, the same effects as those of the above embodiment can be obtained.

  (3) As another embodiment, for example, as shown in FIG. 16, a switch 68 may be provided between the system power supply 10 and the input end of the power storage system 4. A system that can open the switch 68 and artificially disconnect the system power supply 10 from the power supply system 2 can be configured. For example, when the power load 12 is small, the power distribution system 8 can be disconnected from the system power supply 10 and the power load 12 can be supplied with power from the power supply system 2. In this case, the voltage sensor 14 is an example of a self-sustained operation detection unit of the power feeding system 2. That is, the voltage sensor 14 detects that the voltage input from the system power supply 10 has been released as a self-sustained operation detection in which the power feeding system 2 is disconnected from the system power supply 10. Based on this detection output, during the self-sustaining operation of the power feeding system 2, the same control as that at the time of the power failure of the system power supply 10 described above is performed. Since the details of the control contents are as described above, the description thereof is omitted.

  Even with such a configuration, a power supply system that can cope with a power failure can be configured by combining stationary power generation equipment such as the FC system 6 and the power storage system 4. And even if the voltage waveform is disturbed when the power load 12 suddenly changes, the stationary power generator can continue the operation without detecting the single operation, and the power generation output can be used effectively.

  (4) In the above-described embodiment, the second protection condition in which the first protection condition is relaxed is exemplified. However, the second protection condition may be a condition for invalidating the first protection condition.

  (5) In the above embodiment, the FC system 6 which is a stationary power generation device is exemplified as the distributed power source. However, sunlight such as a solar power generation system or an engine power generation system may be used.

As described above, the most preferable embodiment of the present invention has been described. The present invention is not limited to the above description. Various modifications and changes can be made by those skilled in the art based on the gist of the invention described in the claims or disclosed in the embodiments for carrying out the invention. It goes without saying that such modifications and changes are included in the scope of the present invention.

The present invention relates to a power feeding system, a power feeding control program, and a power feeding control method, which realizes continuous power generation by avoiding power generation stoppage due to isolated operation detection of stationary power generation equipment such as an FC system at the time of a power failure of a system power supply. In addition, continuous use and effective use of generated power can be achieved.

DESCRIPTION OF SYMBOLS 2 Power feeding system 4 Power storage system 6 FC system 8 Distribution system 10 System power supply 12 Power load 14 Voltage sensor 16 Switch 18 Inverter 20 Storage battery 22 Power generation stack 24 Inverter 26 Control part 30 State judgment function 32 Protection condition setting function 34 Protection condition switching function 36 Operation control function 40 Processor 42 ROM
44 NVM
46 RAM
48 Input / output unit 50 Bus 52 Grid connection protection function (detection condition) data table 52-1 Protection relay type 52-21 Standard set value 52-22 Condition relaxation set value 52-3 Setting value relationship definition 53 Arrow 52- 11 Overvoltage (OVR)
52-12 Undervoltage (UVR)
52-13 Frequency rise (OFR)
52-14 Frequency reduction (UFR)
52-15 Reverse Power (RPR)
52-16 Reverse charge detection function 52-161 Underpower (UPR)
52-162 Undervoltage (UVR)
52-17 Isolated Operation Detection Function 52-171 Passive Method 52-172 Active Method 52-221 Detection Criteria 52-212 Detection Period 54 Isolated Operation Detection (Passive Method) Condition Data Table 54-1 Passive Method 54-11 Voltage phase jump detection 52-12 Third harmonic voltage distortion rapid increase detection 54-13 Frequency change rate detection 56 Independent operation detection (active method) condition data table 56-1 Active method 56-11 Frequency shift method 56-12 Slip Mode frequency shift method 56-13 Active power fluctuation method 56-14 Reactive power fluctuation method 56-15 Load fluctuation method 58 Current sensor 60 Control unit 62 Status monitoring function 64 Output status monitoring function 66 External control unit 68 Switch

Claims (6)

Power storage means for supplying power stored by a system power supply to a power load at the time of a power failure of the system power supply, or supplying power to the power load at the time of a self-sustained operation at a non-power failure of the system power supply,
Power generation means for generating power by feeding power from the power storage means at the time of the power failure or the independent operation,
Detecting means for detecting the power failure or the autonomous operation;
A second protection condition different from the first protection condition is provided together with a first protection condition applied to the power generation means when the system power supply is connected, and the detection of the detection means is performed. Control means for switching from a protection condition to the second protection condition and applying the second protection condition to operate the power generation means;
A power supply system comprising:   The first protection condition and the second protection condition are detection conditions for an isolated operation of the power generation means, and the second protection condition is relaxed from the first protection condition, or the first protection condition The power supply system according to claim 1, wherein the protection condition is invalidated.   A storage means for storing the first protection condition and the second protection condition is provided, and the control means applies the first protection condition at the time of grid connection and receives the detection of the detection means. The power supply system according to claim 1, wherein the second protection condition is read from the storage unit, and the first protection condition is changed to the second protection condition.   An opening / closing means is provided between the system power supply and the power storage means, and when the system power supply is shut off from the power storage means by the opening / closing means, the control means detects the detection means or shuts off the opening / closing means. 4. The power generation means is operated by switching from the first protection condition to the second protection condition and applying the second protection condition based on both notifications. The power feeding system according to claim 1. A power storage means for supplying power to a power load at the time of a power failure of the system power supply, or a power storage means for supplying power to a power load at the time of a self-sustained operation at the time of non-power failure of the system power supply, A power supply control program for causing a computer mounted in a power supply system including power generation means to supply power to the power load,
When interconnecting the system power supply, a first protection condition applied to the power generation means, and a second protection condition different from the first protection condition are stored in the storage means,
When the power failure is detected or the autonomous operation is detected, the computer switches from the first protection condition to the second protection condition, and applies the second protection condition to operate the power generation unit. Power supply control program for A power storage means for supplying power to a power load at the time of a power failure of the system power supply, or a power storage means for supplying power to a power load at the time of a self-sustained operation at the time of non-power failure of the system power supply, A power supply control method comprising a power generation means for supplying generated power to the power load,
Detecting the power outage or the autonomous operation,
A second protection condition different from the first protection condition is set together with a first protection condition applied to the power generation means when the system power supply is interconnected;
Power supply control characterized by switching from the first protection condition to the second protection condition based on the detection of the power failure or the independent operation, and operating the power generation means by applying the second protection condition Method.

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