JP4524057B2 - Charge / discharge system for secondary battery for power storage - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, when the commercial power system fails and the secondary battery for power storage is automatically disconnected (disconnected) from the power receiving facility, the secondary battery is removed under certain conditions after the commercial power system is restored. The present invention relates to a system that automatically parallelizes (connects) and automatically restarts charging / discharging operation.
[0002]
[Prior art]
The “Guidelines for grid interconnection technical requirements” issued by the government stipulates that “when an accident occurs in a grid system, the power generation equipment is disconnected from the grid and no single operation occurs”. Yes. Therefore, as described above, the secondary battery used in the power generation facility is automatically disconnected from the commercial power system when the commercial power system fails. Conventionally, the operation of re-paralleling to the system has been manually performed after the operation and maintenance staff has confirmed that there is no abnormality such as the secondary battery.
[0003]
However, if no operation and maintenance personnel are stationed locally, the secondary battery will be disconnected from the commercial power system until the operation and maintenance personnel arrive at the site even if the commercial power system recovers after a power failure. It is in the state. Therefore, when the power failure occurs in the secondary battery charging time zone, the amount of charge may be insufficient, and discharging may become impossible during the discharging time zone. On the other hand, in the discharge time zone of the secondary battery, the power discharged from the secondary battery is received from the commercial power system. Then, the electricity charge for the amount of power that was planned to be supplemented with the secondary battery is not only increased separately, but in some cases, it may exceed the contracted power with the power company. For this reason, it is desired that the secondary batteries be automatically arranged in parallel within a short time after power recovery.
[0004]
Here, the system of electricity charges will be briefly explained. When newly purchasing electricity from a domestic electric utility, the contract is usually made with the maximum power consumption (KW) as the contract power, and the contract power is not exceeded. As long as it is paid, a basic charge corresponding to the contract power and a charge for the amount of power used are paid every month. However, if it is recorded in the watt-hour meter that the average value of 30 minutes of electricity used exceeds the contracted electricity, a penalty is paid, or a higher basic charge with the excess electricity as the maximum electricity consumption is You have to pay for one year from the month.
[0005]
In addition, since the electric power used is usually low at night and increases during the day, there are contract types in which the electricity charge is set to be cheaper at night and higher during the day. Therefore, when a secondary battery for power storage is connected to a high-voltage power receiving facility, the secondary battery is charged in a time zone (generally late at night) when the electricity charge is cheap, and the power consumption is high and the electricity charge is expensive. Electricity is discharged during the time period to reduce the amount of power purchased during the expensive time period and lower the peak of power consumption, thereby reducing the contract power and lowering the payment fee.
[0006]
[Problems to be solved by the invention]
The present invention has been developed in consideration of the above circumstances, and its purpose is for power storage that can automatically arrange secondary batteries in parallel after the power recovery of the commercial power system even in the absence of operation maintenance personnel. It is providing the charging / discharging system of a secondary battery.
[0007]
[Means for Solving the Problems]
The present invention connects a power generation facility to a commercial power system through a power reception facility, and the power reception facility includes a system interconnection protection relay and a circuit breaker that opens with the power reception facility protection relay. Circuit breaker that opens at the power system protection relay and the power generation equipment protection relay, a secondary battery that charges and discharges from the commercial power system, and a monitor and control device that controls the charge and discharge.・ Understand power recovery based on the signal from the grid connection protection relay and grasp that the secondary battery is chargeable / dischargeable / impossible based on the signal from the power receiving equipment protection relay and the power generation equipment protection relay. In the power storage secondary battery charging / discharging system, when the commercial power system fails, the grid connection protection relay operates and the monitoring and control device opens both circuit breakers to automatically disconnect the secondary battery. Secondary power due to power failure When the commercial power system is restored after the power is disconnected, the monitoring and control device confirms that the commercial power system is restored and that the secondary battery can be charged / discharged. Measurement based on the signal from the power generation equipment protection relay, the measurement of the confirmation time to determine whether or not to reconnect the secondary battery is started, the power recovery status of the commercial power system and the secondary battery are charged. When the dischargeable state is maintained during the confirmation time, the monitoring and control device closes the disconnected circuit breaker after the confirmation time and automatically connects the secondary battery.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGS. 1 and 2, the charging / discharging system of the secondary battery for power storage according to the present invention connects a load facility 3 and a power generation facility 4 from a commercial power system (distribution line) 1 through a power receiving facility 2. is there.
[0009]
The power receiving facility 2 includes a high voltage power receiving panel 5 and a distribution board 6, and has a section switch 7 before entering the high voltage power receiving panel 5. In the high voltage power receiving panel 5, a high voltage circuit breaker 8 is provided on the main line. In addition to being connected, a branch is made before the high-voltage circuit breaker 8 to connect the grid interconnection protection relay 9, and an overcurrent protection relay 10 that opens the high-voltage circuit breaker 8 is connected to the vicinity of the high-voltage circuit breaker 8.
[0010]
In the distribution board 6, the trunk line is branched and connected to the load facility 3 and the power generation facility 4. One of the branch lines has a high-voltage circuit breaker 11 on the way to the load facility 3, and a power receiving facility protection relay 12 for the load facility is connected in the vicinity of the circuit breaker 11. Similarly, the other branch line includes a high-voltage circuit breaker 13 on the way to the power generation facility 4, and a power receiving facility protection relay 14 for the power generation facility is connected in the vicinity of the circuit breaker 13.
[0011]
The grid connection protection relay 9 includes an isolated operation detector, an overvoltage relay, an undervoltage relay, an overfrequency relay, an underfrequency relay, a ground fault overvoltage relay, and the like. Informs the power recovery.
[0012]
The power receiving equipment protection relay 14 includes a ground fault direction relay, an overcurrent relay, and the like, and outputs an open signal to a nearby power receiving equipment breaker 13 when an abnormality occurs.
[0013]
In the power generation equipment 4, a high-voltage circuit breaker 15 for power generation equipment is connected to a branch line in the high-voltage input panel, a power generation equipment protection relay 16 is connected in the vicinity of the circuit breaker 15, and then a transformer 17 is connected to the branch line. Are connected to the AC / DC converter panel. The power generation equipment protection relay 16 outputs an open signal to the nearby circuit breaker 15. In the AC / DC converter panel, low-voltage circuit breakers 18 and 20 are provided before and after the inverter 19, and finally led to the secondary battery 22. Since the secondary batteries 22 are connected in parallel, each battery includes a circuit breaker 21 on the secondary side of the low-voltage circuit breaker 20. In addition, a PCSCP (power control system computer) 23 is connected to the inverter 19, the low-voltage circuit breakers 18, 20 and the circuit breaker 21, and AC overcurrent, DC overcurrent, DC overvoltage, DC undervoltage, control power supply abnormality, fan abnormality Detecting stack temperature abnormality, fuse blown, stack arm short circuit, breaker trip, etc., it is judged whether the inverter 19 is operating normally or not, and whether the secondary battery 22 is normal or not. And the low-pressure circuit breakers 18 and 20 are automatically opened and closed by a signal from the monitoring control device 24.
[0014]
The supervisory control device 24 is connected to the grid connection protection relay 9, the power receiving equipment protection relay 14, the power generation equipment protection relay 16, the PCSCP 23, and the secondary battery 22. A charge command is given to the inverter 19 at night via the PCSCP 23. In the daytime, not only a discharge command is output, but also various signals are taken and an open / close signal is output to the circuit breakers 13, 15, 18, and 20 that disconnect the secondary battery. The monitoring control device 24 is also used for battery failure display, PCS failure display, grid connection protection relay 9 operation display, power receiving facility protection relay 14 operation display, power generation facility protection relay 16 operation display, and isolated operation detection display. It has a lamp and buzzer. Whether the secondary battery 22 is faulty or normal is detected by detecting battery voltage abnormal high, battery voltage abnormal low, battery current abnormal large, DC ground fault, battery temperature abnormal low, battery temperature abnormal high, battery control device abnormal, etc. To grasp.
[0015]
Further, in the supervisory control device 24, although not shown, a logic circuit that takes in signals from the grid interconnection protection relay 9, the power receiving equipment protection relay 14, and the power generation equipment protection relay 16, and an output signal from the logic circuit. A timer is provided to determine whether to reconnect the secondary battery 22 after a power failure.
[0016]
The logic circuit outputs a signal that prompts the timer to start measurement. The condition for the timer to start measurement is that when the power is restored after a power failure, a power recovery signal is output from the grid connection protection relay 9 and power is received. This is a time when a signal (non-operation signal) indicating a state in which charging / discharging is possible from the equipment protection relay 14 and the power generation equipment protection relay 16 to the secondary battery 22 is output. When an operation signal is output from the power receiving equipment protection relay 14 or the power generation equipment protection relay 16, the reconnection of the secondary battery 22 is postponed.
[0017]
The timer continues the measurement when the output of the signal prompting the start of measurement is continued, and the time during which the output continues is a confirmation time for determining whether or not to reconnect the secondary battery 22, for example, When 5 minutes have expired, a signal indicating the expiration is output to the main body of the supervisory control device, and when the expiration signal is received, the circuit breakers 13, 15, 18 and 20 that have disconnected the secondary battery 22 are closed. Is output, the breaker is closed, and the secondary battery 22 is automatically connected. In addition, if the power failure signal, the power receiving equipment protection relay 14 and the power generation equipment protection relay 16 are output to the logic circuit before the confirmation time expires, the measurement is stopped and the secondary battery 22 is disconnected. Maintain the state.
[0018]
The above-described charging / discharging system for the secondary battery for power storage, when an accident or the like occurs in the commercial power system 1 and a power failure occurs, the grid connection protection relay 9 operates and receives the operation signal (power failure signal). The control device 24 outputs an open signal to the circuit breakers 13, 15, 18, and 20 connected to the branch line leading to the secondary battery 22, and automatically opens the circuit breakers to indicate that a power failure has occurred. Expressed with a buzzer. Here, the reason why the low-voltage circuit breakers 18 and 20 are opened is to disconnect the inverter 19 from the circuit and prevent the secondary battery 22 from being charged and discharged.
[0019]
Further, when the accident is resolved and the commercial power grid 1 is restored, the grid interconnection protection relay 9 that has grasped the voltage / frequency of the commercial power grid 1 returns to the monitoring control device 24. Output. At this time, when receiving the non-operation signal from the power receiving equipment protection relay 14 and the non-operation signal from the power generation equipment protection relay 16 in addition to the power recovery signal (non-operation signal), the monitoring control device 24 generates a ground within the power generation equipment 4. It is determined that the secondary battery 22 is in a chargeable / dischargeable state by grasping that no entanglement or short circuit has occurred, and that the inverter 19 and the secondary battery 22 are normal. Until the power failure occurs, the circuit breakers 13, 15, 18, and 20 that disconnect the secondary battery 22 from the commercial power system 1 are all closed, and the secondary battery 22 and the inverter 19 are normal. If the monitoring control device 24 receives only the non-operation signal from the power receiving equipment protection relay 14, it can be determined that the secondary battery 22 is in a chargeable / dischargeable state. However, in order to make sure, the non-operation from the power generation equipment protection relay 16 A signal is also an element of judgment. Therefore, when receiving the power recovery signal, the non-operation signal from the power receiving equipment protection relay 14 and the non-operation signal from the power generation equipment protection relay 16, the monitoring control device 24 starts measuring the confirmation time and expires the confirmation time. However, when the state in which these signals are output is maintained, a closing signal is output to the circuit breakers 13, 15, 18, and 20 that have disconnected the secondary battery after the confirmation time has elapsed, and the circuit breakers are turned on. Close and reconnect the secondary battery 22 to resume charging and discharging.
[0020]
【The invention's effect】
According to the present invention, since the monitoring and control device automatically connects the secondary battery to the commercial power system after the power recovery, the charging and discharging of the secondary battery can be resumed quickly even when the operation maintenance staff is absent. it can. Therefore, the amount of charge and the amount of discharge are increased as compared with the conventional case, and the electricity bill can be reduced.
[Brief description of the drawings]
FIG. 1 is a simplified block diagram showing a charge / discharge system for a secondary battery for power storage according to the present invention.
FIG. 2 is a single-line diagram showing a charge / discharge system for a secondary battery for power storage according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Commercial power system 2 Power receiving equipment 4 Power generation equipment 9 System interconnection protection relays 13, 15, 18, 20 Circuit breaker 14 Power receiving equipment protection relay 16 Power generation equipment protection relay 22 Secondary battery 24 Monitoring and control device

Claims (1)

The power generation facility (4) is connected to the commercial power system (1) via the power receiving facility (2). In the power receiving facility (2), the grid interconnection protection relay (9) and the power receiving facility protection relay (14) are connected. An open circuit breaker (13) is provided, and in the power generation facility (4), there are a circuit breaker (15) opened by the grid interconnection protection relay (9) and the power generation facility protection relay (16), and a commercial power system (1). The secondary battery (22) that charges and discharges the battery and the monitoring and control device (24) that controls the charging and discharging of the secondary battery (22), the monitoring and control device (24) connects the power failure and power recovery of the commercial power system (1) to the system. From the power receiving equipment protection relay (14) and the power generation equipment protection relay (16), it is determined based on the signal from the system protection relay (9) and that the secondary battery (22) can be charged / discharged. Based on the signal, if the commercial power system fails, the grid connection protection relay (9) In the charge and discharge system to the monitoring control unit (24) is automatically disconnected power storage for a secondary battery of the secondary battery to open both breaker (13, 15) (22) operation,
When the commercial power system (1) recovers after the secondary battery (22) is disconnected due to a power failure, the supervisory control device (24) restores the commercial power system (1) and the secondary battery (22). Is recognized based on signals from the grid interconnection protection relay (9), the power receiving equipment protection relay (14), and the power generation equipment protection relay (16), the secondary battery (22 ) Is started to measure whether or not to connect again, and the power recovery state of the commercial power system (1) and the state where the secondary battery (22) can be charged and discharged are maintained during the confirmation time. Sometimes, the monitoring control device (24) closes the disconnected circuit breakers (13, 15) after the confirmation time elapses, and automatically connects the secondary battery (22). Charge / discharge system.

Images