What is the automatic control function of the monitoring system?
(1) Control function of computer monitoring system
The control function coverage of the computer monitoring system includes the solar photovoltaic power generation unit and the 10kV/110kV booster station system, and its monitoring function mainly includes the following points.
①Data acquisition and display Collect the real-time data and equipment operation status of the solar cell array, grid-connected inverter and booster station, and reflect the operation conditions with data and aspects through the local or remote display. The power frequency analog quantity of the 10kV system adopts AC sampling, and the state quantity adopts the method of empty contact to connect to the monitoring system. The 110kV system and the upper neck analog quantity of the main transformer body and various state quantities are directly connected to the monitoring system by digital signals.
②Safety monitoring automatically monitors the collected analog quantity, state quantity and protection information. When the measured limit exceeds the limit, the protection action, the abnormal state change, or the equipment is abnormal, it can sound local or distant in time. The alarm screen is launched, and the abnormal area is displayed. Accident information should be able to store and print records for subsequent analysis of the cause of the failure.
③Event sequence record When the photovoltaic power station system or equipment fails, the time sequence of abnormal state changes should be automatically recorded, stored, and transmitted remotely, and the event record resolution should be less than 1ms.
④Electric energy calculation It can realize the calculation of active and reactive power, time-sharing statistics of power amount, and statistical analysis of operating parameters.
⑤Control operation It can realize the closing and tripping control of the circuit breaker of the booster station, and the pulling and closing control of the neutral point isolation switch of the main transformer. And it has the function of preventing misoperation and the boost, buck and emergency stop control of the main transformer on-load voltage regulating switch. Each PV grid-connected inverter can be individually parameterized and set to start and stop.
⑥Remote communication and data exchange with the protection device to issue the command of time synchronization and call data to the protection device of the booster station, and transmit the new protection setting value: the protection device reports the protection action parameters (action time, action nature, action value, action name, etc.).
⑦ There are three ways to manage the automation device:
a. Realize human-computer interaction through the liquid crystal display and keyboard of each device;
b. Realize human-computer interaction through the local monitoring and management system of the booster station:
c. Realize human-computer interaction through remote dispatch master station.
⑧ There are three ways to control:
a. On-site manual control at the equipment installation site:
b. Button control of the human-computer interaction screen of the local monitoring and management system of the booster station;
c. Scheduling remote master station remote control.
The above three control operations need to be locked with each other, and only one control command is received at the same time.
⑨ Remote control function The computer monitoring system is equipped with a remote control station, through which the functions of telemetry, remote signaling, remote control, and remote adjustment with the ground adjustment can be realized.
⑩Other functions The computer monitoring system has the function of time recording and remote transmission. The clock can be calibrated by GPS. It has a standard communication protocol and has multiple remote interfaces. If necessary, it obeys the communication protocol of the master station to carry out unconventional data communication.
(2) Functions of microcomputer protection and automation devices
①Main transformer protection
a. Differential protection
The protection action trips the circuit breakers on both sides of the main transformer. When the differential secondary circuit is disconnected, the differential protection is closed.
b. Gas protection
The heavy gas protection action trips the circuit breakers on both sides of the main transformer, and the light gas action sends a signal.
c. Main transformer on-load tap-changer gas protection
The heavy gas protection action trips the circuit breakers on both sides of the main transformer, and the light gas action sends a signal.
d. Release protection
The protection action trips the circuit breakers on both sides of the main transformer.
e. Backup protection
·The 110kV side is equipped with compound voltage starting overcurrent protection, the protection has a time limit of I stage, and the circuit breakers on both sides of the main transformer are tripped after the delay action.
·The neutral point of the 110kV side is equipped with zero-sequence overcurrent protection. The protection is a one-stage type without directional element blocking. As the total backup section of the transformer, the protection action will trip the circuit breakers on both sides of the transformer after a delay.
The neutral point of 110kV side is equipped with gap zero-sequence current and voltage protection that is not directly grounded. When a ground fault occurs in the system, the discharge gap discharges, and the transformer is cut off from the faulty grid through zero-sequence overcurrent protection, and the protection action is delayed ( 0.3~0.5s) trip the circuit breakers on both sides of the main transformer. If the discharge gap is not broken down. Then the zero-sequence voltage protection will act, and the circuit breakers on both sides of the main transformer will be tripped after a delay (0.3~0.5s).
·The main transformer l0kV side is equipped with compound voltage starting overcurrent protection. The protection zone has a time limit of section I, and the circuit breakers on both sides of the main transformer are tripped after the delay action.
f. Main transformer overload protection Overload protection is installed on both sides of the main transformer, with three-stage time limit, the first stage time limit sends a signal, the second stage time limit starts the fan, and the third stage time limit stops the on-load voltage regulation.
②110kV line protection device 110kV line protection is equipped with current quick-break protection, overcurrent protection, three-phase one-time reclosing, low-current grounding automatic line selection, overload alarm, etc.
③ l0kV station use and low-voltage transformer protection 1l0V low-voltage transformer can be equipped with current quick-break, over-current protection and non-electrical protection.
④The 0.38kV incoming circuit breaker measurement and control device needs to be equipped with a measurement and control device for the 380V incoming circuit breaker.
⑤Anti-misoperation locking A set of computer anti-misoperation operating system is used in the whole station. The system communicates with the computer monitoring system, and can perform five anti-operation blocking for circuit breakers, isolating switches, grounding switches and net gates in the booster station.
⑥GPS system A set of GPS device is installed in the whole station to provide a time reference for the equipment (measurement and control device, relay protection and safety automatic device, etc.) that need accurate time for operation in the station.