Protective device for 380V alternating-current power supply system for station

Abstract

The invention provides a protection device for a 380V alternating current power supply system for a station. The protection device comprises a CPU plug-in, an alternating current plug-in, a management plug-in, an input and output plug-in and a power supply plug-in, the alternating current plug-in unit is responsible for accessing system current, converting the system current into analog quantity signals and transmitting the analog quantity signals to the CPU plug-in unit; the input and output plug-in unit is used for acquiring circuit breaker position signals and transmitting the signals to the CPU plug-in unit; the CPU plug-in converts an analog quantity signal into a digital quantity signal, executes logic judgment and protection control of three-phase overcurrent protection and zero-sequence overcurrent protection, and monitors each interval state at the same time; when the input and output plug-in receives the protection tripping or alarm signal, the circuit breaker tripping and alarm device is driven. The management plug-in is responsible for data interaction with a scheduling end to realize management of system parameters and functions; and the power supply plug-in supplies power to each plug-in of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of protection of a 380V AC power supply system for a station, and in particular to a protection device for a 380V AC power supply system for a station. Background Art

[0002] The AC power supply used in traditional substations has a low level of intelligence, scattered protection configuration, and difficult level matching. It is impossible to achieve selectivity in protection actions during faults, and the risk of over-tripping is high, which puts great pressure on existing operation and maintenance work and is increasingly unable to meet current development requirements.

[0003] The current 380V power supply system for substations does not have independent microcomputer protection for the main incoming and main feeder lines. Instead, electronic trip devices are mostly used to implement protection functions. Although the wiring is simple, the large accuracy error makes it impossible to achieve differential coordination between the incoming line and the main feeder. When a fault occurs in the feeder line, over-tripping often occurs, resulting in a loss of voltage in the entire 380V busbar, and it is difficult to troubleshoot the fault point, which seriously affects the power supply safety of the substation. At the same time, it is difficult to calibrate the electronic trip device. Conventional protection devices can calibrate current accuracy and action time by applying secondary current, while electronic trip devices need to apply primary current, which is hundreds of amperes. The test equipment cannot apply stable large currents for a long time and frequently, so the action accuracy of its protection cannot be guaranteed. On-site maintenance is difficult, and it cannot meet the user's requirements for power supply safety of the power grid. Summary of the invention

[0004] The purpose of the present invention is to provide a station-based 380V AC power supply system protection device to achieve selectivity in 380V AC power supply system protection, while integrating multiple interval protections into one device, making full use of limited space to complete the installation of the protection device.

[0005] To achieve the above object, the present invention provides a station-use 380V AC power supply system protection device, comprising:

[0006] CPU plug-in, AC plug-in, management plug-in, input and output plug-in and power plug-in;

[0007] The AC plug-in is used to access the current of the incoming line interval, the outgoing line interval and the segment interval of the 380V AC power supply system for the station, and convert it into an analog signal and transmit it to the CPU plug-in;

[0008] The input and output plug-in is used to collect the circuit breaker position signal and transmit it to the CPU plug-in;

[0009] The CPU plug-in is used to convert the received analog signal into a digital signal, and perform logic judgment and protection control of the three-phase overcurrent protection and zero-sequence overcurrent protection of the incoming line interval, the outgoing line interval and the segment interval according to the digital signal and the circuit breaker position signal;

[0010] The input and output plug-in is used to output an electrical signal to the circuit breaker or the alarm device when receiving a protection trip or alarm signal sent by the CPU, so as to drive the circuit breaker to trip and the alarm device to alarm;

[0011] The CPU plug-in is also used to monitor the incoming line interval, the outgoing line interval and the segment interval according to the circuit breaker position signal output by the input and output plug-in and the voltage signal output by the AC plug-in;

[0012] The management plug-in is used to realize data interaction with the dispatching end and realize the management of system fixed value parameters, recording and LCD menu;

[0013] The power plug-in is used to provide power to each plug-in of the system.

[0014] Preferably, the CPU plug-in is used to monitor the digital current signal of the incoming line interval when the main power supply of the bus is the incoming line interval. If the three-phase current or zero-sequence current of the incoming line exceeds the preset protection setting, the delay timing is started. If the locking signal of the feeder line protection is not received within the set delay time, the CPU plug-in starts the three-phase overcurrent protection logic or zero-sequence overcurrent protection logic of the incoming line interval, and sends a tripping signal to the input and output plug-ins to control the circuit breaker of the incoming line interval to trip.

[0015] Preferably, the CPU plug-in is used to monitor the current digital signal of the feeder line interval when the main power supply of the bus is the incoming line interval. If the three-phase current or zero-sequence current of the feeder line exceeds the preset protection setting, the CPU plug-in starts the three-phase overcurrent protection logic or zero-sequence overcurrent protection logic of the feeder line interval, sends a tripping signal to the input and output plug-ins, controls the circuit breaker of the feeder line interval to disconnect and isolate the fault point, and at the same time, the CPU plug-in generates a locking signal for the feeder line protection.

[0016] Preferably, the CPU plug-in is used to monitor the current digital signal of the segmented interval when the main power supply of the bus is the segmented interval, and judge the circuit breaker position of the segmented interval and the incoming line interval according to the circuit breaker position signal provided by the input and output plug-in. If the circuit breaker of the segmented interval is closed and the circuit breaker of the incoming line interval is open, and the three-phase current or zero-sequence current of the feeder interval is greater than the preset protection setting, the CPU plug-in starts the three-phase overcurrent protection logic or zero-sequence overcurrent protection logic of the feeder interval, and sends a tripping signal to the input and output plug-in to control the circuit breaker of the incoming line interval to trip.

[0017] Preferably, the CPU plug-in is used to record relevant information of the protection action, including fault type, time, and current value, and upload the protection action record to the dispatching end through the management plug-in.

[0018] The 380V AC power supply system protection device for a station proposed by the present invention has the following beneficial effects:

[0019] A single device can realize the protection method of multiple incoming and outgoing line intervals of the entire busbar, saving the installation space of the device. The device can realize three-phase overcurrent protection and zero-sequence overcurrent protection for the incoming line interval, feeder line interval and segmented interval, ensuring the stability and safety of the power supply system; the analog signal is converted into a digital signal through the CPU plug-in, which can more accurately monitor the current and make logical judgments, thereby improving the accuracy and timeliness of the protection; when it is detected that the current exceeds the preset protection value, the CPU plug-in can quickly start the protection logic, and send a trip signal through the input and output plug-in to isolate the fault point in time and reduce the impact of the fault on the system; when the main power supply of the busbar is the incoming line interval, the CPU plug-in can monitor the protection locking signal of the feeder line interval to prevent false operation and improve the reliability of the system; the CPU plug-in can record the relevant information of the protection action and upload it to the dispatching end through the management plug-in, which is convenient for fault analysis and system maintenance; the management plug-in can realize data interaction with the dispatching end, which is convenient for the setting of system setting parameters, the viewing of recording data and the management of LCD menus, improving the operability and maintainability of the system; the power plug-in provides a stable power supply for each plug-in in the system, ensuring the reliable operation of the entire protection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

[0021] Figure 1 A schematic diagram of the main wiring of a 380V AC power supply system for a station connected to the protection device according to an embodiment of the present invention.

[0022] Figure 2 This is a protection logic diagram when the main power supply of the busbar in the embodiment of the present invention is the incoming line bay.

[0023] Figure 3 This is a protection logic diagram when the main power supply of the busbar in the embodiment of the present invention is a segmented interval. DETAILED DESCRIPTION

[0024] The detailed description of the drawings is intended as an illustration of the current embodiment of the present application, and is not intended to represent the only form in which the present application can be implemented. It should be understood that the same or equivalent functions can be accomplished by different embodiments intended to be included in the spirit and scope of the present application.

[0025] The embodiment of the present invention provides a 380V AC power supply system protection device for a station, Figure 1 The main wiring diagram of the station 380V AC power supply system connected to the protection device includes:

[0026] CPU plug-in, AC plug-in, management plug-in, input and output plug-in and power plug-in;

[0027] The AC plug-in is used to access the current of the incoming line interval, the outgoing line interval and the segment interval of the 380V AC power supply system for the station, and convert it into an analog signal and transmit it to the CPU plug-in;

[0028] The input and output plug-in is used to collect the circuit breaker position signal and transmit it to the CPU plug-in;

[0029] The CPU plug-in is used to convert the received analog signal into a digital signal, and perform logic judgment and protection control of the three-phase overcurrent protection and zero-sequence overcurrent protection of the incoming line interval, the outgoing line interval and the segment interval according to the digital signal and the circuit breaker position signal;

[0030] The input and output plug-in is used to output an electrical signal to the circuit breaker or the alarm device when receiving a protection trip or alarm signal sent by the CPU, so as to drive the circuit breaker to trip and the alarm device to alarm;

[0031] The CPU plug-in is also used to monitor the incoming line interval, the outgoing line interval and the segment interval according to the circuit breaker position signal output by the input and output plug-in and the voltage signal output by the AC plug-in;

[0032] The management plug-in is used to realize data interaction with the dispatching end and realize the management of system fixed value parameters, recording and LCD menu;

[0033] The power plug-in is used to provide power to each plug-in of the system.

[0034] The working principle of the device in this embodiment is as follows:

[0035] Current monitoring and signal conversion: The AC plug-in monitors the current of the power supply system and converts it into analog signals for transmission to the CPU plug-in. The CPU plug-in converts these analog signals into digital signals for more accurate logical judgment.

[0036] Protection logic judgment and control: The CPU plug-in performs logic judgment of three-phase overcurrent protection and zero-sequence overcurrent protection according to digital signals and circuit breaker position signals. If it is detected that the current exceeds the preset protection setting, the CPU plug-in will start the corresponding protection logic.

[0037] Circuit breaker control and alarm: When a protection action needs to be executed, the CPU plug-in sends a tripping signal through the input and output plug-ins to drive the circuit breaker to trip, thereby isolating the fault point. At the same time, if necessary, the input and output plug-ins can also drive the alarm device to issue an alarm.

[0038] System monitoring: The CPU plug-in uses the circuit breaker position signal provided by the input and output plug-in and the voltage signal provided by the AC plug-in to monitor each interval of the power supply system to ensure the normal operation of the system.

[0039] Data management and interaction: The management plug-in is responsible for data interaction with the dispatching end, so that the system's fixed value parameters, recorded data, LCD menu and other information can be effectively managed.

[0040] Further, see Figure 2 The CPU plug-in is used to monitor the current digital signal of the incoming line interval when the main power supply of the bus is the incoming line interval. If the three-phase current or zero-sequence current of the incoming line exceeds the preset protection setting, the delay timing is started. If the locking signal of the feeder line protection is not received within the set delay time, the CPU plug-in starts the three-phase overcurrent protection logic or zero-sequence overcurrent protection logic of the incoming line interval, and sends a tripping signal to the input and output plug-ins to control the circuit breaker of the incoming line interval to trip.

[0041] Specifically, when the main power supply of the busbar is the incoming line bay, the CPU plug-in will continuously monitor the current of the incoming line bay. What is monitored here is the digital signal of the current, which is converted by the AC plug-in from the analog signal of the current. The CPU plug-in will check whether the three-phase current or zero-sequence current of the incoming line bay exceeds the preset protection setting. These protection settings are set in advance to determine when the protection logic should be started. Once it is detected that the current exceeds the protection setting, the CPU plug-in will start a delay timer. The purpose of this delay timer is to confirm whether a lockout signal from the feeder line protection has been received. The lockout signal is a signal used to prevent false operation. It can indicate that other protection devices have detected a fault and are processing it.

[0042] During the delay timing, the CPU plug-in will wait for the lockout signal. If the lockout signal is received within this time, it means that other protection devices have responded to the fault, so the CPU plug-in does not need to take further action. If the lockout signal is not received within the set delay time, the CPU plug-in will believe that there may be a serious overcurrent fault in the incoming line interval, so it will start the three-phase overcurrent protection logic or zero-sequence overcurrent protection logic of the incoming line interval. After starting the protection logic, the CPU plug-in will send a trip signal to the input and output plug-ins. The function of this signal is to command the circuit breaker of the incoming line interval to trip, thereby cutting off the fault current and protecting other parts of the power supply system from the fault.

[0043] In this way, the CPU plug-in can effectively protect the incoming line interval to prevent equipment damage or system failure due to overcurrent. The delay timing setting can avoid false operation due to instantaneous current spikes or operating errors, ensuring the accuracy of protection and the stability of the system. For further information, see Figure 2 The CPU plug-in is used to monitor the current digital signal of the feeder line interval when the main power supply of the bus is the incoming line interval. If the three-phase current or zero-sequence current of the feeder line exceeds the preset protection setting, the CPU plug-in starts the three-phase overcurrent protection logic or zero-sequence overcurrent protection logic of the feeder line interval, sends a tripping signal to the input and output plug-ins, controls the circuit breaker of the feeder line interval to disconnect and isolate the fault point, and at the same time, the CPU plug-in generates a locking signal for the feeder line protection.

[0044] Specifically, when the main power supply of the busbar is the incoming line bay, the CPU plug-in continuously monitors the current of the feeder line bay. Here, the digital signal of the current is monitored. These signals are converted from the analog signal of the current by the AC plug-in. The CPU plug-in checks whether the three-phase current or zero-sequence current of the feeder line bay exceeds the preset protection setting value. These protection setting values ​​are pre-set to determine when the protection logic should be started. Once it is detected that the three-phase current or zero-sequence current of the feeder line bay exceeds the protection setting value, the CPU plug-in will start the corresponding three-phase overcurrent protection logic or zero-sequence overcurrent protection logic. This indicates that there may be a fault in the feeder line bay and protective measures need to be taken. After starting the protection logic, the CPU plug-in will send a trip signal to the input and output plug-in. The function of this signal is to command the circuit breaker of the feeder line bay to disconnect, thereby isolating the fault point, preventing the fault current from continuing to flow, and protecting other parts of the system from being affected. At the same time as sending the trip signal, the CPU plug-in will also generate a lock signal for the feeder line protection. The function of the blocking signal is to notify other protection devices in the system that the protection logic of the feeder interval has been triggered and there may be a fault. This can prevent other protection devices from malfunctioning due to the same fault.

[0045] In this way, the CPU plug-in can quickly respond to the overcurrent condition of the feeder interval, isolate the fault point in time, and prevent the fault from expanding. At the same time, the generation of the blocking signal ensures the coordination of the overall protection action of the system, avoiding unnecessary repeated actions or false actions.

[0046] Further, see Figure 3 The CPU plug-in is used to monitor the current digital signal of the segmented interval when the main power supply of the bus is the segmented interval, and judge the circuit breaker position of the segmented interval and the incoming line interval according to the circuit breaker position signal provided by the input and output plug-in. If the circuit breaker of the segmented interval is closed and the circuit breaker of the incoming line interval is open, and the three-phase current or zero-sequence current of the feeder interval is greater than the preset protection setting, the CPU plug-in starts the three-phase overcurrent protection logic or zero-sequence overcurrent protection logic of the feeder interval, and sends a trip signal to the input and output plug-in to control the circuit breaker of the incoming line interval to trip.

[0047] Specifically, when the main power supply of the busbar is the segmented interval, the CPU plug-in continuously monitors the current of the segmented interval. Here, the digital signals of the current are monitored, which are converted from the analog signals of the current by the AC plug-in. The CPU plug-in receives the circuit breaker position signals from the input and output plug-ins, which indicate whether the circuit breakers of the segmented interval and the incoming line interval are in the closed state or the open state. The CPU plug-in determines the circuit breaker position of the segmented interval and the incoming line interval according to the circuit breaker position signals provided by the input and output plug-ins. Specifically, it checks whether the circuit breaker of the segmented interval is closed and whether the circuit breaker of the incoming line interval is open. After confirming the position of the circuit breaker, the CPU plug-in checks whether the three-phase current or zero-sequence current of the feeder interval is greater than the preset protection setting. If the current exceeds this value, it indicates that there may be an overcurrent fault. If the circuit breaker of the segmented interval is closed, the circuit breaker of the incoming line interval is open, and the current of the feeder interval exceeds the protection setting, the CPU plug-in will start the three-phase overcurrent protection logic or the zero-sequence overcurrent protection logic of the feeder interval. After the protection logic is started, the CPU plug-in sends a trip signal to the input and output plug-in. The function of this signal is to command the circuit breaker in the incoming line bay to trip, thereby cutting off the fault current and protecting the system from overcurrent faults.

[0048] In this way, the CPU plug-in can ensure that the overcurrent fault of the feeder bay is handled in time when the main power supply of the busbar is a segmented bay. This protection mechanism can prevent equipment damage or system collapse caused by overcurrent faults and isolate the fault point by controlling the tripping of the circuit breaker in the incoming line bay.

[0049] Furthermore, the CPU plug-in is used to record relevant information of the protection action, including fault type, time, and current value, and upload the protection action record to the dispatching end through the management plug-in.

[0050] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A 380V AC power supply system protection device for a station, characterized in that: include: CPU plug-in, AC plug-in, management plug-in, input and output plug-in and power plug-in; The AC plug-in is used to access the current of the incoming line interval, the outgoing line interval and the segment interval of the 380V AC power supply system for the station, and convert it into an analog signal and transmit it to the CPU plug-in; The input and output plug-in is used to collect the circuit breaker position signal and transmit it to the CPU plug-in; The CPU plug-in is used to convert the received analog signal into a digital signal, and perform logic judgment and protection control of the three-phase overcurrent protection and zero-sequence overcurrent protection of the incoming line interval, the outgoing line interval and the segment interval according to the digital signal and the circuit breaker position signal; The input and output plug-in is used to output an electrical signal to the circuit breaker or the alarm device when receiving a protection trip or alarm signal sent by the CPU, so as to drive the circuit breaker to trip and the alarm device to alarm; The CPU plug-in is also used to monitor the incoming line interval, the outgoing line interval and the segment interval according to the circuit breaker position signal output by the input and output plug-in and the voltage signal output by the AC plug-in; The management plug-in is used to realize data interaction with the dispatching end and realize the management of system fixed value parameters, wave recording and LCD menu; The power plug-in is used to provide power to each plug-in of the system.

2. The protection device according to claim 1, characterized in that: The CPU plug-in is used to monitor the current digital signal of the incoming line interval when the main power supply of the bus is the incoming line interval. If the three-phase current or zero-sequence current of the incoming line exceeds the preset protection setting, the delay timing is started. If the locking signal of the feeder line protection is not received within the set delay time, the CPU plug-in starts the three-phase overcurrent protection logic or zero-sequence overcurrent protection logic of the incoming line interval, and sends a tripping signal to the input and output plug-ins to control the circuit breaker of the incoming line interval to trip.

3. The protection device according to claim 2, characterized in that: The CPU plug-in is used to monitor the current digital signal of the feeder line interval when the main power supply of the bus is the incoming line interval. If the three-phase current or zero-sequence current of the feeder line exceeds the preset protection setting, the CPU plug-in starts the three-phase overcurrent protection logic or zero-sequence overcurrent protection logic of the feeder line interval, sends a tripping signal to the input and output plug-ins, controls the circuit breaker of the feeder line interval to disconnect and isolate the fault point, and at the same time, the CPU plug-in generates a locking signal for the feeder line protection.

4. The protection device according to claim 3, characterized in that: The CPU plug-in is used to monitor the current digital signal of the segmented interval when the main power supply of the bus is the segmented interval, and judge the circuit breaker position of the segmented interval and the incoming line interval according to the circuit breaker position signal provided by the input and output plug-in. If the circuit breaker of the segmented interval is closed and the circuit breaker of the incoming line interval is open, and the three-phase current or zero-sequence current of the feeder interval is greater than the preset protection setting, the CPU plug-in starts the three-phase overcurrent protection logic or zero-sequence overcurrent protection logic of the feeder interval, and sends a trip signal to the input and output plug-in to control the circuit breaker of the incoming line interval to trip.

5. The protection device according to any one of claims 1 to 4, characterized in that: The CPU plug-in is used to record relevant information of the protection action, including fault type, time, and current value, and upload the protection action record to the dispatching end through the management plug-in.

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