New energy power station single-phase earth fault comprehensive protection system and method

Abstract

The invention relates to the field of power system protection, and discloses a new energy power station single-phase earth fault comprehensive protection system and method, and the system comprises a line remote measurement module which is used for detecting the current and voltage of each line in a power station; the comprehensive grounding protection equipment is used for switching to a corresponding mode according to a neutral point setting mode of the power station; based on the current and voltage of each line and the opening and closing position state of a circuit breaker in the power station, whether a grounding fault occurs is judged through logical operation; sending a corresponding control signal according to a judgment result; the automatic circuit breaker device is connected to a grounding branch of a power station in series, and when the automatic circuit breaker device receives a control signal, the automatic circuit breaker device is switched on or switched off, so that the power station operates in a grounding mode or a non-grounding mode, and the problems that an existing grounding protection device is limited in application range and limited in function, and an original line protection device does not operate are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power system protection, in particular to a single-phase grounding fault comprehensive protection system and method for new energy power station. BACKGROUND

[0002] With the rapid development of new energy, the scale of wind and photovoltaic power generation gradually increases, and new energy occupies an increasingly important position in the field. However, the single-phase grounding fault has the highest failure rate in the current new energy power station, with a failure rate of 60% to 70%, and the fault may be caused by single-phase grounding of the transmission line, breakdown of the insulation component, etc. Once the line is grounded due to single-phase fault, the line protection device acts, the corresponding circuit breaker trips, and the single-phase grounding fault is eliminated. However, the current single-phase grounding fault removal device has the following problems: (1) Limited application range: Conventional new energy power stations are divided into two design modes, with and without main transformers. These two design modes have their own characteristics, and there is currently no grounding fault protection system that can integrate the two different design modes, greatly reducing the versatility of the device. The device system can complete the design mode of different power stations.

[0003] (2) Limited function: The current grounding protection device cannot automatically switch the grounding resistance operation mode, and the manual mechanical operation of the isolation switch makes it difficult to switch the grounding resistance operation mode in time when a single-phase grounding fault occurs, which may cause continuous current to burn out the resistor and cause significant economic losses.

[0004] The original line protection device as a remote backup protection refuses to act: When a single-phase grounding fault occurs, the original line protection refuses to act, making it difficult to remove the single-phase grounding fault, which may cause the fault to further expand and cause significant economic losses. The device can act on the circuit breaker again, so that the device is disconnected, i.e., when the circuit breaker at the small resistor is cut off, it becomes a non-grounding system, at which point the protection device will no longer function and protect the grounding fault. The device can still work after the circuit breaker at the small resistor is disconnected. SUMMARY

[0005] Therefore, the present application provides a single-phase grounding fault comprehensive protection system and method for new energy power station to solve the problems of limited application range, limited function, and refusal of the original line protection device to act.

[0006] In a first aspect, the present application provides a new energy power station single-phase grounding fault comprehensive protection system, comprising: a line telemetry module, a comprehensive grounding protection device, and an automatic circuit breaker device, wherein the line telemetry module is used to detect the current and voltage of each line in the power station; the comprehensive grounding protection device is used to switch to a corresponding mode according to the neutral point setting mode of the power station; based on the current and voltage of each line and the on-off position state of the circuit breaker in the power station, logical operation is performed to determine whether a grounding fault occurs; a corresponding control signal is sent according to the determination result; and the automatic circuit breaker device is connected in series to the grounding branch of the power station, and when the automatic circuit breaker device receives the control signal, it is closed or opened to realize the operation of the power station in the grounding mode or the non-grounding mode.

[0007] The present application switches different working modes according to the neutral point setting mode, and realizes the grounding protection of multiple lines based on the current and voltage of each line and the on-off position state of the circuit breaker in the power station, thereby solving the problems of limited application range, limited function and original line protection device refusal of the existing grounding protection device.

[0008] In an optional embodiment, the comprehensive grounding protection device comprises: an analog signal input module, a switching signal input module, an analog-to-digital conversion module, a logic judgment module, a switching signal output module, a mode conversion module, and a man-machine interaction module, wherein the analog signal input module is used to collect the current and voltage signals of the current transformer and the voltage transformer, and transmit the current and voltage signals to the analog-to-digital conversion module; the switching signal input module is used to collect the on-off position state of the corresponding circuit breaker, and transmit the on-off position state of the circuit breaker to the logic judgment module; the analog-to-digital conversion module is used to convert the analog signal of the analog signal input module into a digital signal, and transmit the digital signal to the logic judgment module; the logic judgment module compares the amplitude and phase based on the current and voltage of each line obtained by the line telemetry module, and at the same time, combines the on-off position state of the circuit breaker to determine whether a grounding fault occurs through logical operation; the switching signal output module is used to receive the logic judgment result of the logic judgment module, and is used to output a corresponding circuit breaker control signal; the mode conversion module is used to switch the working mode of the comprehensive grounding protection device according to the neutral point setting mode of the power station; and the man-machine interaction module is used for human control and searching of the operation state of the system, and the working mode switching of the mode conversion module is realized by the man-machine interaction module.

[0009] In an optional embodiment, the working mode comprises: a new energy power station with a small resistance grounding mode through a grounding transformer without main transformer voltage boosting, a new energy power station with a main transformer low voltage side neutral point resistance grounding mode through a main transformer voltage boosting, and a new energy power station with a small resistance grounding mode through a grounding transformer with a main transformer voltage boosting.

[0010] In a second aspect, the present application provides a new energy power station single-phase grounding fault comprehensive protection method, which is applied to the comprehensive grounding protection device of the second optional implementation of the first aspect, and the method comprises the following steps: acquiring the current and voltage of each line in the power station detected by a line telemetering module; switching to a corresponding mode according to the neutral point setting mode of the power station; judging whether a grounding fault occurs through logical operation based on the amplitude and phase of the current and voltage of each line, the on-off position state of the circuit breaker of the power station, and issuing a corresponding control signal according to the judgment result; and the control signal is used to control the on-off of the automatic circuit breaker device to realize the operation of the power station in the grounded mode or the ungrounded mode.

[0011] In an optional implementation, the power station comprises a power collection line, a grounding line, a grounding transformer branch, a sending-out line, a bus and other lines.

[0012] In an alternative embodiment, for any bus line, the process of issuing a corresponding control signal according to the judgment result comprises: when the working mode is the new energy power station without main transformer step-up through grounding transformer small resistance grounding mode, if the bus zero sequence voltage amplitude is greater than or equal to the preset bus voltage threshold value, the zero sequence current amplitude on the grounding line is greater than or equal to the preset grounding current threshold value, the zero sequence current amplitude of the grounding transformer branch is greater than or equal to the preset grounding transformer current threshold value, and the zero sequence current amplitude of the bus line is greater than or equal to the preset bus line current threshold value, the automatic circuit breaker device is controlled to be tripped; after a preset time, if the bus zero sequence voltage amplitude is greater than or equal to the preset bus voltage threshold value, the automatic circuit breaker device is controlled to remain in the tripped state, and the circuit breaker on the bus line is controlled to be disconnected, otherwise the automatic circuit breaker device is controlled to be closed; when the working mode is the new energy power station with main transformer step-up through main transformer low voltage side neutral point resistance grounding mode, if the bus zero sequence voltage amplitude is greater than or equal to the preset bus voltage threshold value, the zero sequence current amplitude on the grounding line is greater than or equal to the preset grounding current threshold value, the zero sequence current amplitude of the outgoing line is greater than or equal to the preset grounding transformer current threshold value, and the zero sequence current amplitude of the bus line is greater than or equal to the preset bus line current threshold value, the automatic circuit breaker device is controlled to be tripped; after a preset time, if the bus zero sequence voltage amplitude is greater than or equal to the preset bus voltage threshold value, the automatic circuit breaker device is controlled to remain in the tripped state, and the circuit breaker on the bus line is controlled to be disconnected, otherwise the automatic circuit breaker device is controlled to be closed; when the working mode is the new energy power station with main transformer step-up through grounding transformer small resistance grounding mode, if the bus zero sequence voltage amplitude is greater than or equal to the preset bus voltage threshold value, the zero sequence current amplitude on the grounding line is greater than or equal to the preset grounding current threshold value, the zero sequence current amplitude of the grounding transformer branch is greater than or equal to the preset grounding transformer current threshold value, and the zero sequence current amplitude of the bus line is greater than or equal to the preset bus line current threshold value, the automatic circuit breaker device is controlled to be tripped; after a preset time, if the bus zero sequence voltage amplitude is greater than or equal to the preset bus voltage threshold value, the automatic circuit breaker device is controlled to remain in the tripped state, and the circuit breaker on the bus line is controlled to be disconnected, otherwise the automatic circuit breaker device is controlled to be closed.

[0013] In an alternative embodiment, the process of issuing corresponding control signals according to the judgment result when at least one current collecting circuit has a permanent single-phase ground fault further comprises: for any current collecting circuit that is not faulty, if the bus zero sequence voltage amplitude is greater than or equal to a preset bus voltage threshold, the zero sequence current amplitude of the current collecting circuit is greater than or equal to a preset current collecting circuit current threshold, and the phase angle of the current collecting circuit is greater than or equal to -180° and less than or equal to 0°, then controlling the circuit breaker on the current collecting circuit to open; for any other circuit, if the bus zero sequence voltage amplitude is greater than or equal to a preset bus voltage threshold, the zero sequence current amplitude of the other circuit is greater than or equal to a preset other circuit current threshold, and the phase angle of the other circuit is greater than or equal to -180° and less than or equal to 0°, then controlling the circuit breaker on the other circuit to open.

[0014] In an alternative embodiment, the process of issuing corresponding control signals according to the judgment result further comprises: if the bus zero sequence voltage amplitude is greater than or equal to a preset bus voltage threshold, the zero sequence current amplitude of the outgoing circuit is greater than or equal to a preset outgoing circuit current threshold, the zero sequence current amplitude of the ground transformer branch is greater than or equal to a preset ground transformer current threshold, the zero sequence current amplitudes of all current collecting circuits are greater than or equal to a current collecting circuit current threshold, and the phase angles of the outgoing circuit, the ground transformer branch, and all current collecting circuits are greater than or equal to -180° and less than or equal to 0°, then controlling the circuit breakers on the outgoing circuit, the ground transformer branch, and all current collecting circuits to open.

[0015] In an alternative embodiment, for any other line, the process of issuing corresponding control signals according to the judgment result comprises: when the working mode is the new energy power plant without step-up of main transformer and with small resistance grounding mode of grounding transformer, if the amplitude of bus zero sequence voltage is greater than or equal to the preset bus voltage threshold, the amplitude of zero sequence current on the grounding line is greater than or equal to the preset grounding current threshold, the amplitude of zero sequence current of the grounding transformer branch is greater than or equal to the preset grounding transformer current threshold, and the amplitude of zero sequence current of the other line is greater than or equal to the preset current threshold of the current collection line, the automatic circuit breaker device is controlled to be tripped; after a preset time, if the amplitude of bus zero sequence voltage is greater than or equal to the preset bus voltage threshold, the automatic circuit breaker device is controlled to remain in the tripped state, and the circuit breaker on the other line is controlled to be disconnected, otherwise the automatic circuit breaker device is controlled to be closed; when the working mode is the new energy power plant with step-up of main transformer and with neutral point resistance grounding mode of low voltage side of main transformer, if the amplitude of bus zero sequence voltage is greater than or equal to the preset bus voltage threshold, the amplitude of zero sequence current on the grounding line is greater than or equal to the preset grounding current threshold, the amplitude of zero sequence current of the outgoing line is greater than or equal to the preset grounding transformer current threshold, and the amplitude of zero sequence current of the other line is greater than or equal to the preset current threshold of the current collection line, the automatic circuit breaker device is controlled to be tripped; after a preset time, if the amplitude of bus zero sequence voltage is greater than or equal to the preset bus voltage threshold, the automatic circuit breaker device is controlled to remain in the tripped state, and the circuit breaker on the other line is controlled to be disconnected, otherwise the automatic circuit breaker device is controlled to be closed; when the working mode is the new energy power plant with step-up of main transformer and with small resistance grounding mode of grounding transformer, if the amplitude of bus zero sequence voltage is greater than or equal to the preset bus voltage threshold, the amplitude of zero sequence current on the grounding line is greater than or equal to the preset grounding current threshold, the amplitude of zero sequence current of the grounding transformer branch is greater than or equal to the preset grounding transformer current threshold, and the amplitude of zero sequence current of the other line is greater than or equal to the preset current threshold of the current collection line, the automatic circuit breaker device is controlled to be tripped; after a preset time, if the amplitude of bus zero sequence voltage is greater than or equal to the preset bus voltage threshold, the automatic circuit breaker device is controlled to remain in the tripped state, and the circuit breaker on the other line is controlled to be disconnected, otherwise the automatic circuit breaker device is controlled to be closed.

[0016] In an alternative embodiment, when at least one other line has a permanent single-phase grounding fault, the process of issuing corresponding control signals according to the judgment result further comprises: for any current collection line, if the amplitude of bus zero sequence voltage is greater than or equal to the preset bus voltage threshold, the amplitude of zero sequence current of the current collection line is greater than or equal to the preset current threshold of the current collection line, and the phase angle of the current collection line is greater than or equal to -180° and less than or equal to 0°, the circuit breaker on the current collection line is controlled to be disconnected.

[0017] In an alternative embodiment, the process of issuing the corresponding control signal according to the judgment result further comprises: if the bus zero sequence voltage amplitude is greater than or equal to a preset bus voltage threshold, the zero sequence current amplitude of the outgoing line is greater than or equal to a preset outgoing line current threshold, the zero sequence current amplitude of the grounding transformer branch is greater than or equal to a preset grounding transformer current threshold, the zero sequence current amplitudes of all the collector lines are greater than or equal to a collector line current threshold, and the phase angles of the outgoing line, the grounding transformer branch and all the collector lines are greater than or equal to -180° and less than or equal to 0°, then controlling the circuit breakers on the outgoing line, the grounding transformer branch and all the collector lines to open.

[0018] In an alternative embodiment, for the grounding transformer line, the process of issuing the corresponding control signal according to the judgment result comprises: if the bus zero sequence voltage amplitude is greater than or equal to a preset bus voltage threshold, and the zero sequence current amplitude of the grounding line is greater than or equal to a preset grounding current threshold, then controlling the automatic circuit breaker device to remain in the open state, and after a preset time, controlling the circuit breaker on the grounding transformer line to open; if the difference between the amplitude of any one phase current of the bus and the zero sequence current amplitude thereof is greater than or equal to a preset current difference, then controlling the circuit breaker on the grounding transformer line to open.

[0019] In a third aspect, the present application provides a computer device, comprising: a memory and a processor, which are communicatively connected with each other, and the memory stores computer instructions; the processor executes the computer instructions to perform the new energy power station single-phase grounding fault comprehensive protection method of the second aspect or any of the corresponding embodiments thereof.

[0020] In a fourth aspect, the present application provides a computer readable storage medium, which stores computer instructions, and the computer instructions are used to make a computer execute the new energy power station single-phase grounding fault comprehensive protection method of the second aspect or any of the corresponding embodiments thereof.

[0021] In a fifth aspect, the present application provides a computer program product, which comprises computer instructions, and the computer instructions are used to make a computer execute the new energy power station single-phase grounding fault comprehensive protection method of the second aspect or any of the corresponding embodiments thereof. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0023] Figure 1is a specific structural diagram of an automatic circuit breaker device according to an embodiment of the present application; Figure 2 is a specific structural diagram of a comprehensive ground protection device according to an embodiment of the present application; Figure 3 is a specific structural diagram of an analog signal input module, a switching signal input module and a switching signal output module according to an embodiment of the present application; Figure 4 is a schematic diagram of a mode conversion module and a logic judgment module according to an embodiment of the present application; Figure 5 is a flowchart of a ground fault comprehensive protection method according to an embodiment of the present application; Figure 6 is a structure schematic diagram of a new energy power station without main transformer step-up through a small resistance grounding mode-grounding protection system according to an embodiment of the present application; Figure 7 is a structure schematic diagram of a new energy power station with main transformer step-up through a low voltage side neutral point resistance grounding mode-grounding system protection according to an embodiment of the present application; Figure 8 is a structure schematic diagram of a new energy power station with main transformer step-up through a small resistance grounding mode-grounding system protection according to an embodiment of the present application; Figure 9 is a hardware structure schematic diagram of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0025] In the present embodiment, a new energy power station single-phase ground fault comprehensive protection system is provided, comprising: a line telemetry module, a comprehensive ground protection device, and an automatic circuit breaker device.

[0026] Specifically, the line telemetry module is configured to detect the current and voltage of each line in the power station; the line telemetry module comprises current transformers and voltage transformers arranged on each line, which are configured to detect the current and voltage of the corresponding line and transmit the corresponding current signal and voltage signal to the comprehensive ground protection device.

[0027] Specifically, the integrated grounding protection device is used to switch to a corresponding mode according to a neutral point setting mode of the power station; based on currents and voltages of each line and a position state of a circuit breaker of the power station, whether a grounding fault occurs is determined through logical operation; and a corresponding control signal is sent according to a determination result.

[0028] Specifically, the automatic circuit breaker device is connected into a grounding branch of the power station, and when the automatic circuit breaker device receives a control signal, the automatic circuit breaker device is closed or opened to realize grounding mode or non-grounding mode operation of the power station. Optionally, as shown in Figure 1 the automatic circuit breaker device includes a circuit breaker (i.e., DL) and a disconnector (i.e., GL), and the disconnector is used to open / close a grounding transformer branch. When the disconnector is in a closed position, it indicates that the line is connected, and the system is in a small-resistance grounding mode; when the disconnector is in an open position, it indicates that the line is disconnected, and the system is in a non-grounding mode.

[0029] In some optional embodiments, as shown in Figure 2 the integrated grounding protection device includes an analog signal input module, a switching signal input module, an analog-digital conversion module, a logic judgment module, a switching signal output module, a mode conversion module, and a human-computer interaction module.

[0030] Specifically, the analog signal input module is used to collect current and voltage signals of current transformers and voltage transformers, and transmit the current and voltage signals to the analog-digital conversion module; as shown in Figure 3 the analog signal input module includes a plurality of analog signal input interfaces, an analog signal input first interface to an analog signal input tenth interface, each interface corresponds to a different analog signal source, that is, a current transformer and a voltage transformer at a different position, and the number of analog signal input interfaces can be increased according to a requirement of the device.

[0031] Specifically, the switching signal input module is used to collect a circuit breaker opening / closing position state of a corresponding circuit breaker, and transmit the circuit breaker opening / closing position state to the logic judgment module; as shown in Figure 3 the switching signal input module includes a plurality of switching signal input interfaces, a switching signal input first interface to a switching signal input tenth interface, each interface corresponds to a “opening / closing” state of a circuit breaker at a different position, and is used to collect the “opening / closing” state of the circuit breaker in real time.

[0032] Specifically, the analog-digital conversion module is used to convert analog signals of the analog signal input module into digital signals, and transmit the digital signals to the logic judgment module.

[0033] Specifically, the logic judgment module judges whether a ground fault occurs according to the current and voltage of each line obtained by the line telemetry module, compares the amplitude and phase, and combines the opening and closing position state of the circuit breaker to perform logic operation; the switch signal output module receives the logic judgment result of the logic judgment module, outputs the corresponding circuit breaker control signal, outputs the corresponding circuit breaker opening and closing signal, controls the opening and closing of the circuit breaker, and realizes state switching; the switch signal output module includes a plurality of switch signal output interfaces, a first switch signal output interface and a tenth switch signal output interface, which are connected with the circuit breaker opening and closing loop at the corresponding position to realize the opening and closing control of the circuit breaker at different positions.

[0034] Specifically, the switch signal output module receives the logic judgment result of the logic judgment module, outputs the corresponding circuit breaker control signal, that is, outputs the corresponding circuit breaker opening and closing signal, controls the opening and closing of the circuit breaker, and realizes state switching; as shown in Figure 3 the switch signal output module includes a plurality of switch signal output interfaces, a first switch signal output interface and a tenth switch signal output interface, which are connected with the circuit breaker opening and closing loop at the corresponding position to realize the opening and closing control of the circuit breaker at different positions.

[0035] Specifically, as shown in Figure 4 the mode conversion module is used to switch the working mode of the comprehensive ground protection device according to the neutral point setting mode of the power station, and different working modes correspond to different logic judgments; optionally, the working modes include: a new energy power station without main transformer through grounding transformer small resistance grounding mode, a new energy power station with main transformer through main transformer low voltage side neutral point resistance grounding mode, and a new energy power station with main transformer through grounding transformer small resistance grounding mode.

[0036] Specifically, the new energy power station without main transformer through grounding transformer small resistance grounding mode: this design does not set the main transformer, and the system adopts Z-type grounding transformer neutral point small resistance grounding mode to realize grounding; the main transformer neutral point grounding mode is that the new energy power station has a main transformer, the low voltage side Y-type winding neutral point of the main transformer is grounded through a small resistance, and the system grounding is realized; the main transformer with grounding transformer small resistance grounding mode is that the new energy power station is provided with a main transformer, but the low voltage side of the main transformer cannot draw the neutral point, so the Z-type grounding transformer neutral point small resistance grounding is adopted to realize the system grounding.

[0037] Specifically, the man-machine interaction module is used for human control and search of the running state of the system, and the working mode switching of the mode conversion module is realized by the man-machine interaction module.

[0038] Specifically, the automatic circuit breaker device is arranged on the grounding small resistance branch and connected with the grounding resistance, and is used for realizing the switching of the grounding small resistance operation mode. The "open" and "close" signals of the automatic circuit breaker device come from the switching signal output module. When the switching signal output module outputs the "close" signal, the automatic circuit breaker device is automatically closed, and at this time, the new energy power station system is in the grounding mode. When the switching signal output module outputs the "open" signal, the automatic circuit breaker device is automatically opened, and at this time, the new energy power station system is in the non-grounding mode. Thus, the switching of the grounding small resistance operation mode is realized.

[0039] In the embodiment, a new energy power station single-phase grounding fault comprehensive protection method is provided, which is applied to a comprehensive grounding protection device, such as a new energy power station protection device as shown in the figure. Figure 5 As shown in the figure, the method comprises the following steps. Step S1: Obtain the current and voltage of each line in the power station detected by the line telemetering module.

[0040] Step S2: Switch to the corresponding mode according to the neutral point setting mode of the power station.

[0041] Step S3: Based on the amplitude and phase of the current and voltage of each line, the open and close position state of the circuit breaker in the power station, and through logical operation, it is judged whether a grounding fault occurs, and a corresponding control signal is sent according to the judgment result. The control signal is used to control the automatic circuit breaker device to close or open, so as to realize the grounding mode or non-grounding mode operation of the power station.

[0042] In some optional embodiments, the power station comprises a power collection line, a grounding line, a grounding transformer branch, a sending-out line, a bus and other lines.

[0043] Specifically, the new energy power station contains several lines, including one bus, one sending-out line and multiple branches. The sending-out line is connected with the bus, and the multiple branches are connected with the bus. The multiple branches include a power collection line branch, an SVG branch, a 35kV bus branch, a grounding transformer branch, a station transformer branch and a main transformer low-voltage side branch. The voltage transformer is arranged on the bus. The current transformer and the voltage transformer are arranged on the multiple branches respectively. The voltage transformer and the current transformer are connected with the line telemetering module respectively. The bus voltage transformer is used to detect the bus voltage. The current transformer on each branch is used to detect the current on each branch.

[0044] The grounding mode of the power station includes effective grounding and non-effective grounding. According to the national standard, the new energy power station is operated in the resistance grounding mode. In order to maintain the reliability of power supply, the distribution network can be operated in the non-grounding mode.

[0045] There are three kinds of non-effective grounding modes: neutral point small resistance grounding, neutral point high resistance grounding and neutral point resonance grounding mode. New energy station mostly adopts small resistance grounding mode, so this embodiment mainly focuses on small resistance grounding mode.

[0046] Because of different design modes of new energy power stations, the working mode of the protection system is switched to the corresponding working mode through the mode conversion module. At the same time, because of different working modes, there are different grounding protection device wiring modes, so the following will be introduced according to three different modes.

[0047] Mode one: new energy power station without step-up through grounding transformer small resistance grounding mode Figure 6 The structure diagram of the grounding protection system for the new energy power station without step-up through grounding transformer small resistance grounding mode. Figure 6 The physical parameters are as follows: (1) L1 represents 35kV0, L2 represents 35kV transmission line, L3 represents grounding transformer line, L4 and L5 represent collection line, and L6 represents other line; L7 represents grounding resistance branch; the collection line can be one or multiple, and the number is not limited in this embodiment, and the number of modules is increased according to the number of lines.

[0048] (2) PT, i.e. voltage transformer, is arranged on the L1 line, i.e. on the 35kV bus, for detecting the open delta voltage of the 35kV bus, or the 35kV bus zero sequence voltage, which can be recorded as 3U0. The signal is transmitted to the tenth analog signal interface; at the same time, the PT voltage transformer can also transmit the measured three-phase voltage on the 35kV bus, recorded as U A , U B , U C , to the seventh analog signal interface A07.

[0049] (3) T represents Z-type grounding transformer, and the neutral line is led out from the neutral point of the Z-type grounding transformer.

[0050] (4) CT represents current transformer, which is used for measuring line current; wherein CT1 represents first current transformer, CT2 represents second current transformer, CT3 represents third current transformer, CT4 represents fourth current transformer, and CT5 represents fifth current transformer; CT1 first current transformer (zero sequence current transformer) is used for collecting zero sequence current on the transmission line L2, recorded as 3I 01 , and the signal is transmitted to the first analog input signal interface A01; CT2 second current transformer (zero sequence current transformer) is used for collecting zero sequence current on the grounding transformer branch L3, recorded as 3I02 The signal is transmitted to the analog input signal second interface A02; CT3 third current transformer (zero sequence current transformer) is used to collect the zero sequence current on the collection line L4, denoted as 3I 03 The signal is transmitted to the analog input signal third interface A03; CT4 fourth current transformer (zero sequence current transformer) is used to collect the zero sequence current on the collection line L5, denoted as 3I 04 The signal is transmitted to the analog input signal fourth interface A04; CT5 fourth current transformer (zero sequence current transformer) is used to collect the zero sequence current on the other line L6, denoted as 3I 05 The signal is transmitted to the analog input signal fifth interface A05; CT6 current transformer (current transformer) is used to collect the three-phase current on the grounding transformer line L3, denoted as I A , I B , I C The signal is transmitted to the analog input signal eighth interface A08; CT current transformer (zero sequence current transformer) is used to collect the zero sequence current on the small resistance line, denoted as 3I0, and the signal is transmitted to the analog input signal ninth interface A09.

[0051] (5) R represents a small grounding resistance, which is used in a small resistance grounding system, and through the small resistance, the system realizes grounding.

[0052] (6) GL represents a disconnecting switch, which is used to connect / disconnect the grounding transformer small resistance line branch. When the disconnecting switch is in the connected position, it indicates that the line is connected, and the system operates in the small resistance grounding mode; when the disconnecting switch is in the disconnected position, it indicates that the line is disconnected, and the system operates in the non-grounding mode.

[0053] (7) T represents a grounding transformer, which is used to provide an artificial neutral point. A line is drawn from the grounding transformer neutral point, passes through the GL disconnecting switch, the DL circuit breaker, the small resistance R, and the zero sequence current transformer CT, and finally realizes system grounding.

[0054] (8) 10- represents a comprehensive grounding system protection device, which is used for grounding system protection and control. The comprehensive grounding protection device comprises: an analog signal input module, a switching signal input module, an analog-to-digital conversion module, a logic judgment module, a switching signal output module, a mode conversion module, and a human-computer interaction module. 9- indicates an automatic circuit breaker device used to open / close a grounding low-resistance line. When both automatic circuit breakers are in the closed position (i.e., both circuit breaker DL and disconnector GL are in the closed position), the grounding low-resistance line is in a conducting state, and the new energy power station operates in low-resistance grounding mode. When the automatic circuit breaker is in the open position, the grounding low-resistance line is in an open state, and the new energy power station operates in ungrounded mode. 9- indicates an automatic circuit breaker device, which includes a disconnecting switch GL and a circuit breaker DL, used to control the on / off state of the grounding transformer branch L7, thereby achieving the switching of the grounding mode. The circuit breaker type is a vacuum circuit breaker or an SF6 circuit breaker.

[0055] (9) L1 is called the 35kV bus. PT, or zero-sequence voltage transformer, is located on the L1 line and is used to detect the open delta voltage of the 35kV bus, or the zero-sequence voltage of the 35kV bus, which can be denoted as 3U0.

[0056] L2 is called the transmission line, and CT1, the first current transformer, is the zero-sequence current transformer on the 35kV transmission line. This zero-sequence current transformer can detect the zero-sequence current on the transmission line L2, and can be denoted as 3I01.

[0057] L3 is called the grounding transformer branch, which includes the grounding transformer (T) and the small resistance branch on the grounding transformer branch. The high-voltage side of the grounding transformer T is connected to the busbar, and the neutral point of the grounding transformer T is grounded in sequence through the disconnecting switch GL, the circuit breaker DL, and the resistor R. The connection group of this grounding transformer is ZN connection or ZNyn connection, where Z indicates that the primary winding is Z-type connection, y indicates that the secondary winding is star connection, and N and n indicate the neutral line is led out.

[0058] In this scenario, the fault types involved are categorized as follows: grounding faults in collector lines L4 and L5, and other lines L6; grounding faults in 35kV busbar L1; and grounding / phase-to-phase faults in grounding transformer line L3.

[0059] (1) For a ground fault occurring in collector line L4, the following judgment and protection methods are available: At time t1, 3U0≥U set 3I0≥I set、 3I 02 ≥I set 3I 03 ≥I set The integrated grounding protection device 10 disconnects the DL circuit breaker, and the system switches from operating in the low-resistance grounding mode to operating in the ungrounded mode. After time t1 to t2, the integrated grounding protection device 10 checks again whether the criterion is met: 3U0≥U set : (a) If 3U0≥Uset : that is 3U0 < U set : that is to show that the instantaneous single-phase ground fault occurs in the collector line L4, and after the fault occurs, the collector line L4 automatically extinguishes the arc, and the insulation is automatically restored, at this time the integrated ground protection device 10 will control the DL circuit breaker to automatically close, and the system grounding mode is converted from the ungrounded operation to the small resistance grounding mode operation, and the system returns to normal. This judgment mode can greatly improve the stability of system power supply.

[0060] (b) if 3U0≥U set : that is to show that the collector line L4 is a permanent ground fault, and the integrated ground protection device 10 does not execute the automatic closing instruction; at the same time, the integrated ground protection device 10 realizes accurate line selection according to the aforementioned criterion: 3I0≥I set , 3I 02 ≥I set , 3I 03 ≥I set , t2 time integrated ground protection device 10 will disconnect the corresponding circuit breaker DL3, disconnect the corresponding collector line L4 of the ground fault, and exclude the ground fault line. After the fault is removed, 3U0 < U set , t3 time integrated ground protection device 10 will control the DL circuit breaker to automatically close.

[0061] When the above-mentioned collector line L4 ground fault is a permanent ground fault, the corresponding DL circuit breaker and DL3 circuit breaker are disconnected, and the system is converted to ungrounded operation, at this time the original single-phase ground protection system has completely failed, but the integrated ground protection device 10 can still work normally.

[0062] When the DL circuit breaker and the DL3 circuit breaker are disconnected (on the basis of the ground fault of the collector line L4), the system again occurs a single-phase ground fault, the criterion for judging line selection will use the amplitude and phase comparison method for line selection, so as to remove the ground fault. For example: When the collector line L5 occurs a single-phase ground fault, the amplitude and phase comparison criterion is: 3U0≥U set , 3I 04 ≥I set , -180°≤arg(3I 04 / 3U0)≤0°, when the above criterion is satisfied, the integrated ground protection device 10 controls the DL4 circuit breaker to open, and the collector line L5 is removed.

[0063] When other lines L6 occur a single-phase ground fault, the amplitude and phase comparison criterion is: 3U0≥U set , 3I 05 ≥I set , -180°≤arg(3I 053U0)≤0°, when the above criterion is satisfied, the integrated grounding protection device 10 controls the DL5 circuit breaker to open, and the other lines L6 are cut off.

[0064] When a single-phase grounding fault occurs in the 35kV bus L1, the amplitude and phase criterion is: 3U0>U set , 3I 01 >I set , 3I 02 >I set , 3I 04 >I set , 3I 05 >I set , -180°≤arg(3I 01 / 3U0)≤0°, -180°≤arg(3I 02 / 3U0)≤0°, -180°≤arg(3I0 / 3U0)≤0°, -180°≤arg(3I 05 / 3U0)≤0°, when the above criterion is satisfied, the integrated grounding protection device 10 controls the DL1 circuit breaker, the DL2 circuit breaker, the DL4 circuit breaker, and the DL5 circuit breaker to open, and all lines are cut off.

[0065] (2) For the grounding fault of the collection line L5, the following judgment and protection method is used: At t1, 3U0>U set , 3I0>I set , 3I 02 >I se , 3I 04 >I set , the integrated grounding protection device 10 disconnects the DL circuit breaker, and the system is converted from the small-resistance grounding mode to the ungrounded mode; After t1-t2, the integrated grounding protection device 10 detects again whether the criterion 3U0>U set is satisfied: (a) If 3U0<U set , that is, 3U0<U set , it is indicated that the collection line L5 has a transient single-phase grounding fault, and the arc of the collection line L5 is automatically extinguished and the insulation is automatically restored after the fault occurs. At this time, the integrated grounding protection device 10 controls the DL circuit breaker to automatically close, the grounding mode of the system is converted from the ungrounded mode to the small-resistance grounding mode, and the system is restored to normal. This judgment mode can greatly improve the stability of system power supply.

[0066] (b) If 3U0>U setThis indicates that a permanent grounding fault has occurred in the collector line L5, and the integrated grounding protection device 10 will not execute the automatic closing command; at the same time, the integrated grounding protection device 10, according to the aforementioned criterion: 3I0≥I set 3I 02 ≥I se 3I 04 ≥I set This achieves precise line selection. At time t2, the integrated grounding protection device 10 disconnects the corresponding circuit breaker DL4, disconnects the corresponding collector line L5, and eliminates the grounding fault line. After the fault is cleared, 3U0... set At time t3, the integrated grounding protection device 10 will control the DL circuit breaker to automatically close.

[0067] When the ground fault of the above-mentioned collector line L5 is a permanent ground fault, the corresponding DL circuit breaker and DL4 circuit breaker will both be disconnected, and the system will switch to ungrounded operation. At this time, the original single-phase ground fault protection system has completely failed, but the integrated ground fault protection device 10 can still work normally.

[0068] When the DL circuit breaker and DL4 circuit breaker are disconnected (based on a ground fault occurring in collector line L5), and a single-phase ground fault occurs again in the system, the criterion used for line selection will be amplitude and phase comparison, thereby ensuring the ground fault is cleared. For example: When a single-phase ground fault occurs in collector line L4, the amplitude-phase comparison criterion is: 3U0 ≥ U set 3I 03 ≥I set -180°≤arg(3I) 03 When the above criteria are met, the integrated grounding protection device 10 controls the DL3 circuit breaker to open and disconnect the collector line L4.

[0069] When a single-phase ground fault occurs on other line L6, the amplitude-phase comparison criterion is: 3U0 ≥ U set 3I 05 ≥I set -180°≤arg(3I) 05 When the above criteria are met, the integrated grounding protection device 10 controls the DL5 circuit breaker to trip and disconnect other lines L6.

[0070] When a single-phase ground fault occurs on 35kV bus L1, the amplitude-phase ratio criterion is: 3U0≥U set 3I 01 ≥I set 3I 02 ≥I set 3I 03 ≥I set 3I​05 ≥I set -180 o ≤arg(3I 01 ) / (3U0)≤0 o -180°≤arg(3I) 02 ) / (3U0)≤0°、-180°≤arg(3I 03 ) / (3U0)≤0°、-180°≤arg(3I 05 When the above criteria are met, the integrated grounding protection device 10 controls the DL1 circuit breaker, DL2 circuit breaker, DL3 circuit breaker, and DL5 circuit breaker to open and disconnect all lines.

[0071] (3) For ground faults occurring on other lines L6, the following judgment and protection methods apply: At time t1, 3U0≥U set 3I0≥I set 3I 02 ≥I set 3I 05 ≥I set The integrated grounding protection device 10 disconnects the DL circuit breaker, and the system switches from operating in the low-resistance grounding mode to operating in the ungrounded mode. After time t1 to t2, the integrated grounding protection device 10 checks again whether the criterion is met: 3U0≥U set : (a) If 3U0≥U set : i.e. 3U0 set This indicates that the fault occurring on other line L6 is a transient single-phase ground fault. After the fault occurs, the arc on other line L6 is automatically extinguished and the insulation is automatically restored. At this time, the integrated grounding protection device 10 will control the DL circuit breaker to automatically close, and the system grounding mode will switch from ungrounded operation to low-resistance grounding operation, and the system will return to normal. This judgment mode will greatly improve the stability of the system power supply.

[0072] (b) If 3U0≥U set This indicates that a permanent grounding fault has occurred on other line L6, and the integrated grounding protection device 10 will not execute the automatic closing command; at the same time, the integrated grounding protection device 10, based on the aforementioned criterion: 3I0≥I set 3I 02 ≥I set 3I 05 ≥I sett This achieves precise line selection. At time t2, the integrated grounding protection device 10 disconnects the corresponding circuit breaker DL5, disconnects the other line L6 corresponding to the grounding fault, and eliminates the grounding fault line. After the fault is cleared, 3U0... set ​​The integrated grounding protection device 10 will control the DL circuit breaker to automatically close at the t3 moment.

[0073] When the grounding fault of the other line L6 is a permanent grounding fault, the corresponding DL circuit breaker and DL5 circuit breaker are both opened, and the system is converted to operate in an ungrounded mode. At this time, the original single-phase grounding protection system has completely failed, but the integrated grounding protection device 10 can still work normally.

[0074] When the system again occurs a single-phase grounding fault after the DL circuit breaker and the DL5 circuit breaker are opened (on the basis of the grounding fault of the other line L6), the criterion for judging line selection will adopt the amplitude-phase comparison type to select the line, so as to cut off the grounding fault: for example, When the collector line L4 occurs a single-phase grounding fault, the amplitude-phase comparison criterion is: 3U0≥U set , 3I 03 ≥I set , -180°≤arg(3I 03 ) / (3U0)≤0°. When the above criterion is met, the integrated grounding protection device 10 controls the DL3 circuit breaker to open, and cuts off the collector line L4.

[0075] When the collector line L5 occurs a single-phase grounding fault, the amplitude-phase comparison criterion is: 3U0≥U set , 3I 04 ≥I set , -180°≤arg(3I 04 ) / (3U0)≤0°. When the above criterion is met, the integrated grounding protection device 10 controls the DL4 circuit breaker to open, and cuts off the collector line L5.

[0076] When the 35kV bus L1 occurs a single-phase grounding fault, the amplitude-phase comparison criterion is: 3U0≥U set , 3I 01 ≥I set , 3I 02 ≥I set , 3I 03 ≥I set , 3I 04 ≥I set , -180°≤arg(3I 01 ) / (3U0)≤0°, -180°≤arg(3I 02 ) / (3U0)≤0°, -180°≤arg(3I 03 ) / (3U0)≤0°, -180°≤arg(3I 04-180° < arg(3I0) / (3U0) < 0°, when the above criteria are satisfied, the integrated grounding protection device 10 controls DL1 circuit breaker, DL2 circuit breaker, DL3 circuit breaker, DL4 circuit breaker to open, and removes all lines.

[0077] (4) whether the type of fault occurs is determined according to the 35kV bus L1 single-phase grounding fault determination condition. The 35kV bus L1 single-phase grounding fault determination condition is: t1, 3U0≥U set , 3I0≥I set , 3I 01 ≥I set , 3I 02 ≥I set , 3I 03 ≥I set , 3I 04 ≥I set , 3I 05 ≥I set , -180°≤arg(3I 01 ) / (3U0)≤0°, -180°≤arg(3I 02 ) / (3U0)≤0°, -180°≤arg(3I 03 ) / (3U0)≤0°, -180°≤arg(3I 04 ) / (3U0)≤0°, -180°≤arg(3I 05 ) / (3U0)≤0°, since the bus fault is mostly permanent fault, the DL automatic closing instruction is not executed; meanwhile, the integrated grounding protection device 10 can be used as a backup protection of bus protection, and at t2, the DL1 circuit breaker, DL2 circuit breaker, DL3 circuit breaker, DL4 circuit breaker and DL5 circuit breaker are opened.

[0078] (5) whether the type of fault occurs is determined according to the grounding transformer line L3 grounding fault determination condition. The grounding transformer line L3 grounding fault determination condition is: t1, 3U0≥U set , 3I0≥I set , since the grounding transformer line fault is mostly permanent fault, the integrated grounding protection device 10 does not execute the DL automatic closing instruction; at t2, the integrated grounding protection device 10 executes the DL2 opening instruction.

[0079] The grounding transformer line L3 occurs phase-to-phase fault: in the embodiment, the integrated grounding protection device 10 can determine whether the type of fault occurs according to the grounding transformer line L3 phase-to-phase fault determination condition. The grounding transformer line L3 phase-to-phase fault determination condition is: t1, phase current I A-I0≥I set or I B -I0≥I set or I C -I0≥I set (3I0=I A +I B +I C , t2 time, the integrated grounding protection device 10 executes DL2 tripping instruction.

[0080] Mode two: new energy power station through the main transformer step-up mode through the main transformer low voltage side neutral point grounding mode Figure 7 For new energy power station through the main transformer step-up mode through the main transformer low voltage side neutral point grounding mode-grounding system structure diagram. Figure 7 The physical parameter meanings are as follows: (1) L1 represents 35kV bus, L2 represents the transmission line after the main transformer step-up, L3 and L4 represent the collection line, and L5 represents other lines; L6 represents the grounding resistor branch; the collection line can be one or multiple, and the number of the collection line is not specifically limited in the embodiment, and the number of the module is increased according to the number of the line.

[0081] (2) PT, i.e. voltage transformer, is arranged on the L1 line, i.e. 35kV bus, for detecting the open delta voltage of the 35kV bus, or the 35kV bus zero sequence voltage, which can be recorded as 3U0. The signal is transmitted to the tenth analog signal interface A10; at the same time, the PT voltage transformer can also measure the three-phase voltage on the 35kV bus, recorded as U A , U B , U C , and transmit the signal to the eighth analog signal interface A08.

[0082] (3) CT represents a current transformer for measuring line current; wherein CT1 represents a first current transformer, CT2 represents a second current transformer, CT3 represents a third current transformer, and CT4 represents a fourth current transformer; CT1, the first current transformer (zero sequence current transformer), is used for collecting the zero sequence current on the transmission line L2, recorded as 3I 01 , and the signal is transmitted to the first analog input signal interface A01; CT2, the second current transformer (zero sequence current transformer), is used for collecting the zero sequence current on the collection line L3, recorded as 3I 02 , and the signal is transmitted to the second analog input signal interface A02; CT3, the third current transformer (zero sequence current transformer), is used for collecting the zero sequence current on the collection line L4, recorded as 3I03 The signal is transmitted to the analog input signal third interface A03; CT4 fourth current transformer (zero sequence current transformer) is used to collect the zero sequence current on the other line L5, denoted as 3I 04 The signal is transmitted to the analog input signal fourth interface A04; CT current transformer (zero sequence current transformer) is used to collect the zero sequence current on the small resistance line L6, denoted as 3I0, and the signal is transmitted to the analog input signal ninth interface A09.

[0083] (4) DL represents a circuit breaker, which is used to connect / disconnect the line. When the circuit breaker is in the connected position, the line is connected; when the circuit breaker is in the disconnected position, the line is disconnected. The on-off state of the line is controlled by controlling the on-off state of the circuit breaker. Wherein DL represents the circuit breaker; DL1 represents the first circuit breaker, DL2 represents the second circuit breaker, DL3 represents the third circuit breaker, and DL4 represents the fourth circuit breaker; The DL1 first circuit breaker switch quantity signal is transmitted to the switch quantity signal input first interface B01; The DL2 second circuit breaker switch quantity signal is transmitted to the switch quantity signal input second interface B02; The DL3 third circuit breaker switch quantity signal is transmitted to the switch quantity signal input third interface B03; The DL4 fourth circuit breaker switch quantity signal is transmitted to the switch quantity signal input fourth interface B04; The DL circuit breaker switch quantity signal is transmitted to the switch quantity signal input tenth interface B10; The DL1 first circuit breaker on-off control loop is transmitted to the switch quantity signal output first interface C01; The DL2 second circuit breaker on-off control loop is transmitted to the switch quantity signal output second interface C02; The DL3 third circuit breaker on-off control loop is transmitted to the switch quantity signal output third interface C03; The DL4 fourth circuit breaker on-off control loop is transmitted to the switch quantity signal output fourth interface C04; The DL circuit breaker on-off control loop is transmitted to the switch quantity signal output ninth interface C09; The DL circuit breaker on-off control loop is transmitted to the switch quantity signal output tenth interface C10.

[0084] (5) R represents a grounding small resistance, which is used in a small resistance grounding system. Through the small resistance, the system realizes grounding.

[0085] (6) GL represents a disconnector, which is used to connect / disconnect the grounding transformer small resistance line branch. When the disconnector is in the connected position, it indicates that the line is connected, and the system is in small resistance grounding mode. When the disconnector is in the disconnected position, it indicates that the line is disconnected, and the system is in ungrounded mode.

[0086] (7) ZB represents the main transformer, which boosts the 35kV voltage to 110kV or 220kV, and the low-voltage side is Y-connected to provide a neutral point, from which the line is drawn through the GL disconnector, DL circuit breaker, small resistance R, and zero sequence current transformer CT, ultimately realizing system grounding.

[0087] (8) 10- represents a comprehensive grounding system protection device for grounding system protection and control. The comprehensive grounding protection device includes: analog signal input module, switch signal input module, analog-to-digital conversion module, logic judgment module, switch signal output module, mode conversion module, and human-computer interaction module. 9- represents an automatic circuit breaker device for connecting / disconnecting the grounding small resistance line. When the automatic circuit breaker device is in the connected position (i.e., the circuit breaker DL and the disconnector GL are both in the connected position), the grounding small resistance line is in the connected state, and the new energy power station is in small resistance grounding mode. When the automatic circuit breaker device is in the disconnected position, the grounding small resistance line is in the disconnected state, and the new energy power station is in ungrounded mode. 9- represents an automatic circuit breaker device, which includes a disconnector GL and a circuit breaker DL, used to control the on / off of the grounding transformer branch L6, thereby realizing the switching of grounding mode. The circuit breaker is a vacuum circuit breaker or an SF6 circuit breaker.

[0088] In mode two, the types of grounding faults involved are: grounding faults of the collector line L3, L4, and other lines L5; grounding faults of the 35kV bus L1; and grounding faults of the low-voltage side of the main transformer and the lead line.

[0089] (1) For a grounding fault of the collector line L3, the following judgment and protection methods are used: At time t1, 3U0≥U set , 3I0≥I set , 3I 01 ≥I set , 3I 02 ≥I set , and the comprehensive grounding protection device 10 disconnects the DL circuit breaker, switching the system from small resistance grounding mode to ungrounded mode. After time t1-t2, the comprehensive grounding protection device 10 detects again whether the criterion 3U0≥U set is met: (a) If 3U0≥U set: i.e. 3U0 set This indicates that a transient single-phase ground fault occurred in collector line L3. After the fault occurred, collector line L3 automatically extinguished the arc and the insulation automatically recovered. At this time, the integrated grounding protection device 10 will control the DL circuit breaker to automatically close, and the system grounding mode will switch from ungrounded operation to low-resistance grounding operation, and the system will return to normal. This judgment mode will greatly improve the stability of the system power supply.

[0090] (b) If 3U0≥U set This indicates that a permanent grounding fault has occurred in collector line L3, and the integrated grounding protection device 10 will not execute the automatic closing command; at the same time, the integrated grounding protection device 10, according to the aforementioned criterion: 3I0≥I set 3I 01 ≥I set 3I 02 ≥I set This achieves precise line selection. At time t2, the integrated grounding protection device 10 disconnects the corresponding circuit breaker DL2, disconnects the corresponding collector line L3 of the grounding fault, and eliminates the grounding fault line. After the fault is cleared, 3U0... set At time t3, the integrated grounding protection device 10 will control the DL circuit breaker to automatically close.

[0091] When the L3 grounding fault of the above-mentioned collector line is a permanent grounding fault, the corresponding DL circuit breaker and DL2 circuit breaker will both be disconnected, and the system will switch to ungrounded operation. At this time, the original single-phase grounding protection system has completely failed, but the integrated grounding protection device 10 can still work normally.

[0092] When circuit breakers DL and DL2 are disconnected (based on a ground fault in collector line L3), and a single-phase ground fault occurs again in the system, the criterion for fault selection will be amplitude and phase comparison, thereby ensuring the ground fault is cleared. For example: When a single-phase ground fault occurs in collector line L4, the amplitude-phase comparison criterion is: 3U0 ≥ U set 3I 03 ≥I set -180°≤arg(3I) 03 When the above criteria are met, the integrated grounding protection device 10 controls the DL3 circuit breaker to open and disconnect the collector line L4.

[0093] When a single-phase ground fault occurs on other line L5, the amplitude-phase comparison criterion is: 3U0 ≥ U set 3I 04 ≥I set -180°≤arg(3I) 04 ​​When the above criteria are met, the integrated grounding protection device 10 controls the DL4 circuit breaker to trip and disconnect other lines L5.

[0094] When a single-phase ground fault occurs on 35kV bus L1, the amplitude-phase ratio criterion is: 3U0≥U set 3I 01 ≥I set 3I 03 ≥I set 3I 04 ≥I set -180°≤arg(3I) 01 ) / (3U0)≤0°、-180°≤arg(3I 03 ) / (3U0)≤0°、-180°≤arg(3I 04 When the above criteria are met, the integrated grounding protection device 10 controls the DL1 circuit breaker, DL3 circuit breaker, and DL4 circuit breaker to open and disconnect all lines.

[0095] (2) For a ground fault occurring in collector line L4, the following judgment and protection methods are available: At time t1, 3U0≥U set 3I0≥I set、 3I 01 ≥I set 3I 03 ≥I set At this time, the zero-sequence voltage exceeds the limit, and the integrated grounding protection device 10 disconnects the DL circuit breaker, and the system switches from operating in the small resistance grounding mode to operating in the ungrounded mode; After time t1 to t2, the integrated grounding protection device 10 checks again whether the criterion is met: 3U0≥U set : (a) If 3U0≥U set : i.e. 3U0 set This indicates that a transient single-phase ground fault occurred in collector line L4. After the fault occurred, collector line L4 automatically extinguished the arc and the insulation automatically recovered. At this time, the integrated grounding protection device 10 will control the DL circuit breaker to automatically close, and the system grounding mode will switch from ungrounded operation to low-resistance grounding operation, and the system will return to normal. This judgment mode will greatly improve the stability of the system power supply.

[0096] (b) If 3U0≥U set This indicates that a permanent ground fault has occurred in collector line L4, and the integrated grounding protection device 10 will not execute the automatic closing command; at the same time, the integrated grounding protection device 10, according to the aforementioned criterion: 3I0≥I set 3I 01 ≥I​set , 3I 03 ≥ I set , realize accurate line selection. At t2 moment, the integrated grounding protection device 10 will disconnect the corresponding circuit breaker DL3, disconnect the grounding fault corresponding collector line L4, and exclude the grounding fault line. After the fault is removed, 3U0 set , at t3 moment, the integrated grounding protection device 10 will control the DL circuit breaker to automatically close.

[0097] When the above-mentioned collector line L4 grounding fault is a permanent grounding fault, the corresponding DL circuit breaker and DL3 circuit breaker are both disconnected, and the system is converted to operate in an ungrounded manner. At this time, the original single-phase grounding protection system has completely failed, but the integrated grounding protection device 10 can still work normally.

[0098] When the DL circuit breaker and the DL3 circuit breaker are disconnected (on the basis of the grounding fault of the collector line L4), if a single-phase grounding fault occurs again, the criterion for judging the line selection will use the amplitude and phase comparison method to select the line, so as to remove the grounding fault. For example: When the collector line L3 occurs a single-phase grounding fault, the amplitude and phase comparison criterion is: 3U0 set , 3I 02 ≥ I set , -180°≤arg(3I 02 ) / (3U0)≤0°. When the above-mentioned criterion is met, the integrated grounding protection device 10 controls the DL2 circuit breaker to open, and removes the collector line L3.

[0099] When the other line L5 occurs a single-phase grounding fault, the amplitude and phase comparison criterion is: 3U0 set , 3I 04 ≥ I set , -180°≤arg(3I 04 ) / (3U0)≤0°. When the above-mentioned criterion is met, the integrated grounding protection device 10 controls the DL4 circuit breaker to open, and removes the other line L5.

[0100] When the 35kV bus L1 occurs a single-phase grounding fault, the amplitude and phase comparison criterion is: 3U0 set , 3I 01 ≥ I set , 3I 02 ≥ I set , 3I 04 ≥ I set , -180°≤arg(3I 01 ) / (3U0)≤0°, -180°≤arg(3I 02 ) / (3U0)≤0°, -180°≤arg(3I 04) / (3U0)≤0°, when the above criterion is met, the integrated grounding protection device 10 controls the DL1 circuit breaker, the DL2 circuit breaker and the DL4 circuit breaker to be tripped, and all lines are cut off.

[0101] (3) When the other line L5 has a grounding fault, the following judgment and protection method is used: At t1, 3U0≥U set , 3I0≥I set , 3I 01 ≥I set , 3I 04 ≥I set , at this time, the zero sequence voltage exceeds the limit, the integrated grounding protection device 10 disconnects the DL circuit breaker, and the system is converted from the small resistance grounding mode to the ungrounded mode; After t1-t2, the integrated grounding protection device 10 detects again whether the criterion 3U0≥U set is met. (a) If 3U0<U set , that is, 3U0<U set , it indicates that the other line L5 has a transient single-phase grounding fault, and the arc of the other line L5 is automatically extinguished and the insulation is automatically restored, at this time, the integrated grounding protection device 10 controls the DL circuit breaker to be automatically closed, the system is converted from the ungrounded mode to the small resistance grounding mode, and the system is restored to normal. This judgment mode can greatly improve the stability of system power supply.

[0102] (b) If 3U0≥U set , it indicates that the other line L5 has a permanent grounding fault, the integrated grounding protection device 10 does not execute the automatic closing instruction; meanwhile, the integrated grounding protection device 10 realizes accurate line selection according to the aforementioned criterion 3I0≥I set , 3I 01 ≥I set , 3I 04 ≥I sett . At t2, the integrated grounding protection device 10 disconnects the corresponding circuit breaker DL4 and disconnects the other line L5 corresponding to the grounding fault, and the grounding fault line is excluded. After the fault is cut off, 3U0<U set , at t3, the integrated grounding protection device 10 controls the DL circuit breaker to be automatically closed.

[0103] When the above other line L5 grounding fault is a permanent grounding fault, the corresponding DL circuit breaker and DL4 circuit breaker are disconnected, and the system is converted to the ungrounded mode, at this time, the original single-phase grounding protection system has completely failed, but the integrated grounding protection device 10 can still work normally.

[0104] When the single-phase ground fault occurs again after the DL circuit breaker and the DL4 circuit breaker are disconnected (on the basis that the other line L5 has a ground fault), the criterion for judging the line selection will adopt the amplitude-phase comparison type to select the line, so as to cut off the ground fault. For example: When the single-phase ground fault occurs in the collector line L3, the amplitude-phase comparison criterion is: 3U0≥U set , 3I 02 ≥I set , -180°≤arg(3I 02 ) / (3U0)≤0°. When the above criterion is met, the integrated ground protection device 10 controls the DL2 circuit breaker to trip, and cuts off the collector line L3.

[0105] When the single-phase ground fault occurs in the collector line L4, the amplitude-phase comparison criterion is: 3U0≥U set , 3I 03 ≥I set , -180°≤arg(3I 03 ) / (3U0)≤0°. When the above criterion is met, the integrated ground protection device 10 controls the DL3 circuit breaker to trip, and cuts off the collector line L4.

[0106] When the single-phase ground fault occurs in the 35kV bus L1, the amplitude-phase comparison criterion is: 3U0≥U set , 3I 02 ≥I set , 3I 03 >I set , -180°≤arg(3I 01 ) / (3U0)≤0°, -180°≤arg(3I 02 ) / (3U0)≤0°, -180°≤arg(3I 03 ) / (3U0)≤0°. When the above criterion is met, the integrated ground protection device 10 controls the DL1 circuit breaker, the DL2 circuit breaker, and the DL3 circuit breaker to trip, and cuts off all lines.

[0107] (4) When the ground fault occurs in the other line L5, the following judgment and protection method is adopted: The integrated ground protection device 10 can determine whether the type of fault occurs according to the 35kV bus L1 single-phase ground fault determination condition. The 35kV bus L1 single-phase ground fault determination condition is: At t1, 3U0≥U set , 3I0≥I set , 3I 01 ≥I set , 3I 02 ≥I set , 3I 03 ≥Iset , 3I 04 ≥ I set , -180°≤arg(3I 01 ) / (3U0)≤0°, -180°≤arg(3I 02 ) / (3U0)≤0°, -180°≤arg(3I 03 ) / (3U0)≤0°, -180°≤arg(3I 04 ) / (3U0)≤0°, since bus fault is mostly permanent fault, the integrated grounding protection device 10 does not execute the DL automatic closing instruction; meanwhile, the integrated grounding protection device 10 can be used as a bus protection backup protection, and the DL1 breaker, the DL2 breaker, the DL3 breaker and the DL4 breaker are disconnected at the t2 moment.

[0108] (5) Single-phase grounding fault occurs at the low-voltage side of the main transformer, and the main transformer differential protection acts to remove the fault.

[0109] Mode three: new energy power station through main transformer step-up and small resistance grounding mode through grounding transformer Figure 8 The integrated grounding protection device 10 is a new energy power station through main transformer step-up and small resistance grounding mode grounding system protection schematic diagram. Figure 8 The physical parameter meanings in the integrated grounding protection device 10 are as follows: (1) L1 represents a 35kV bus, L2 represents a sending-out line through main transformer step-up, L3 represents a grounding transformer line, L4 represents a power collection line, L5 represents a power collection line, and L6 represents a grounding small resistance branch; the power collection line can be one or multiple, and the number of the power collection line is not limited in the embodiment, and the number of the module is increased according to the number of the line.

[0110] (2) PT, i.e. voltage transformer, is arranged on the L1 line, i.e. on the 35kV bus, and is used for detecting the open delta voltage of the 35kV bus, or the zero sequence voltage of the 35kV bus, which can be recorded as 3U0. The signal is transmitted to the tenth analog signal interface A10; at the same time, the PT voltage transformer can also measure the three-phase voltage on the 35kV bus, which is recorded as U A , U B , U C , and the signal is transmitted to the eighth analog signal interface A08.

[0111] (3) T represents a Z-type grounding transformer, and a neutral line is led out from the neutral point of the Z-type grounding transformer.

[0112] (4) CT represents a current transformer, which is used for measuring line current; wherein CT1 represents a first current transformer, CT2 represents a second current transformer, CT3 represents a third current transformer, and CT4 represents a fourth current transformer; CT1 first current transformer (zero sequence current transformer) is used to collect zero sequence current on sending-out line L2, denoted as 3I 01 The signal is transmitted to analog input signal first interface A01. CT2 second current transformer (zero sequence current transformer) is used to collect zero sequence current on grounding transformer line L3, denoted as 3I 02 The signal is transmitted to analog input signal second interface A02. CT3 third current transformer (zero sequence current transformer) is used to collect zero sequence current on collecting line L4, denoted as 3I 03 The signal is transmitted to analog input signal third interface A03. CT4 fourth current transformer (zero sequence current transformer) is used to collect zero sequence current on collecting line L5, denoted as 3I 04 The signal is transmitted to analog input signal fourth interface A04. CT5 current transformer (current transformer) is used to collect three-phase current on grounding transformer line L3, denoted as I A , I B , I C The signal is transmitted to analog input signal fifth interface A05. CT current transformer (zero sequence current transformer) is used to collect zero sequence current on small resistance line L6, denoted as 3I0, the signal is transmitted to analog input signal ninth interface A09.

[0113] (5) DL represents a circuit breaker, used to connect / disconnect the line, when the circuit breaker is in the connected position, the line is connected; when the circuit breaker is in the disconnected position, the line is disconnected, the on-off of the line is controlled by controlling the on-off state of the circuit breaker; wherein DL represents the circuit breaker; DL1 represents the first circuit breaker, DL2 represents the second circuit breaker, DL3 represents the third circuit breaker, and DL4 represents the fourth circuit breaker. DL1 first circuit breaker switch quantity signal is transmitted to switch quantity signal input first interface B01. DL2 second circuit breaker switch quantity signal is transmitted to switch quantity signal input second interface B02. DL3 third circuit breaker switch quantity signal is transmitted to switch quantity signal input third interface B03. DL4 fourth circuit breaker switch quantity signal is transmitted to switch quantity signal input fourth interface B04. DL circuit breaker switch quantity signal is transmitted to switch quantity signal input tenth interface B10. DL1 first circuit breaker on-off control loop is transmitted to switch quantity signal output first interface C01. DL2 second circuit breaker on-off control loop is transmitted to switch quantity signal output second interface C02. DL3 third circuit breaker switching control loop transmits to switch signal output third interface C03; DL4 fourth circuit breaker switching control loop transmits to switch signal output fourth interface C04; DL circuit breaker opening control loop transmits to switch signal output ninth interface C09; DL circuit breaker closing control loop transmits to switch signal output tenth interface C10.

[0114] (6) R represents a small grounding resistance, used in a small resistance grounding system, through which the system realizes grounding.

[0115] (7) GL represents a disconnector, used to switch on / off the small resistance line branch of the grounding transformer, when the disconnector is in the on position, it indicates that the line is connected and the system is in small resistance grounding mode; when the disconnector is in the off position, it indicates that the line is disconnected and the system is in non-grounding mode.

[0116] (8) ZB represents a main transformer, which boosts the voltage from 35kV to 110kV or 220kV, and the high-voltage side is Y-connected and the low-voltage side is delta-connected.

[0117] (9) JDB represents a grounding transformer, the high-voltage side of which is Z-connected, and a neutral line is drawn from the neutral point of the high-voltage side to provide an artificial neutral point, which is grounded through the GL disconnector, DL circuit breaker, R small resistance, and CT zero-sequence current transformer.

[0118] (10) 10- represents a comprehensive grounding system protection device, used for grounding system protection and control; the comprehensive grounding protection device comprises: an analog signal input module, a switch signal input module, an analog-to-digital conversion module, a logic judgment module, a switch signal output module, a mode conversion module, and a human-computer interaction module. 9- represents an automatic circuit breaker device, used to switch on / off the small resistance line, when both the automatic circuit breaker device and the disconnector GL are in the on position, the small resistance line is in the connected state, and the new energy power station is in small resistance grounding mode; when the automatic circuit breaker device is in the off position, the small resistance line is in the disconnected state, and the new energy power station is in non-grounding mode. 9- represents an automatic circuit breaker device, which comprises a disconnector GL and a circuit breaker DL, used to control the on / off of the grounding branch L6, thereby realizing the switching of the grounding mode. The circuit breaker is a vacuum circuit breaker or an SF6 circuit breaker.

[0119] In mode three, the types of ground fault involved are: ground fault of the collector line L4, L5; ground fault of the 35kV bus L1; ground and phase-to-phase fault of the grounding transformer line L3.

[0120] (1) Ground fault of the collector line L4, the following judgment and protection method is used: At time t1, 3U0≥U set , 3I0≥I set , 3I 02 ≥I set , 3I 03 ≥I set , and the zero sequence voltage exceeds the limit, the comprehensive ground protection device 10 disconnects the DL circuit breaker, and the system is converted from small resistance grounding mode to ungrounded mode; After time t1-t2, the comprehensive ground protection device 10 detects again whether the criterion 3U0≥U set is met: (a) If 3U0≥U set is not met: i.e. 3U0<U set , it indicates that the collector line L4 has a transient single-phase ground fault, and the arc of the collector line L4 is extinguished automatically after the fault occurs, and the insulation is automatically restored. At this time, the comprehensive ground protection device 10 controls the DL circuit breaker to be automatically closed, and the system is converted from ungrounded operation to small resistance grounding operation, and the system returns to normal. This judgment mode can greatly improve the stability of system power supply.

[0121] (b) If 3U0≥U set is met: it indicates that the collector line L4 has a permanent ground fault, and the comprehensive ground protection device 10 does not execute the automatic closing instruction; at the same time, the comprehensive ground protection device 10 realizes accurate line selection according to the aforementioned criterion: 3I0≥I set , 3I 02 ≥I set , 3I 03 ≥I set . At time t2, the comprehensive ground protection device 10 disconnects the corresponding circuit breaker DL3 and disconnects the corresponding collector line L4 of the ground fault, and excludes the ground fault line. After the fault is removed, 3U0<U set， At time t3, the comprehensive ground protection device 10 controls the DL circuit breaker to be automatically closed.

[0122] When the above-mentioned ground fault of the collector line L4 is a permanent ground fault, the corresponding DL circuit breaker and DL3 circuit breaker are disconnected, and the system is converted to ungrounded operation. At this time, the original single-phase ground protection system has completely failed, but the comprehensive ground protection device 10 can still work normally.

[0123] When circuit breakers DL and DL3 are disconnected (based on a ground fault in collector line L4), and a single-phase ground fault occurs again in the system, the criterion for fault selection will be amplitude and phase comparison, thus ensuring the ground fault is cleared. For example: When a single-phase ground fault occurs in collector line L5, the amplitude-phase comparison criterion is: 3U0 ≥ U set 3I 04 ≥I set -180°≤arg(3I) 04 / (3U0)≤0°, when the above criteria are met, the integrated grounding protection device 10 controls the DL4 circuit breaker to open and disconnect the collector line L5.

[0124] When a single-phase ground fault occurs in grounding transformer line L3, the amplitude-phase comparison criterion is: 3U0 ≥ U set 3I 02 ≥I set -180°≤arg(3I) 02 / (3U0)≤0°, when the above criteria are met, the integrated grounding protection device 10 controls the DL2 circuit breaker to open and disconnect the grounding transformer line L3.

[0125] When a single-phase ground fault occurs on 35kV bus L1, the amplitude-phase ratio criterion is: 3U0≥U set 3I 01 ≥I set 3I 02 ≥I set 3I 04 ≥I set -180 o ≤arg(3I 01 ) / (3U0)≤0 o -180°≤arg(3I) 02 / (3U0)≤0°、-180°≤arg(3I 03 When / (3U0)≤0°, the integrated grounding protection device 10 controls the DL1 circuit breaker, DL2 circuit breaker and DL4 circuit breaker to open and disconnect all lines.

[0126] (2) When a ground fault occurs in collector line L5, the following judgment and protection methods are available: At time t1, 3U0≥U set 3I0≥I set 3I 02 ≥I set、 3I 04 ≥I set At this time, the zero-sequence voltage exceeds the limit, and the integrated grounding protection device 10 disconnects the DL circuit breaker, and the system switches from operating in the small resistance grounding mode to operating in the ungrounded mode; t1~t2 moment, the integrated ground protection device 10 detects again whether the criterion 3U0≥U set : (a) If 3U0≥U set : that is, 3U0 set : then it indicates that the collector line L5 occurs transient single-phase ground fault, and after the fault occurs, the collector line L5 automatically extinguishes arc, and the insulation is automatically restored, at this time the integrated ground protection device 10 controls the DL breaker to automatically close, and the system grounding mode is converted from non-grounded operation to small resistance grounding mode operation, and the system is restored to normal. This judgment mode can greatly improve the stability of system power supply.

[0127] (b) If 3U0≥U set : then it indicates that the collector line L5 occurs permanent ground fault, and the integrated ground protection device 10 does not execute the automatic closing instruction; at the same time, the integrated ground protection device 10 realizes accurate line selection according to the aforementioned criterion: 3I0=3I 02 =3I 04 ≥I set . At t2 moment, the integrated ground protection device 10 disconnects the corresponding breaker DL4, disconnects the ground fault corresponding collector line L5, and excludes the ground fault line. After the fault is removed, 3U0 set , at t3 moment, the integrated ground protection device 10 controls the DL breaker to automatically close.

[0128] When the above-mentioned collector line L5 ground fault is permanent ground fault, the corresponding DL breaker and DL4 breaker are disconnected, and the system is converted to non-grounded operation, at this time the original single-phase ground protection system has completely failed, but the integrated ground protection device 10 can still work normally.

[0129] When the system again occurs single-phase ground fault after the DL breaker and DL4 breaker are disconnected (on the basis of the collector line L5 ground fault), the criterion for judging line selection will use the amplitude and phase comparison method to select line, so as to remove the ground fault. For example: When the collector line L4 occurs single-phase ground fault, the amplitude and phase comparison criterion is: 3U0≥U set , 3I 03 ≥I set , -180°≤arg(3I 03 / (3U0)≤0°, when the above criterion is satisfied, the integrated ground protection device 10 controls the DL3 breaker to open, and removes the collector line L4.

[0130] When the ground fault line L3 occurs single-phase ground fault, the amplitude and phase comparison criterion is: 3U0≥U set , 3I 02≥I set , -180°≤arg(3I 02 ) / (3U0)≤0°, when the above criteria are met, the integrated ground protection device 10 controls the DL2 circuit breaker to open, and the ground line L3 is cut off.

[0131] When a single-phase ground fault occurs in the 35kV bus L1, the amplitude and phase comparison criterion is: 3U0≥U set , 3I 01 ≥I set , 3I 02 ≥I set , 3I 03 ≥I set , -180°≤arg(3I 01 ) / (3U0)≤0°, -180°≤arg(3I 02 ) / (3U0)≤0°, -180°≤arg(3I 03 ) / (3U0)≤0°, when the above criteria are met, the integrated ground protection device 10 controls the DL1 circuit breaker, the DL2 circuit breaker, and the DL3 circuit breaker to cut off all lines.

[0132] (3) When a single-phase ground fault occurs in the 35kV bus L1, the following judgment and protection method is used: The integrated ground protection device 10 can determine whether this type of fault occurs according to the 35kV bus L1 single-phase ground fault determination condition. The 35kV bus L1 single-phase ground fault determination condition is: At t1, 3U0≥U set , 3I0≥I set , 3I 01 ≥I set , 3I 02 ≥I set , 3I 03 ≥I set , 3I 04 ≥I set , -180°≤arg(3I 01 ) / (3U0)≤0°, -180°≤arg(3I 02 ) / (3U0)≤0°, -180°≤arg(3I 03 ) / (3U0)≤0°, -180°≤arg(3I 04 ) / (3U0)≤0°, since the bus fault is mostly permanent, the integrated ground protection device 10 does not execute the DL automatic closing instruction; at the same time, the integrated ground protection device 10 can be used as a backup protection for the bus protection, and at t2, the DL1 circuit breaker, the DL2 circuit breaker, the DL3 circuit breaker, and the DL4 circuit breaker are opened.

[0133] (4) Grounding transformer line L3 occurs grounding fault, there are the following judgment and protection method: The integrated grounding protection device 10 can determine whether the type of fault occurs according to the grounding transformer line L3 grounding fault determination condition. Wherein, the grounding transformer line L3 grounding fault type determination condition is: 3U0≥U at t1 time set , 3I0≥I set Since the grounding transformer line fault is mostly permanent fault, the integrated grounding protection device 10 does not execute DL automatic closing instruction; the integrated grounding protection device 10 executes DL2 opening instruction at t2 time.

[0134] (5) Grounding transformer line L3 occurs phase-to-phase fault, there are the following judgment and protection method: The integrated grounding protection device 10 can determine whether the type of fault occurs according to the grounding transformer line L3 phase-to-phase fault determination condition. Wherein, the grounding transformer line L3 phase-to-phase fault type determination condition is: Phase current I A -I0≥I set or I B -I0≥I set or I C -I0≥I set (3I0=I A +I B +I C, Calculated by the integrated grounding protection device 10 internally), the integrated grounding protection device 10 executes DL2 opening instruction at t2 time.

[0135] The integrated grounding protection device in the embodiment is in the form of a functional unit, and the unit refers to an ASIC (Application Specific Integrated Circuit, Application Specific Integrated Circuit) circuit, a processor and a memory executing one or more software or fixed programs, and / or other devices that can provide the above functions.

[0136] The embodiment of the application also provides a computer device with the integrated grounding protection device shown above.

[0137] Please refer to Figure 9 , Figure 9 is a structural schematic diagram of a computer device provided by an optional embodiment of the application, as Figure 9As shown, the computer device includes one or more processors 10, memory 20, and interfaces 50 for external devices such as modems and network interfaces. The one or more processors 10 can be central processing units, network processing units, or both, or some combination thereof. The memory 20 can include volatile memory, non-volatile memory, or both, and can include one or more memory units 20. The one or more memory units 20 can be internal to the computer device, external to the computer device, or both. As illustrated, the computer device includes several interfaces 50, including an interface to one or more external storage devices 60 and an interface to display 70. The interface to the one or more external storage devices 60 can be a floppy disk controller, a drive controller, or both, or some combination thereof. The interface to the display 70 can be a graphics controller. The one or more external storage devices 60 and the display 70 can be coupled either directly to the interfaces 50 or, as is illustrated, through intervening I / O controllers 80. Figure 9 The processor 10 is used as an example in the following description.

[0138] The processor 10 can be a central processing unit, a network processing unit, or both, or some combination thereof. The processor 10 can further include hardware chips. The hardware chips can be application specific integrated circuits, programmable logic devices, or some combination thereof. The programmable logic devices can be complex programmable logic devices, field programmable logic devices, general array logic, or some combination thereof.

[0139] The memory 20 stores instructions that can be executed by the at least one processor 10 to cause the at least one processor 10 to perform the methods illustrated by the above embodiments.

[0140] The memory 20 can include a program storage area and a data storage area. The program storage area can store an operating system, application programs, and the like for use by the at least one processor 10. The data storage area can store data created by the computer device, as well as data used by the at least one processor 10. The memory 20 can include both a volatile memory and a non-volatile memory. The volatile memory can include random access memory (RAM) including a dynamic random access memory (DRAM), a static random access memory (SRAM), and the like. The non-volatile memory can include a read only memory (ROM), a programmable read only memory (PROM), an erasable programmable read only memory (EPROM), an electrically erasable programmable read only memory (EEPROM), a flash memory, a solid state drive (SSD), and the like. The memory 20 can include a combination of volatile and non-volatile memory.

[0141] The memory 20 can include a volatile memory, such as random access memory (RAM), and a non-volatile memory, such as flash memory, a hard disk drive, or a solid state drive. The memory 20 can include a combination of volatile and non-volatile memory.

[0142] The computer device also includes input devices 30 and output devices 40. The input devices 30 and the output devices 40 can be connected to the one or more processors 10 via the interfaces 50,Figure 9 The bus connection is taken as an example.

[0143] The input device 30 can receive inputted digital or character information, and generate key signal input related to user settings and function control of the computer device, such as touch screen, keypad, mouse, trackpad, touchpad, pointing stick, one or more mouse buttons, trackball, joystick, etc. The output device 40 can include display device, auxiliary lighting device (e.g. LED), and tactile feedback device (e.g. vibration motor), etc. The display device includes but is not limited to liquid crystal display, light emitting diode, display and plasma display. In some alternative embodiments, the display device can be a touch screen.

[0144] The embodiments of the present application also provide a computer readable storage medium, the method according to the embodiments of the present application can be implemented in hardware, firmware, or recorded in a storage medium, or stored in a remote storage medium or a non-transitory machine readable storage medium and downloaded to a local storage medium, so that the method described herein can be processed by such software on a storage medium using a general purpose computer, a special purpose processor or programmable or special purpose hardware. The storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk or a solid state disk, etc. Further, the storage medium can also include a combination of the above-mentioned memories. It can be understood that the computer, processor, microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code, when the software or computer code is accessed and executed by the computer, processor or hardware, the method shown in the above embodiments is implemented.

[0145] Part of the present application can be applied as a computer program product, for example, computer program instructions, when executed by a computer, the operation of the computer can invoke or provide the method and / or technical solutions according to the present application. Those skilled in the art should understand that the form of computer program instructions in computer readable medium includes but is not limited to source file, executable file, installation package file, etc. Correspondingly, the way of computer program instructions executed by computer includes but is not limited to: the computer directly executes the instructions, or the computer compiles the instructions and then executes the corresponding compiled program, or the computer reads and executes the instructions, or the computer reads and installs the instructions and then executes the corresponding installed program. Here, the computer readable medium can be any available computer readable storage medium or communication medium accessible to the computer.

[0146] While embodiments of the application have been described in connection with the preferred embodiments of the various figures, those of ordinary skill in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the application, and that such modifications and changes fall within the scope of the appended claims.

Claims

1. A comprehensive protection system for single-phase grounding faults in a new energy power plant, characterized in that, include: Line telemetry module, integrated grounding protection equipment, automatic circuit breaker device, among which, The line telemetry module is used to detect the current and voltage of each line in the power station; The integrated grounding protection device is used to switch to the corresponding mode according to the neutral point setting method of the power station; based on the current and voltage of each line and the opening and closing position status of the power station circuit breaker, it performs logical operations to determine whether a grounding fault has occurred; and issues a corresponding control signal according to the determination result. The automatic circuit breaker device is connected in series with the grounding branch of the power station. When the automatic circuit breaker device receives the control signal, it closes or opens to realize the operation of the power station in grounded or ungrounded mode.

2. The integrated protection system for single-phase grounding faults in new energy power plants according to claim 1, characterized in that, The integrated grounding protection device includes: an analog signal input module, a digital signal input module, an analog-to-digital conversion module, a logic judgment module, a digital signal output module, a mode conversion module, and a human-machine interaction module. The analog signal input module is used to acquire the current and voltage signals of the current transformer and voltage transformer, and transmit the current and voltage signals to the analog-to-digital conversion module; The switch signal input module is used to collect the circuit breaker opening and closing position status of the corresponding circuit breaker and transmit the circuit breaker opening and closing position status to the logic judgment module. The analog-to-digital converter module is used to convert the analog signal from the analog signal input module into a digital signal, and transmit the digital signal to the logic judgment module; The logic judgment module compares the amplitude and phase of the current and voltage of each line obtained by the line telemetry module, and combines the circuit breaker opening and closing position status to determine whether a ground fault has occurred through logic calculation. The switch signal output module is used to receive the logic judgment result of the logic judgment module and to output the corresponding circuit breaker control signal. The mode conversion module is used to switch the working mode of the integrated grounding protection device according to the neutral point setting method of the power station. The human-computer interaction module is used for manual control and searching of the system's operating status. At the same time, staff can use the human-computer interaction module to switch the working modes of the mode conversion module.

3. The integrated protection system for single-phase grounding faults in new energy power plants according to claim 2, characterized in that, The operating modes include: grounding mode of new energy power stations without main transformer step-up via grounding transformer with reduced resistance, grounding mode of new energy power stations with main transformer step-up via main transformer low-voltage side neutral point resistance, and grounding mode of new energy power stations with main transformer step-up via grounding transformer with reduced resistance.

4. A comprehensive protection method for single-phase grounding faults in new energy power plants, characterized in that, The method, applied to the integrated grounding protection device of claim 3, comprises: The current and voltage of each line in the power station are obtained from the remote sensing module. Switch to the corresponding mode according to the neutral point setting method of the power station; Based on the amplitude and phase of the current and voltage of each line, and the opening and closing position of the circuit breaker of the power station, a ground fault is determined through logical operation, and a corresponding control signal is issued according to the determination result. The control signal is used to control the automatic circuit breaker to close or open, so as to realize the operation of the power station in grounded or ungrounded mode.

5. The comprehensive protection method for single-phase grounding faults in new energy power plants according to claim 4, characterized in that, The power station includes collector lines, grounding lines, grounding transformer branches, transmission lines, busbars and other lines.

6. The comprehensive protection method for single-phase grounding faults in new energy power plants according to claim 5, characterized in that, For any collector line, the process of issuing the corresponding control signal based on the judgment result includes: When the operating mode is a new energy power station without main transformer step-up and grounded through a grounding transformer with low resistance, if the bus zero-sequence voltage amplitude is greater than or equal to the preset bus voltage threshold, the zero-sequence current amplitude on the grounding line is greater than or equal to the preset grounding current threshold, the zero-sequence current amplitude of the grounding transformer branch is greater than or equal to the preset grounding transformer current threshold, and the zero-sequence current amplitude of the collector line is greater than or equal to the preset collector line current threshold, then the automatic circuit breaker device is controlled to open; after a preset time, if the bus zero-sequence voltage amplitude is greater than or equal to the preset bus voltage threshold, then the automatic circuit breaker device is controlled to remain in the open state, and the circuit breaker on the collector line is controlled to open; otherwise, the automatic circuit breaker device is controlled to close. When the operating mode is the new energy power station with voltage boosted by the main transformer and grounded through the neutral point resistance of the low-voltage side of the main transformer, if the amplitude of the zero-sequence voltage of the bus is greater than or equal to the preset bus voltage threshold, the amplitude of the zero-sequence current on the grounding line is greater than or equal to the preset grounding current threshold, the amplitude of the zero-sequence current of the transmitting line is greater than or equal to the preset grounding transformer current threshold, and the amplitude of the zero-sequence current of the collector line is greater than or equal to the preset collector line current threshold, then the automatic circuit breaker device is controlled to open; after a preset time, if the amplitude of the zero-sequence voltage of the bus is greater than or equal to the preset bus voltage threshold, then the automatic circuit breaker device is controlled to remain in the open state, and the circuit breaker on the collector line is controlled to open; otherwise, the automatic circuit breaker device is controlled to close. When the operating mode is the new energy power station with voltage boosted by the main transformer and grounded through the grounding transformer with low resistance, if the zero-sequence voltage amplitude of the bus is greater than or equal to the preset bus voltage threshold, the zero-sequence current amplitude on the grounding line is greater than or equal to the preset grounding current threshold, the zero-sequence current amplitude of the grounding transformer branch is greater than or equal to the preset grounding transformer current threshold, and the zero-sequence current amplitude of the collector line is greater than or equal to the preset collector line current threshold, then the automatic circuit breaker device is controlled to open; after a preset time, if the zero-sequence voltage amplitude of the bus is greater than or equal to the preset bus voltage threshold, then the automatic circuit breaker device is controlled to remain in the open state, and the circuit breaker on the collector line is controlled to open; otherwise, the automatic circuit breaker device is controlled to close.

7. The comprehensive protection method for single-phase grounding faults in new energy power plants according to claim 6, characterized in that, When at least one collector line experiences a permanent single-phase ground fault, the process of issuing a corresponding control signal based on the judgment result further includes: For any unfaulted collector line, if the zero-sequence voltage amplitude of the bus is greater than or equal to the preset bus voltage threshold, the zero-sequence current amplitude of the collector line is greater than or equal to the preset collector line current threshold, and the phase angle of the collector line is greater than or equal to -180° and less than or equal to 0°, then the circuit breaker on the collector line is controlled to open. For any other line, if the zero-sequence voltage amplitude of the bus is greater than or equal to the preset bus voltage threshold, the zero-sequence current amplitude of the other line is greater than or equal to the preset current threshold of the other line, and the phase angle of the other line is greater than or equal to -180° and less than or equal to 0°, then the circuit breaker on that other line is controlled to open.

8. The comprehensive protection method for single-phase grounding faults in new energy power plants according to any one of claims 6 or 7, characterized in that, The process of issuing corresponding control signals based on the judgment result further includes: If the zero-sequence voltage amplitude of the busbar is greater than or equal to the preset busbar voltage threshold, the zero-sequence current amplitude of the transmitting line is greater than or equal to the preset transmitting line current threshold, the zero-sequence current amplitude of the grounding transformer branch is greater than or equal to the preset grounding transformer current threshold, and the zero-sequence current amplitude of all collector lines is greater than or equal to the collector line current threshold, and at the same time the phase angle of the transmitting line, the grounding transformer branch, and all collector lines is greater than or equal to -180° and less than or equal to 0°, then the circuit breakers on the transmitting line, the grounding transformer branch, and all collector lines will be opened.

9. The comprehensive protection method for single-phase grounding faults in new energy power plants according to claim 5, characterized in that, For any other line, the process of issuing the corresponding control signal based on the judgment result includes: When the operating mode is a new energy power station without main transformer step-up and grounded through a grounding transformer with low resistance, if the bus zero-sequence voltage amplitude is greater than or equal to the preset bus voltage threshold, the zero-sequence current amplitude on the grounding line is greater than or equal to the preset grounding current threshold, the zero-sequence current amplitude of the grounding transformer branch is greater than or equal to the preset grounding transformer current threshold, and the zero-sequence current amplitude of other lines is greater than or equal to the preset collector line current threshold, then the automatic circuit breaker device is controlled to open; after a preset time, if the bus zero-sequence voltage amplitude is greater than or equal to the preset bus voltage threshold, then the automatic circuit breaker device is controlled to remain in the open state, and the circuit breakers on the other lines are controlled to open; otherwise, the automatic circuit breaker device is controlled to close. When the operating mode is the new energy power station with voltage boosted by the main transformer and grounded through the neutral point resistance of the low-voltage side of the main transformer, if the zero-sequence voltage amplitude of the bus is greater than or equal to the preset bus voltage threshold, the zero-sequence current amplitude on the grounding line is greater than or equal to the preset grounding current threshold, the zero-sequence current amplitude of the transmitting line is greater than or equal to the preset grounding transformer current threshold, and the zero-sequence current amplitude of other lines is greater than or equal to the preset collector line current threshold, then the automatic circuit breaker device is controlled to open; after a preset time, if the zero-sequence voltage amplitude of the bus is greater than or equal to the preset bus voltage threshold, then the automatic circuit breaker device is controlled to remain in the open state, and the circuit breakers on the other lines are controlled to open; otherwise, the automatic circuit breaker device is controlled to close. When the operating mode is the new energy power station with voltage boosted by the main transformer and grounded by the grounding transformer with low resistance, if the zero-sequence voltage amplitude of the bus is greater than or equal to the preset bus voltage threshold, the zero-sequence current amplitude on the grounding line is greater than or equal to the preset grounding current threshold, the zero-sequence current amplitude of the grounding transformer branch is greater than or equal to the preset grounding transformer current threshold, and the zero-sequence current amplitude of other lines is greater than or equal to the preset collector line current threshold, then the automatic circuit breaker device is controlled to open; after a preset time, if the zero-sequence voltage amplitude of the bus is greater than or equal to the preset bus voltage threshold, then the automatic circuit breaker device is controlled to remain in the open state, and the circuit breakers on the other lines are controlled to open; otherwise, the automatic circuit breaker device is controlled to close.

10. The comprehensive protection method for single-phase grounding faults in new energy power plants according to claim 5, characterized in that, When at least one other line experiences a permanent single-phase ground fault, the process of issuing a corresponding control signal based on the judgment result further includes: For any collector line, if the zero-sequence voltage amplitude of the bus is greater than or equal to the preset bus voltage threshold, the zero-sequence current amplitude of the collector line is greater than or equal to the preset collector line current threshold, and the phase angle of the collector line is greater than or equal to -180° and less than or equal to 0°, then the circuit breaker on the collector line is controlled to open.

11. The comprehensive protection method for single-phase grounding faults in new energy power plants according to any one of claims 9 or 10, characterized in that, The process of issuing corresponding control signals based on the judgment result further includes: If the zero-sequence voltage amplitude of the busbar is greater than or equal to the preset busbar voltage threshold, the zero-sequence current amplitude of the transmitting line is greater than or equal to the preset transmitting line current threshold, the zero-sequence current amplitude of the grounding transformer branch is greater than or equal to the preset grounding transformer current threshold, and the zero-sequence current amplitude of all collector lines is greater than or equal to the collector line current threshold, and at the same time the phase angle of the transmitting line, the grounding transformer branch, and all collector lines is greater than or equal to -180° and less than or equal to 0°, then the circuit breakers on the transmitting line, the grounding transformer branch, and all collector lines will be opened.

12. The comprehensive protection method for single-phase grounding faults in new energy power plants according to claim 5, characterized in that, For grounding transformer lines, the process of issuing corresponding control signals based on the judgment result includes: If the zero-sequence voltage amplitude of the busbar is greater than or equal to the preset busbar voltage threshold, and the zero-sequence current amplitude on the grounding line is greater than or equal to the preset grounding current threshold, then the automatic circuit breaker device is controlled to remain in the open state. After a preset time, the circuit breaker on the grounding transformer line is controlled to open. If the difference between the amplitude of any phase current of the busbar and the amplitude of its zero-sequence current is greater than or equal to the preset current difference, the circuit breaker on the grounding transformer line will be controlled to trip.

Images