A novel risk warning device for 10kV switchgear room in substations

Abstract

This invention proposes a novel risk warning device for 10kV switchgear rooms in substations, used to warn of potential hazards in high-voltage switchgear within the switchgear room. The device includes a switchgear fault detector for monitoring the voltage transformers of the high-voltage switchgear and a leakage current sensor connected to them. The leakage current sensor is a Hall effect current transformer assembly installed at the neutral point of the voltage transformer (PT). The switchgear fault detector collects the secondary voltage of its voltage transformer and the current of the Hall effect current transformer assembly, analyzes the results using a logic program algorithm to determine if there are potential hazards in the switchgear room, and issues a warning based on the analysis results. This invention enables early warning of potential hazards in high-voltage switchgear within the switchgear room.

Description

Technical Field

[0001] This invention relates to the field of substation operation and maintenance technology, and in particular to a novel risk warning device for a 10kV switch room in a substation. Background Technology

[0002] High-voltage switchgear equipment is widely used in power systems and is centrally installed in switch rooms. In recent years, accidents involving switchgear equipment have become more prominent during operation and maintenance, seriously affecting equipment, power grid, and personal safety.

[0003] The safety logic of high-voltage switchgear is described from a physical data perspective as: the insulation distance between energized parts or between energized parts and the grounding electrode, and the withstand voltage level of the insulation medium inside the cabinet. The safety distance between energized parts inside the cabinet must meet the regulatory requirements, specifically including the distance between energized conductors of different phases and the distance between conductors and the grounding electrode. The grounding electrode includes the cabinet body, operating rod, and grounding down conductor. In actual operation, when products arrive at the site for installation, there have been instances where safety distances did not meet regulatory requirements, and the safety distance between the moving contact of the disconnector and the cabinet body was insufficient after being opened. There have even been instances where the safety distance between energized parts and the operating rod was insufficient, seriously threatening the safety of operating personnel.

[0004] The supporting insulators inside high-voltage switchgear should meet the requirements for long-term high-voltage operation and have the ability to withstand system overvoltages for short periods. However, in actual operation, some insulators, although they have passed all factory tests, commissioning tests, and routine tests, still suffer insulation damage after long-term energized operation when an overvoltage occurs in the system.

[0005] Furthermore, because the power equipment is installed inside high-voltage switchgear, and the switch room where the switchgear is located is dark and enclosed, early-stage deterioration of the power equipment is not easily detected. Maintenance personnel cannot effectively identify potential hazards in the high-voltage switchgear equipment while working in the switch room. This directly creates work risks for maintenance personnel.

[0006] To address the above problems, this invention proposes a solution that aims to provide risk alerts for switchgear rooms by collecting bus voltage and grounding current data. Summary of the Invention

[0007] This invention proposes a novel risk warning device for 10kV switchgear rooms in substations, which can provide early warning of potential dangers to high-voltage switchgear inside the switchgear room.

[0008] The present invention adopts the following technical solution.

[0009] A novel risk warning device for 10kV switchgear rooms in substations is disclosed, used to warn of potential hazards in high-voltage switchgear within the switchgear room. The device includes a switchgear fault detector for monitoring the voltage transformers of the high-voltage switchgear and a leakage current sensor connected to them. The leakage current sensor is a Hall effect current transformer assembly installed at the neutral point of the voltage transformer (PT). The switchgear fault detector collects the secondary voltage of its voltage transformer and the current of the Hall effect current transformer assembly, analyzes the results using a logic program algorithm to determine if there are potential hazards in the switchgear room, and issues a warning based on the analysis results.

[0010] The Hall current transformer assembly is installed at the grounding electrode of the voltage transformer PT to detect the grounding current of the grounding electrode.

[0011] The Hall current transformer assembly includes a first Hall current transformer and a second Hall current transformer arranged sequentially in the direction of the grounding current of the grounding body; the rated current of the first Hall current transformer is less than the rated current of the second Hall current transformer, and the current detection polarity is positive in the direction towards the ground.

[0012] The rated current of the first Hall current transformer is 1A; the rated current of the second Hall current transformer is 100A.

[0013] The switchgear fault instrument includes a current probe with a sampling rate of 500KSPS or higher, and a voltage probe with a sampling rate of 1KSPS or higher; the current probe and voltage probe are used to monitor the instantaneous short-cycle grounding current on the PT side of the high-voltage switchgear caused by an external line grounding fault.

[0014] The logic procedure for analyzing whether there are potential hazards in the current switch room includes the following logic: Logic S1: If the current direction of the grounding electrode is from the grounding point to PT, it is determined that the lightning wave has entered through the grounding grid of the grounding electrode. Regardless of the current magnitude, it is determined to be a fault state and an alarm signal is issued. Logic S2: When the current direction of the grounding electrode is from PT to the grounding point, if the current detected by the first Hall current transformer is below 0.8A, it is considered to be in a normal state. Logic S3: If the current direction of the grounding electrode is from the PT to the grounding point, and the current detected by the second current transformer is greater than 80A, then it is directly judged as a fault state. Logic S4: If the switchgear fault instrument detects a sudden change in the effective value of the PT voltage, and if the effective values ​​of the three-phase voltages are all on the rising channel, and the grounding current is greater than 0.8A and less than 80A, then it is determined that the equipment is powered on normally, or that the grounding current is normal due to the inconsistency of the three phases after the PT equipment is repaired and put back into operation. Logic S5: If the switchgear fault instrument detects a sudden change in the effective value of the PT voltage, and if the effective values ​​of the three-phase voltages are all in a decreasing channel, and the grounding current is greater than 0.8A and less than 80A, then it is determined that the equipment is in a normal power outage situation, or that the grounding current is normal due to the inconsistency of the three phases caused by the PT equipment being transferred for maintenance. Logic S6: If the switchgear fault instrument detects a sudden change in the effective value of the PT voltage, and if the three-phase voltage change trends are inconsistent, and the grounding current is greater than 0.8A and less than 80A, it is judged as a fault state caused by an external fault leading to a voltage drop, or as a fault state caused by the phase-to-phase voltage rising to 1.732 times the normal voltage, resulting in the breakdown of weak points in the phase-to-phase insulation. The risk warning device stops alarming once it receives a signal that the fault has disappeared.

[0015] When the risk warning device determines that a fault has occurred, it will issue a warning sound to remind maintenance personnel to stay away from the switchgear equipment. If the fault still exists before the fault state is reset, the warning sound will continue until 1 minute after the fault disappearance signal is received.

[0016] The triggering condition for the fault disappearance signal is that the three-phase voltage of the PT is 0 or at a normal value, and the grounding current is less than 0.8A.

[0017] The switchgear fault instrument and leakage current sensor are located at the PT position of the lower cabinet of the high-voltage switchgear in the switch room.

[0018] This invention assesses the switchgear status by collecting the grounding current and secondary voltage signals of the PT. Once an abnormality is detected, it alerts maintenance personnel to maintain a sufficient energized distance from the equipment or not to enter the switch room via sound, thereby improving the safety of maintenance personnel. Attached Figure Description

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Appendix Figure 1 This is a schematic diagram illustrating an embodiment of the present invention; Appendix Figure 2 This is a schematic diagram of the Hall current transformer assembly installed on the grounding body in this invention; Appendix Figure 3 This is a schematic diagram of the hardware principle of the switchgear fault detector; Appendix Figure 4 This is a schematic diagram of logic S1 of the present invention; Appendix Figure 5 This is a schematic diagram of the logical judgment principle of the present invention; In the diagram: 1-Switch cabinet fault instrument; 2-Hall current transformer assembly; 3-Grounding electrode; 4-First Hall current transformer; 5-Second Hall current transformer; Detailed Implementation

[0020] As shown in the figure, a novel risk warning device for a 10kV switchgear room in a substation is used to warn of potential hazards in the high-voltage switchgear room. The warning device includes a switchgear fault detector for monitoring the voltage transformer of the high-voltage switchgear and a leakage current sensor connected to it. The leakage current sensor is a Hall current transformer assembly installed at the neutral point of the voltage transformer (PT). The switchgear fault detector collects the secondary voltage of its voltage transformer and the current of the Hall current transformer assembly, analyzes the results of the logic program algorithm to determine whether there are potential hazards in the switchgear room, and issues a warning based on the analysis results.

[0021] The Hall current transformer assembly is installed at the grounding electrode of the voltage transformer PT to detect the grounding current of the grounding electrode.

[0022] The Hall current transformer assembly includes a first Hall current transformer and a second Hall current transformer arranged sequentially in the direction of the grounding current of the grounding body; the rated current of the first Hall current transformer is less than the rated current of the second Hall current transformer, and the current detection polarity is positive in the direction towards the ground.

[0023] The rated current of the first Hall current transformer is 1A; the rated current of the second Hall current transformer is 100A.

[0024] The switchgear fault instrument includes a current probe with a sampling rate of 500KSPS or higher, and a voltage probe with a sampling rate of 1KSPS or higher; the current probe and voltage probe are used to monitor the instantaneous short-cycle grounding current on the PT side of the high-voltage switchgear caused by an external line grounding fault.

[0025] The logic procedure for analyzing whether there are potential hazards in the current switch room includes the following logic: Logic S1: If the current direction of the grounding electrode is from the grounding point to PT, it is determined that the lightning wave has entered through the grounding grid of the grounding electrode. Regardless of the current magnitude, it is determined to be a fault state and an alarm signal is issued. Logic S2: When the current direction of the grounding electrode is from PT to the grounding point, if the current detected by the first Hall current transformer is below 0.8A, it is considered to be in a normal state. Logic S3: If the current direction of the grounding electrode is from the PT to the grounding point, and the current detected by the second current transformer is greater than 80A, then it is directly judged as a fault state. Logic S4: If the switchgear fault instrument detects a sudden change in the effective value of the PT voltage, and if the effective values ​​of the three-phase voltages are all on the rising channel, and the grounding current is greater than 0.8A and less than 80A, then it is determined that the equipment is powered on normally, or that the grounding current is normal due to the inconsistency of the three phases after the PT equipment is repaired and put back into operation. Logic S5: If the switchgear fault instrument detects a sudden change in the effective value of the PT voltage, and if the effective values ​​of the three-phase voltages are all in a decreasing channel, and the grounding current is greater than 0.8A and less than 80A, then it is determined that the equipment is in a normal power outage situation, or that the grounding current is normal due to the inconsistency of the three phases caused by the PT equipment being transferred for maintenance. Logic S6: If the switchgear fault instrument detects a sudden change in the effective value of the PT voltage, and if the three-phase voltage change trends are inconsistent, and the grounding current is greater than 0.8A and less than 80A, it is judged as a fault state caused by an external fault leading to a voltage drop, or as a fault state caused by the phase-to-phase voltage rising to 1.732 times the normal voltage, resulting in the breakdown of weak points in the phase-to-phase insulation. The risk warning device stops alarming once it receives a signal that the fault has disappeared.

[0026] When the risk warning device determines that a fault has occurred, it will issue a warning sound to remind maintenance personnel to stay away from the switchgear equipment. If the fault still exists before the fault state is reset, the warning sound will continue until 1 minute after the fault disappearance signal is received.

[0027] The triggering condition for the fault disappearance signal is that the three-phase voltage of the PT is 0 or at a normal value, and the grounding current is less than 0.8A.

[0028] The switchgear fault instrument and leakage current sensor are located at the PT position of the lower cabinet of the high-voltage switchgear in the switch room.

[0029] In this example, a switchgear fault detector and a leakage current sensor are installed in the lower cabinet of the PT cabinet, and a Hall current transformer is installed at the neutral point of the voltage transformer. The function of the switchgear fault detector is to collect the secondary voltage of its voltage transformer and the current of its Hall current transformer, analyze the results through an algorithm, and issue an audible warning signal.

[0030] Considering that 10kV voltage imbalance is a normal operating condition of the system and there is a certain grounding current, two different Hall current transformers are set to achieve the difference judgment. One Hall current transformer is set to a rated current of 1A and the other Hall current transformer is set to 100A, and the current detection polarity is positive towards the ground.

[0031] In the sampling design of the switchgear fault instrument, considering that when there is an external line grounding fault, a momentary grounding current will be generated on the PT side, and its cycle is short, the sampling rate of the current probe is set to above 500KSPS and the sampling rate of the voltage probe is set to above 1KSPS.

[0032] In the event of a fault, the equipment will emit an audible warning to maintenance personnel to move away from the switchgear. This audible warning will last for 1 minute. If the fault persists before the fault condition is resolved, the audible warning will continue until a fault disappearance signal is received 1 minute later. The fault disappearance signal is triggered when the three-phase voltage is 0 or at a normal value, and the grounding current is less than 0.8A.

Claims

1. A novel risk warning device for a 10kV switchgear room in a substation, used to warn of potential hazards to high-voltage switchgear inside the switchgear room, characterized in that: The alerting device includes a switchgear fault detector for monitoring the voltage transformer of the high-voltage switchgear and a leakage current sensor connected thereto; the leakage current sensor is a Hall current transformer assembly installed at the neutral point of the voltage transformer PT. The switchgear fault instrument collects the secondary voltage of its voltage transformer and the current of the Hall current transformer assembly, analyzes the results of the logic program algorithm to determine whether there is a potential danger in the current switchgear room, and issues an early warning based on the analysis results. The Hall current transformer assembly is installed at the grounding electrode of the voltage transformer PT to detect the grounding current of the grounding electrode. The Hall current transformer assembly includes a first Hall current transformer and a second Hall current transformer arranged sequentially in the direction of the grounding current of the grounding body. The rated current of the first Hall current transformer is less than the rated current of the second Hall current transformer, and the current detection polarity is positive when it is facing the ground. The switchgear fault instrument includes a current probe with a sampling rate of 500KSPS or higher, and a voltage probe with a sampling rate of 1KSPS or higher; the current probe and voltage probe are used to monitor the instantaneous short-cycle grounding current on the PT side of the high-voltage switchgear caused by an external line grounding fault. The logic procedure for analyzing whether there are potential hazards in the current switch room includes the following logic: Logic S1: If the current direction of the grounding electrode is from the grounding point to PT, it is determined that the lightning wave has entered through the grounding grid of the grounding electrode. Regardless of the current magnitude, it is determined to be a fault state and an alarm signal is issued. Logic S2: When the current direction of the grounding electrode is from PT to the grounding point, if the current detected by the first Hall current transformer is below 0.8A, it is considered to be in a normal state. Logic S3: If the current direction of the grounding electrode is from the PT to the grounding point, and the current detected by the second current transformer is greater than 80A, then it is directly judged as a fault state. Logic S4: If the switchgear fault instrument detects a sudden change in the effective value of the PT voltage, and if the effective values ​​of the three-phase voltages are all on the rising channel, and the grounding current is greater than 0.8A and less than 80A, then it is determined that the equipment is powered on normally, or that the grounding current is normal due to the inconsistency of the three phases after the PT equipment is repaired and put back into operation. Logic S5: If the switchgear fault instrument detects a sudden change in the effective value of the PT voltage, and if the effective values ​​of the three-phase voltages are all in a decreasing channel, and the grounding current is greater than 0.8A and less than 80A, then it is determined that the equipment is in a normal power outage situation, or that the grounding current is normal due to the inconsistency of the three phases caused by the PT equipment being transferred for maintenance. Logic S6: If the switchgear fault instrument detects a sudden change in the effective value of the PT voltage, and if the three-phase voltage change trends are inconsistent, and the grounding current is greater than 0.8A and less than 80A, it is judged as a fault state caused by an external fault leading to a voltage drop, or as a fault state caused by the phase-to-phase voltage rising to 1.732 times the normal voltage, resulting in the breakdown of weak points in the phase-to-phase insulation. The risk warning device stops alarming once it receives a signal that the fault has disappeared.

2. The novel risk warning device for a 10kV switchgear room in a substation according to claim 1, characterized in that: The rated current of the first Hall current transformer is 1A; the rated current of the second Hall current transformer is 100A.

3. A novel risk warning device for a 10kV switchgear room in a substation according to claim 1, characterized in that: When the risk warning device determines that a fault has occurred, it will issue a warning sound to remind maintenance personnel to stay away from the switchgear equipment. If the fault still exists before the fault state is reset, the warning sound will continue until 1 minute after the fault disappearance signal is received.

4. A novel risk warning device for a 10kV switchgear room in a substation according to claim 1, characterized in that: The triggering condition for the fault disappearance signal is that the three-phase voltage of the PT is 0 or at a normal value, and the grounding current is less than 0.8A.

5. A novel risk warning device for a 10kV switchgear room in a substation according to claim 1, characterized in that: The switchgear fault instrument and leakage current sensor are located at the PT position of the lower cabinet of the high-voltage switchgear in the switch room.

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