Rapid gas protection system for transformer

Abstract

The invention relates to a transformer rapid gas protection system which comprises a plurality of gas relays and connecting pipes, the connecting pipes are designed between a transformer body and an oil conservator, the gas relay A is close to the side of the transformer body, the gas relay B is close to the side of the oil conservator, and gas diffusion time sequence detection is achieved through physical position differences. According to the protection system, the corresponding light gas action contacts and the corresponding heavy gas action contacts are connected to the non-electric-quantity protection device, and a control program of the non-electric-quantity protection device can be correspondingly upgraded and modified. The system inherits the advantages of simple structure and strong interference resistance of a traditional gas relay, overcomes the defects of single triggering and fixed value rigidity of the traditional gas relay, adopts dual-relay cooperative detection, intelligent time window management, hierarchical action logic and voltage level adaptive setting, and has high reliability and high reliability on the premise of being completely compatible with the existing relay structure. The sensitivity of light gas protection of the transformer is improved, and the maloperation rate is reduced.

Description

Technical Field

[0001] This invention relates to the field of electrical automation technology, specifically to a transformer fast gas protection system. Background Technology

[0002] During normal operation of a transformer charger, the speed and characteristics of fault development vary. During the instantaneous charging of the transformer, the inrush current is relatively high, making it easier for faults or existing defects to develop at a faster pace. However, the light gas protection function of existing gas relays cannot distinguish the operating mode or adjust the protection strategy. Therefore, it is possible to consider adopting an effective combination method that can reflect the rate of increase in gas volume during the transformer charging stage, thereby effectively determining the nature of the fault development inside the transformer during this dangerous stage and isolating the fault in a timely manner.

[0003] Furthermore, due to the extremely high voltage of ultra-high voltage main transformers, internal anomalies or faults develop rapidly under the influence of ultra-high voltage electromagnetic fields. Existing regulations specifying the light gas protection action values ​​for gas relays and the method of first issuing a signal and then having operators inspect the site are no longer compatible with the fault development characteristics and cannot meet the needs for rapid fault diagnosis and handling. Therefore, this technical solution designs a fast light gas relay and a fast light gas integrated protection system. The aim is to reduce the light gas action value according to the voltage level, improve the sensitivity of existing light gas protection systems, quickly isolate faults, and prevent the accident from escalating. Summary of the Invention

[0004] The purpose of this invention is to provide a fast gas protection system for transformers. To achieve the above objective, the technical solution of this invention is as follows.

[0005] A transformer fast gas protection system includes a gas relay and a connecting pipe. The connecting pipe, located between the transformer body and the oil conservator, includes gas relays A and B. Gas relay A, closer to the transformer body, activates both light and heavy gas functions, while gas relay B, closer to the oil conservator, activates only light gas and removes the heavy gas baffle. The timing detection of gas diffusion is achieved by adjusting the physical positional differences. The light gas A contact of gas relay A is connected to the light gas input terminal of a non-electrical quantity protection device, and the light gas B contact of gas relay B is connected to the spare input terminal 1 of the non-electrical quantity protection device. The closed and open contacts of the power supply side circuit breaker of the transformer body are connected to spare input terminals 2 and 3, respectively. An oil temperature sensor on the transformer body directly monitors the temperature; the sensor must be installed near gas relay A, at a distance of ≤1m from the relay.

[0006] The protection system includes an operation and anomaly judgment unit. This unit sets time thresholds T1 and T2 based on the transformer voltage level. T1 is the open window time after the light gas A action, corresponding to 30 minutes for 1000kV and 60 minutes for 220kV; T2 is the accelerated tripping time after the circuit breaker closes, corresponding to 60 minutes for 1000kV and 90 minutes for 220kV. The protection system incorporates an oil temperature compensation coefficient to dynamically calibrate the T1 and T2 timing thresholds in conjunction with the oil temperature signal and the gas signal. When light gas A acts and its duration does not exceed the set value T1, a trip is triggered if light gas B acts. When the duration of light gas A's action reaches T1, only an alarm signal is issued if light gas B does not act.

[0007] Furthermore, the operating setting values ​​of light gas A and light gas B range from 260ml to 290ml, with a increment of 1-1.5ml. The setting value decreases as the voltage level increases, i.e., 260ml for 1000kV and 290ml for 220kV.

[0008] Furthermore, the protection system includes a circuit breaker status judgment module. When the high-voltage side circuit breaker of the transformer changes from the closed position to the open position, the tripping is directly triggered if the light gas A action is activated within time T2.

[0009] Furthermore, the protection system includes a partial discharge detection module, which collects partial discharge signals inside the transformer through a high-frequency current transformer (HFCT), an ultra-high frequency (UHF) sensor, or an ultrasonic AE sensor, and sends the signals to the non-electrical protection device in the form of hard contacts.

[0010] Furthermore, the oil conservator outlet is equipped with an independent mechanical pressure relief valve interlocking device as a backup for heavy gas.

[0011] A transformer fast gas protection system is disclosed. The protection system includes an input module and an output module. The input module and the output module work together through an operation and anomaly judgment unit to achieve fast response and graded tripping of light gas protection.

[0012] Furthermore, the protection system includes a high-voltage side double trip contact, a medium-voltage side single trip contact, and a low-voltage side double branch trip contact to achieve multi-circuit redundant tripping. The high-voltage side double trip contact is a double-redundant trip contact to ensure reliable disconnection of the high-voltage side circuit breaker. The medium-voltage side single trip contact is used to disconnect the medium-voltage side circuit breaker. For the double-branch low-voltage side structure, it controls the two low-voltage circuit breakers respectively.

[0013] Furthermore, the input module includes the acquisition of the status of light gas A contact, the status of light gas B contact, the closed position status of the transformer power supply side circuit breaker, and the open position status of the transformer power supply side circuit breaker. The input module transmits the above signals to the operation and anomaly judgment unit, and triggers the protection logic through timing analysis and status combination.

[0014] Furthermore, the output module performs tripping or alarm operations based on the logical judgment result, and directly drives the tripping coil or signal relay based on the hard contact output.

[0015] Furthermore, the light gas action value collected by the input module and the tripping delay of the output module are dynamically adjusted according to the voltage level.

[0016] Furthermore, the non-electrical protection device integrates a human-machine interface, supports setting value adjustment, action record query and communication interface transmission, and is configured with light gas action alarm, fast light gas comprehensive alarm and device abnormality alarm hard contact output.

[0017] This invention differs significantly from existing single-relay solutions through dual-relay collaborative detection, graded action logic, and voltage level adaptive setting. Furthermore, this invention uses existing relays, requiring no changes to the structure and principle of existing gas relays; only the corresponding light gas and heavy gas action contacts are connected to the non-electrical quantity protection device, and the corresponding non-electrical quantity protection device program is upgraded and modified.

[0018] The dual-relay timing verification mechanism in this invention effectively solves the problem of failure after a single trigger in traditional light gas protection. Furthermore, the accelerated tripping logic after closing fills the gap in rapid response to inrush current faults. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a conventional solution of the present invention.

[0020] Figure 2 This is a schematic diagram of the installation position of the gas relay of the present invention.

[0021] Figure 3 This is a schematic diagram of the system modules of the present invention.

[0022] Figure 4 This is a schematic diagram of embodiment 1 of the protection system of the present invention.

[0023] Figure 5 This is a schematic diagram of embodiment 2 of the protection system of the present invention. Detailed Implementation

[0024] The specific embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the specific embodiments and examples described herein are for illustration and explanation only and are not intended to limit the present invention.

[0025] Existing light gas protection technologies are as follows: Figure 1 As shown, a gas relay is installed on the connecting pipe between the transformer body and the oil conservator. Both its light gas protection and heavy gas protection functions are activated. The light gas contact of the gas relay is connected via a control cable to the corresponding light gas protection input of the existing non-electrical quantity protection device. When the light gas contact of the gas relay is closed, the non-electrical quantity protection device activates and sends a light gas protection alarm signal. Similarly, the heavy gas contact of the gas relay is connected via a control cable to the corresponding heavy gas protection input of the existing non-electrical quantity protection device. When the heavy gas contact of the heavy gas relay is closed, the non-electrical quantity protection device activates and sends a heavy gas protection alarm signal, tripping the circuit breakers on each side of the main transformer and simultaneously sending a heavy gas protection alarm signal. It can be seen that in the existing technical solution, the light gas protection only activates once and sends a light gas protection alarm signal. If gas is released again after the transformer has issued the light gas protection alarm signal, the light gas protection will not activate and send a corresponding alarm signal or trip the corresponding circuit breaker. Therefore, traditional light gas protection systems can only issue a single alarm and cannot continuously monitor the fault development process. If gas continues to be generated after the transformer initially issues a light gas signal, the system cannot respond again. Furthermore, the light gas setting value is fixed, typically 200-300 ml, and does not consider the differences in fault development speed between transformers of different voltage levels. Ultra-high voltage transformers also face the risk of protection delay.

[0026] This solution is a transformer fast gas protection system, such as... Figure 2 The proposed approach involves installing two existing gas relays, namely gas relay A and gas relay B, in series on the connecting pipe between the transformer body and the oil conservator. Gas relay A is installed closer to the transformer body side, while gas relay B is installed closer to the oil conservator side to assist in detecting the accumulated gas level.

[0027] Gas relay A: Light gas A protection function is activated, heavy gas A protection function is activated; Gas relay B: Light gas B protection function is activated, heavy gas B protection function is deactivated. The baffle is removed to prevent impact on the heavy gas A protection function within gas relay A. A pressure surge sensor is connected in parallel to the light gas B contact to assist in confirming abnormalities on the oil conservator side. This solution completely preserves the existing mechanical structure and operating principle of the gas relays, without requiring redesign of the internal relay mechanism or changes to the installation method. Utilizing the existing light gas alarm contact and heavy gas trip contact of the relays, they are directly connected to the corresponding input ports of the non-electrical protection device via cables, achieving the principle of minimizing hardware modifications.

[0028] Among them, the heavy gas A is used independently. When a serious fault occurs inside the transformer, a large amount of gas is generated in a short time, accompanied by a violent surge of oil flow. The heavy gas A is triggered by detecting the oil flow speed, directly tripping the circuit breakers on each side of the main transformer to prevent equipment explosion or fire.

[0029] Among them, after the heavy gas baffle of gas relay B is removed, the serious fault on the oil tank side cannot be directly tripped. An independent mechanical pressure relief valve is installed at the oil tank outlet as a backup for heavy gas.

[0030] The transformer body has an oil temperature sensor that directly monitors the temperature. The sensor must be installed near the gas relay A at a distance of ≤1m from the relay to ensure that the monitored temperature is consistent with the gas diffusion environment.

[0031] like Figure 3 As shown, the light gas A contact is connected to the light gas input terminal of the non-electrical quantity protection device; the light gas B contact is connected to the spare input terminal 1 of the non-electrical quantity protection device; the closed and open contacts of the transformer power supply side circuit breaker are connected to the spare input terminals 2 and 3, respectively. Figure 3 As shown, the protection system includes an operation and anomaly judgment unit. When light gas A activates and the duration does not exceed the set value T1, if light gas B activates, a trip is triggered. If light gas A activates and T1 expires but light gas B does not activate, only an alarm signal is issued. The operation and anomaly judgment unit sets T1 and T2 time thresholds according to the transformer voltage level. T1 is the open window time after light gas A activates: 30 minutes for 1000kV and 60 minutes for 220kV; T2 is the accelerated trip time after the circuit breaker closes: 60 minutes for 1000kV and 90 minutes for 220kV. Furthermore, it can be upgraded through the non-electrical protection device program. When the light gas contact activates, a programmable time window is activated. If the heavy gas contact also activates during this period, it is determined to be a continuous fault and a trip is executed. The operating setting values ​​for light gas A and light gas B range from 260ml to 290ml, with a difference of 1-1.5ml. The setting value is lower for higher voltage levels, i.e., 260ml for 1000kV and 290ml for 220kV.

[0032] Oil temperature affects gas diffusion. At high temperatures, oil viscosity decreases, accelerating diffusion; at low temperatures, viscosity increases, delaying diffusion. Experimental data shows that when the oil temperature drops from 25°C to 0°C, the gas diffusion time is delayed by 40% to 60%. Therefore, an oil temperature compensation coefficient is introduced into the protection system. The oil temperature signal and gas signal are linked to dynamically calibrate the T1 and T2 timing thresholds. After calibration... Calibration coefficient With 25℃ as the critical point, when the oil temperature is below 25℃ = 1 + 0.015×(25 -θ), when the oil temperature is greater than 25℃ = 1 - 0.008×(θ-25). θ is the real-time oil temperature in °C. For a 1000kV transformer with θ=10℃: =1.225, ≈36.8 min, at θ=40℃ for a 220kV transformer: =0.88, ≈79.2min.

[0033] like Figure 3 As shown, the non-electrical quantity protection device is also connected to a partial discharge detection module. This module collects partial discharge signals inside the transformer using a high-frequency current transformer (HFCT), an ultra-high frequency (UHF) sensor, or an ultrasonic AE sensor, and sends the signals to the non-electrical quantity protection device via hard contacts. When the operation and anomaly judgment unit detects an abnormal partial discharge and the gas relay A operates, it shortens the T1 time window to accelerate the tripping judgment. If the partial discharge continues to increase but there is no gas operation, a partial discharge anomaly alarm is issued. If a sudden increase in partial discharge is detected after the circuit breaker is closed, the insulation degradation special criterion is triggered to prepare for tripping. When the local discharge amplitude exceeds a preset threshold, a suspected internal discharge alarm is activated even without gas operation.

[0034] As attached Figure 3 As shown, the system mainly consists of an input module, an output module, and an operation and anomaly judgment unit. The input module is responsible for real-time monitoring of the transformer's operating status and the gas relay's action signals. It includes: light gas A contact status acquisition, light gas B contact status acquisition, transformer power supply side circuit breaker closed position status acquisition, and transformer power supply side circuit breaker open position status acquisition. The light gas A contact status acquisition monitors the light gas contact status of gas relay A to determine the gas accumulation on the transformer body side. When the gas volume reaches the set value of 260ml~290ml, the contact closes, triggering an alarm or trip logic. The light gas B contact status acquisition monitors the light gas contact status of gas relay B to verify the persistence of the fault. If light gas A activates and light gas B also activates within the time window T1, it is determined to be a serious fault. The transformer power supply side circuit breaker closed position signal confirms that the transformer is in a energized operating state, serving as one of the activation conditions for the protection logic. The open position signal is used to determine whether the circuit breaker has been opened, preventing repeated tripping or malfunction. The input module transmits the above signals to the operation and anomaly judgment unit, which triggers the corresponding protection logic by combining the sequence of light gas A and B actions and the circuit breaker closed position with the light gas action state.

[0035] The switching module executes tripping or alarm operations based on logical judgment results. It is designed with a tripping circuit: a combined accelerated tripping circuit based on light gas A action and partial discharge anomaly, tripping circuit breaker 1 on each side of the main transformer; and a tripping circuit breaker 2 on each side of the main transformer after closing the circuit breaker and applying a sudden increase in partial discharge. High-voltage side tripping contacts 1 and 2 are dual-redundant tripping contacts to ensure reliable disconnection of the high-voltage side circuit breaker; a single tripping contact on the medium-voltage side is used to disconnect the medium-voltage side circuit breaker; and low-voltage side tripping contacts 1 and 2, for the dual-branch low-voltage side structure, control the two low-voltage circuit breakers respectively. Alarm signals are also designed: a warning mode for continuous partial discharge growth without gas action; light gas A and B protection action alarm signals indicating the action status of gas relays A and B respectively, prompting maintenance personnel to check the nature of the fault. The rapid light gas protection action alarm signal is the final tripping alarm after integrating the light gas A and B action logic. The device abnormality alarm signal monitors and protects against faults in the system itself. The output module directly drives the trip coil or signal relay through hard-contact output reed switch contacts, avoiding secondary circuit delays and ensuring fast and reliable operation.

[0036] The light gas action value collected by the input module and the trip delay of the output module are dynamically adjusted according to the voltage level to match the fault development speed. After the light gas A action, the timer starts in window T1. When the circuit breaker closing signal is combined with the light gas A action, the timer starts in window T2, triggering the post-closing position accelerated trip logic.

[0037] The operation and anomaly detection unit continuously monitors the input module signals by acquiring information from the input module with a 4ms sampling period. It performs comprehensive analysis and judgment, and controls the output module to activate the corresponding output contacts according to the analysis and judgment structure. The operation and anomaly detection unit has 16 independent output channels, supporting parallel triggering of tripping and alarms. The unit also features a human-machine interface, enabling functions such as display, setting, and information browsing and retrieval. Furthermore, it has a communication interface for information exchange with other intelligent devices.

[0038] Example 1: Hierarchical Timing Protection Mode

[0039] The fault mode gas diffusion path is from the transformer body to gas relay A to gas relay B, with dual threshold triggering of light gas A (260-290ml) and light gas B (260-280ml). Specifically... Figure 4 As shown, the procedure for rapid light gas protection mode 1 is as follows:

[0040] ① When an internal fault occurs in the transformer, the generated gas first diffuses to gas relay A. When the gas content reaches the tripping value of light gas relay A, light gas relay A trips; when the gas content continues to increase and reaches the tripping value of light gas relay B, light gas relay B trips.

[0041] ② The recommended setting range for the light gas relay A is 260ml to 290ml; determined according to the high-voltage side voltage level of the transformer, the recommended setting is 260ml for 1000kV transformers; 270ml for 800kV transformers; 280ml for 500kV transformers; and 290ml for 220kV transformers. The recommended setting range for the light gas relay B is also 260ml to 280ml; determined according to the high-voltage side voltage level of the transformer, the recommended setting is 260ml for 1000kV transformers; 270ml for 800kV transformers; 280ml for 500kV transformers; and 290ml for 220kV transformers. The increment between these levels is 1ml.

[0042] The reason for setting the transformer in the above manner is that the higher the voltage level of the transformer, the faster the internal fault develops. Therefore, the setting value and level difference should be smaller, which can improve the sensitivity of the non-electrical protection device for light gas protection.

[0043] ③ After the light gas relay A trips, a light gas A protection trip alarm signal is first issued, prompting the operating personnel to inspect the transformer according to the procedures. Then, the non-electrical quantity protection device determines whether the light gas A protection remains in the tripped state. If the light gas relay A contact has returned to its original position, the non-electrical quantity protection device resets and restarts the assessment. If the light gas relay A contact has not returned to its original position, the non-electrical quantity protection device starts timing and determines whether the duration of the light gas A protection trip reaches the set value T1. The T1 setting time is adjustable from 1 to 60 minutes. The recommended setting values ​​are: determined according to the high-voltage side voltage level of the transformer; 30 minutes for 1000kV transformers; 40 minutes for 800kV transformers; 50 minutes for 500kV transformers; and 60 minutes for 220kV transformers. The time increment is 1 minute.

[0044] The reason for setting the protection in the above manner is that the higher the voltage level of the transformer, the faster the internal fault develops. Therefore, if there is indeed an internal fault in a high-voltage transformer, the time it takes for it to develop into a serious fault will be short. In order to prevent the fast light gas protection from malfunctioning, the fast light gas opening time window is set from short to long according to the voltage level from high to low.

[0045] ④ When the non-electrical protection device determines that the duration of the light gas A protection action has not reached the set value T1, it further determines whether there is a light gas B protection action alarm signal. If there is, the fast light gas protection action logic is activated, on the one hand, the trip output relay is activated to trip the circuit breakers on each side of the main transformer, and at the same time, a fast light gas protection action alarm signal is sent; if not, it continues to determine whether light gas A is in the action holding state.

[0046] ⑤ When the non-electrical protection device determines that the duration of the light gas A protection action reaches the set value T1, it further determines whether the light gas B protection has been activated. If the light gas B protection has been activated, it sends a light gas B protection activation alarm signal to remind the operators that the internal fault of the main transformer is slowly developing and that it is necessary to shut down the power in time for inspection to prevent the internal fault of the transformer from suddenly developing into an explosive fault and causing personal injury during the inspection of the main transformer while it is energized. If the light gas B protection has not been activated, it continues to determine whether the light gas A protection remains in the activated state or in the activated holding state.

[0047] Example 2: Inrush Current Protection Mode

[0048] The circuit breaker's closed and open positions are invalid, triggering the closing timer T2. (See attached...) Figure 5 As shown, the second rapid light gas protection action mode is as follows:

[0049] ① When the non-electrical protection device determines that the closed position input of the high-voltage side circuit breaker of the transformer is connected and determines that the open position input of the high-voltage side circuit breaker of the transformer is disconnected, it confirms that the state of the high-voltage side circuit breaker of the transformer from the closed position to the open position is established, and then starts the closing position timing T2, and determines whether T2 has reached the set value.

[0050] If it is determined that T2 has not reached the set value, then it is determined whether the light gas relay A has operated. If, in step 1, it is determined that the light gas relay A has operated, then a light gas A protection operation alarm signal is first issued, and then the fast light gas protection operation logic is activated. On the one hand, the trip output relay is activated to trip the circuit breakers on all sides of the main transformer, and on the other hand, a fast light gas protection operation alarm signal is issued. If, in step 2, it is determined that the light gas relay A has not operated, then it is determined whether T2 has reached the set value. If it is determined whether T2 has reached the set value, then the entire non-electrical quantity protection device is reset.

[0051] The purpose of adopting the fast-acting light gas protection mode after closing is to prevent the transformer from developing into a serious fault due to internal deformation or insulation damage caused by the inrush current. By accelerating the tripping of the light gas A protection, the further development of the above-mentioned faults can be effectively avoided.

[0052] ② The recommended range of values ​​for the light gas relay A's operating setting is the same as that for fast light gas protection operating mode 1.

[0053] ③ The T2 setting time is adjustable from 1 to 90 minutes; the recommended setting values ​​are determined according to the voltage level of the high-voltage side of the transformer: 60 minutes for 1000kV transformers; 70 minutes for 800kV transformers; 80 minutes for 500kV transformers; and 90 minutes for 220kV transformers; with a time increment of 1 minute.

[0054] The reason for setting the transformer in the above manner is that the higher the voltage level of the transformer, the faster the internal fault develops, and the more likely it is to be cooled by forced oil circulation. Therefore, if there is indeed a fault inside the high voltage level transformer, its development speed is fast and the gas diffusion speed is even faster. Thus, the light gas A protection can reflect this type of fault in a short time. At the same time, timely stopping the accelerated tripping function of the light gas A protection can also avoid the occurrence of general light gas false tripping.

[0055] Example 3 Partial Discharge Protection Mode

[0056] Based on the aforementioned Embodiments 1 and 2, this embodiment introduces a partial discharge online monitoring module, forming a rapid light gas protection action mode 3 that integrates partial discharge detection, achieving highly sensitive, highly reliable identification and rapid response to early insulation faults inside the transformer. The specific implementation method is as follows:

[0057] ①System configuration: Install partial discharge sensors on the transformer body, including but not limited to high-frequency current transformers (HFCT), ultra-high frequency (UHF) sensors, or ultrasonic AE sensors. Their output signals are connected to the operation and abnormal judgment unit of the non-electrical protection device. At the same time, retain the original wiring structure of gas relay A near the transformer body and gas relay B near the oil tank. The light gas contact of gas relay A is connected to the light gas A input terminal, and the light gas contact of gas relay B is connected to the spare input terminal 1.

[0058] ② Partial discharge threshold setting: Set the partial discharge alarm and action threshold value according to the voltage level of the high-voltage side of the transformer. The following is recommended:

[0059] For 1000kV transformers: partial discharge ≥300pC is considered abnormal, ≥500pC triggers a combined tripping criterion; for 800kV transformers: ≥400pC is abnormal, ≥600pC triggers a combined tripping criterion; for 500kV transformers: ≥500pC is abnormal, ≥800pC triggers a combined tripping criterion; for 220kV transformers: ≥800pC is abnormal, ≥1000pC triggers a combined tripping criterion. These thresholds reflect the principle that the higher the voltage level, the stricter the insulation margin requirements and the lower the tolerable discharge.

[0060] ③ Protective Action Logic

[0061] Scenario 1: Light gas A-action plus partial discharge anomaly: combined accelerated tripping

[0062] When the non-electrical protection device detects the operation of the light gas relay A and receives a PD abnormal signal from the partial discharge monitoring module at the same time or during the T1 time period, and the discharge exceeds the operation threshold of the corresponding voltage level, the fast light gas protection operation logic is immediately activated. It does not need to wait for the light gas relay B to operate or for the T1 time period to complete, and directly trips the circuit breakers on each side of the main transformer, and issues a fast light gas plus partial discharge joint operation alarm signal.

[0063] This logic is applicable to sudden insulation degradation in high-voltage transformers during operation, such as inter-turn discharge or floating potential discharge. It can significantly shorten the time window from the initial appearance of the fault to its removal, preventing it from developing into breakdown or explosion.

[0064] Scenario 2: Only partial discharge continues to increase, without gas alarm mode.

[0065] If the partial discharge monitoring device detects a monotonically increasing discharge quantity for several consecutive power frequency cycles, such as an increase of ≥100pC every 10 minutes, but neither light gas A nor B activates, the non-electrical protection device will issue a partial discharge development alarm, prompting the operators to arrange live testing or plan a power outage for inspection; at the same time, the device will automatically record the discharge phase spectrum, pulse sequence and statistical characteristics for subsequent diagnostic analysis.

[0066] Scenario 3: Criteria for Judging the Sudden Increase in Closing Impact After Circuit Breaker Closure

[0067] When the device determines that the transformer is in the closed position (T2 timing period), if a sudden increase in partial discharge to above the operating threshold is detected within 5 minutes after closing, it is considered that the closing operation has induced an insulation defect. The device immediately blocks the reclosing and activates the trip output to trip the circuit breakers on all sides of the main transformer. This logic is particularly suitable for newly commissioned transformers, transformers that have undergone major repairs, or transformers that have been shut down for a long time and are now being energized. It can effectively prevent insulation weak points caused by mechanical stress or moisture from breaking down under operating overvoltage.

[0068] ④ Anti-interference and reliability measures: Partial discharge signal transmission adopts shielded cable and fiber optic isolation to avoid electromagnetic interference in the control circuit; the device has built-in digital filtering and pulse algorithm to distinguish between real discharge and external noise such as switch operation and radio interference; all partial discharge related alarms and action events are timestamped and can be uploaded to the substation monitoring system through the communication interface.

[0069] This embodiment is particularly suitable for important main transformers with voltage levels of 500kV and above, and can significantly improve the level of safe operation of the power grid.

[0070] The above is a detailed description of the present invention in conjunction with specific embodiments, and it should not be construed that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, any equivalent substitutions or obvious modifications made without departing from the concept of the present invention, and which have the same performance or use, should be considered to fall within the patent protection scope defined by the submitted claims.

Claims

1. A fast gas protection system for a transformer, the protection system comprising a gas relay and a connecting pipe, the connecting pipe being designed between the transformer body and the oil conservator, and including a gas relay A and a gas relay B, characterized in that: Gas relay A, located near the transformer body, activates both light and heavy gas. Gas relay B, located near the oil conservator, activates only light gas and removes the heavy gas baffle. The timing of gas diffusion is detected by adjusting the physical position difference. The light gas A contact of gas relay A is connected to the light gas input terminal of the non-electrical quantity protection device, and the light gas B contact of gas relay B is connected to the spare input terminal 1 of the non-electrical quantity protection device. The closed and open contacts of the power supply side circuit breaker of the transformer body are connected to the spare input terminals 2 and 3, respectively. An oil temperature sensor is installed near gas relay A on the transformer body.

2. The transformer fast gas protection system according to claim 1, characterized in that: The protection system includes an operation and anomaly judgment unit. This unit sets time thresholds T1 and T2 based on the transformer voltage level. T1 is the open window time after the light gas A action, and T2 is the accelerated tripping time of the circuit breaker after closing. When light gas A acts and its duration does not exceed the set value T1, if light gas B acts, a trip is triggered. When the duration of light gas A's action reaches T1, if light gas B does not act, only an alarm signal is issued. The protection system introduces an oil temperature compensation coefficient to dynamically calibrate the timing thresholds T1 and T2 by linking the oil temperature signal with the gas signal.

3. The transformer fast gas protection system according to claim 1, characterized in that: The protection system includes a partial discharge detection module, which collects partial discharge signals inside the transformer and sends the signals to the non-electrical protection device in the form of hard contacts.

4. The transformer fast gas protection system according to claim 1, characterized in that: The protection system includes circuit breaker status judgment. When the high-voltage side circuit breaker of the transformer changes from closed to open, the tripping is directly triggered if the light gas A operates within time T2.

5. A transformer fast gas protection system according to claim 1, characterized in that: The setpoints for the operation of light gas A and light gas B range from 260ml to 290ml, with a increment of 1-1.5ml, and the setpoints decrease as the voltage level increases.

6. A transformer fast gas protection system according to claim 1, characterized in that: The protection system includes an input module and an output module. The input module and the output module work together through an operation and anomaly judgment unit to achieve rapid response and graded tripping of light gas protection.

7. A transformer fast gas protection system according to claim 6, characterized in that: The input module includes the acquisition of the status of light gas A contact, the status of light gas B contact, the closed position status of the transformer power supply side circuit breaker, and the open position status of the transformer power supply side circuit breaker. The input module transmits the above signals to the operation and anomaly judgment unit, and triggers the protection logic through timing analysis and status combination.

8. A transformer fast gas protection system according to claim 6, characterized in that: The aforementioned output module performs tripping or alarm operations based on the logical judgment result, and directly drives the tripping or signal relay with hard contact output.

9. A transformer fast gas protection system according to claim 6, characterized in that: The light gas action value collected by the input module and the tripping delay of the output module are dynamically adjusted according to the voltage level.

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