Transformer relay protection - Solutions - Huaqiang Electronic Network

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

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The relay protection of the transformer is to use the sudden change of current, voltage, oil temperature, etc. when the fault occurs inside and outside the transformer. Through these sudden changes, the fault nature and range of the transformer are found and judged, and then the corresponding reaction and treatment are made.
After the post-action check and processing relay protection action, if it is confirmed that it is a quick-break protection action, the signal sound can be temporarily released. If there is gas protection, first check whether the gas protection is active. If it is not working, the fault point is outside the transformer. Check the transformer and the high-voltage circuit breaker to supply the transformer to the transformer to see if there is any phase-to-phase short-circuit fault between the cable and the bus. In addition, it is also important to check whether the transformer high-voltage lead has obvious fault points and other obvious abnormal phenomena, such as transformer injection, fire, and excessive temperature rise.
If it is found to be a gas action, it can be basically judged that the fault is inside the transformer. First, when the transformer windings are partially short-circuited between the turns, the core insulation is poor, and the transformer is seriously oily, the oil level is lowered, and the light gas will act. When a serious fault occurs inside the transformer, such as a winding fault, the phase-to-phase short circuit is caused. The fault current causes the transformer to generate a strong airflow and oil flow, impacting the heavy gas barrier, causing heavy gas action, the circuit breaker to trip and signal. Second, if there is no obvious abnormality in the transformer at that time, the gas of the transformer can be collected to further analyze and determine the nature of the fault. If the collected gas is colorless, odorless, and non-flammable, the reason for the action of the gas relay is caused by the air discharged from the oil; if the collected gas is yellow, it is not easy to burn, indicating that the transformer is partially broken; if the gas is If the light yellow color has a strong odor and is flammable, it is a fault of the insulating paper or paperboard; when the gas is gray or black, it is a fault of the insulating oil. For an outdoor transformer, the gas valve of the gas relay can be turned on to ignite the gas discharged from the bleed valve, and if the gas is flammable, it will burn and emit a bright flame. It should be noted that when the oil begins to overflow from the outside of the bleed valve, the bleed valve should be quickly closed; for indoor transformers, ignition test should be prohibited indoors; the color of the gas should be judged to be rapid, otherwise the color of the gas will disappear quickly; The transformer gas should be stopped after power failure. Third, if the gas protection action has not yet been identified, in order to further confirm whether the transformer is in good condition, the transformer oil sample can be taken out for a simplified test to see if there is a decrease in withstand voltage and a drop in oil flash point. If there is still no problem, the gas protection secondary circuit should be further checked to see if the gas protection malfunctions to verify the reliability of the relay protection. When the transformer is moving with heavy gas, the circuit breaker is tripped. If the fault is not handled, it does not prove that the transformer is fault-free, and the power cannot be re-closed.
If it is found that it is a differential protection action, it is necessary to judge the cause of the action. It is necessary to accurately determine the cause of the transformer casing, etc., or the cause of the internal fault of the transformer.
Matters needing attention Relay protection device should use high quality relays and protection components, the contact points of components should be as small as possible; the installation quality should be qualified, the protection disk and control panel should be firm and reliable, avoid being installed in places with vibration, the quality of the terminal should be qualified. The wiring should be good. Before the relay is put into operation, the duty personnel and operators should clearly interpret the working principle of the protection device.
During the operation of the relay protection device, it is necessary to strengthen the monitoring and immediately report to the person in charge of the emergency; the relay protection device in operation shall not arbitrarily remove the protection operation, or arbitrarily change the setting value, unless the dispatching department or the supervisor agrees. The secondary line; the input or exit of the operating relay protection device by the operating personnel must be approved by the dispatcher or the person in charge of the supervisor and recorded in the duty record book. If it is necessary to change the relay protection setting value or the secondary circuit wiring, it must be approved by the relay protection professional.
All work on the secondary circuit shall comply with the relevant provisions of the Electrical Safety Work Regulations.
When the duty officer is turned over*, when the relay protection circuit is involved, the relay protection shall be treated according to the performance of the relay protection device and the operating regulations, but it is important to remember that the duty guards only work on the relay protection device. The protective platen is turned on or off; the transfer switch is switched; the fuse of the fuse is loaded and unloaded.
After the relay protection action circuit breaker trips, do not return the signal to the card, but check the protection action and find out the cause. All the cards will be returned before the fault recovery and power transmission.