How to deal with substation bus loss of voltage 30

The loss of voltage in the substation bus should be faulty, and it should not be closed again at will until the fault is found and eliminated. To find faults, disconnect the multiple loads and then close the power-side circuit breaker. If the circuit breaker on the power side can be closed smoothly, it means that there is no problem with the busbar, and then the load is switched off and closed one by one.

Disconnect the faulty load again, and re-send power to each load one by one, so that the faulty load line can finally be found out and the power supply of the normal load line can be restored.

First of all, it should be judged according to the action of various signals and protection devices, if it is a bus fault that causes the bus differential protection action, it is necessary to open the switches of the faulty bus (check the actual position of the jump switch) and the isolation switch, and carry out the power transmission operation according to the regulations after checking and processing to meet the power transmission conditions. If the bus voltage loss is caused by the failure of the protection device to operate correctly due to external faults or other reasons, the circuit breaker and isolation switch of the faulty power supply (line) need to be opened, check that all circuit breakers of the bus are in the disconnected position, and then carry out the bus power transmission operation according to the regulations. Finally, the fault line is handled.

Handling methods: 1) After the bus of the terminal substation powered by a single power supply is pressurized, the personnel on duty should immediately check and report to the dispatch, if the cause of power loss is not caused by the bus or main transformer failure of the institute, the original state of the equipment of the institute can be kept unchanged; If the main transformer fault trips over the level, the switches on each side of the main transformer should be pulled open for inspection and processing; After the switch on the medium and low voltage side of the main transformer trips and causes power loss on the bus, the personnel on duty should carry out a detailed inspection of the bus and the electrical equipment at each outgoing interval, and report to the dispatch, and pull all the switches on the bus; If it is not the bus fault or the main transformer protection is malfunctioning, it is generally caused by the line fault, switch or protection refusal, and the power transmission of the power outage bus can be resumed after the refusal switch is found to be disconnected and the knife switch is opened.

2) The multi-power supply bus loses power. Confirm that the cause of the bus pressure is not caused by the bus failure of the institute, and the single bus should retain a power switch, and all other open and answer points should be opened. The double bus should first pull the bus tie switch, and then keep only one main power switch on each group of bus, and all the other switches are opened.

Check that there is no rejection switch, if there is, the switch should be disconnected and the knife switch should be pulled open, and report to the dispatch.

3) After the power loss of the power plant bus, the switch that may come to the power should be pulled open immediately, when conditions permit, the use of the unit of the plant to the bus zero booster, after the success of the power plant to restore the power plant and the system at the same time in parallel, if the power failure bus test power, should be used as far as possible with external power supply.

Reason 1: When there is no reactor for a short circuit on the line side close to the circuit breaker, and the protection device or circuit breaker fails to operate, so that the short-circuit current cannot be cut off. 2、.The bus voltage disappears when the power supply is interrupted and the bus is short-circuited or due to a short circuit on the leads between the bus circuit breakers.

The disappearance of the bus voltage is the most serious accident in the system, and it should be dealt with as quickly as possible to restore the voltage stool.

1) Flashover caused by the surface contamination of the bus insulated and closed spikes and circuit breaker bushings. (2) The voltage transformer installed on the bus and the current transformer between the bus and the circuit breaker fail. (3) The support insulator of the circuit breaker or disconnector is damaged during the reverse operation.

4) Due to the misoperation of the sedan by the personnel running the mountain shed, such as the arc short circuit caused by the load broach switch.

Questions. <>

Is it the undervoltage fault of the bus of the inverter air compressor?

1 The first is the influence from the incoming line voltage. If the quality of the power grid is not good and there is a momentary voltage drop, it will inevitably cause the bus voltage to be too low. In the process of starting large equipment, it is inevitable that the grid voltage will decrease.

Occasional transient voltage dips are difficult to capture, which adds to the difficulty of diagnosing faults. If it can be confirmed that there is a problem with the quality of the power grid (such as a short-term voltage drop caused by the start of a large motor), and it is difficult to change such a power environment, then the "automatic restart" function of the inverter can be enabled, and the inverter will be stopped under voltage when the voltage drops; When the grid is restored, the inverter automatically starts again. It is also a good option to add a voltage regulator to the inlet.

However, it is necessary to use the inverter for the exclusive use of the mountain slag town. During lightning, it may also have an instantaneous impact on the grid voltage, and it may also cause the undervoltage fault of the inverter. However, thunder is also a very accidental event of Liang Pi, and it will not always bother the operation of the inverter.

However, for safety reasons, the factory should have lightning protection measures. 2 The second is the influence from the output side, i.e. the inverter side. As the motor accelerates, the motor obtains electrical energy from the inverter and converts it into kinetic energy.

If the acceleration time is short and the acceleration is high, then the bus voltage will be quickly pulled down, resulting in an undervoltage.

2 The second is the influence from the output end, that is, the inverse guess of the ignition converter side. When the motor accelerates, the motor obtains early orange electrical energy from the inverter and converts it into kinetic energy. If the acceleration time is short and the acceleration is high, the bus voltage will be quickly pulled down, resulting in an undervoltage fault.

In response to this situation, the treatment methods are: · Extended acceleration time· If the PID technology controller is used, pay attention to reduce the system response, subtract p plus i, and extend the filtering time.

Questions. <>

What is the maximum amount of time that can <> prorate?

The change should be within 20%, otherwise it is easy to damage the components.

Questions. According to the above fan frequency conversion and main frequency conversion maximum can be extended?

About 10 points.

Regardless of whether the two sections of the bus are operated separately or in parallel, the protection of the bus and the voltage of the metering device cannot be lost. The pressure-transformer secondary parallel device is mainly used for the pressure-transformer secondary parallel of two sections of bus (single bus segment or double bus). When a section of bus pressure transformer exits operation, the two sections of bus must be run in parallel, and the pressure transformer circuit must also be paralleled to avoid the loss of pressure of the protection and metering device, so that the protection or automatic device can be misoperated or refused.

Therefore, it is required that the secondary voltage circuits of the protection and automatic devices be switched together with the main wiring.

If the pressure transformer is grounded or short-circuited, pulling the pressure transformer blade directly will pull the arc, causing the fault to expand or other faults, and it can be directly changed and repaired when there is no fault.

The bus transformer is usually used for the metering, protection, and installation of all three phases of the equipment connected to this bus. Precision.

High and reliable

The line transformer only measures and protects the line where it is located, and usually only installs two or one phase.

If the transformer is grounded or short-circuited, pulling the transformer blade directly will pull the arc, causing fault expansion or other faults.

There are three types of bus loss phenomenon:

1) The voltmeter on this bus.

The indication is zero; 2) The load crack of each outlet line and transformer on the bus disappears, and the imitation current of the load head is zero;

3) The high-fiber electricity used on the bus loses power.