CN104242289B - A kind of switching overvoltage restraining device - Google Patents

Abstract

An operating overvoltage suppression device, the device includes a main switch circuit, a closing damping circuit and a voltage equalizing circuit, the main switching circuit is connected in parallel with the closing damping circuit and the voltage equalizing circuit, and the device is also connected in parallel with a protection circuit for overvoltage protection, Set the sampling unit and the transmission unit for sampling and data transmission, and the operation overvoltage suppression device adopts a multi-closing switch structure, which can reliably prevent the heating effect caused by a single closing switch, and adopts a parallel protection device to prevent damage to the device caused by overvoltage , and use the monitoring device to monitor the suppression device to confirm the working status of the suppression device, which has the reliability and stability of long-term operation.

Description

An operating overvoltage suppression device

technical field

The invention relates to an overvoltage suppression device for an ultra-high voltage system, in particular to an operation overvoltage suppressor.

Background technique

In the ultra-high voltage system, the overvoltage caused by the internal reasons of the power system is called internal overvoltage. This is because there are electric field inertial elements (capacitors) and magnetic field inertial elements (inductance) in the power system. When the circuit breaker is operated (including normal operation and accident operation), the power system will transition from one stable state to another. In a stable state, the electromagnetic field energy in the system components needs to be redistributed. This is an oscillation process. When the system parameters are improperly matched, a high overvoltage will appear. Internal overvoltage includes two types, transient overvoltage and operating overvoltage. Since most high-voltage transmission lines have the characteristics of long-distance and large-capacity transmission of electric energy, the overvoltage of closing and opening operations will bring great harm to the safety of line equipment and systems. The hazard of operating overvoltage is mainly to damage the insulation of equipment. For systems with lower voltage levels, operating overvoltage is not a factor that determines the insulation level, but with the increase of system voltage, the problem of operating overvoltage is very prominent. If Failure to take voltage limiting measures will lead to a rapid increase in equipment insulation costs.

The patent document CNCN200910168255 adopts an opening and closing system, which adopts a parallel structure when setting the circuit breaker, that is, adopts a structure in which the resistance switch is connected in series with the closing resistance and then connected in parallel with the main switch, and the closing switch First close, connect the closing resistance to the circuit in series, then close the main switch, and short the closing resistance, so that during the closing process, the closing resistance of the closing circuit can dampen the oscillation, reducing the The amplitude of the closing operation overvoltage is determined.

However, when the vibration generated in the transmission line is large, using a closing resistor and a circuit breaker is likely to cause the resistance to heat too fast when the circuit breaker is closing, resulting in damage to the resistance, and the main switch cannot be activated in the closing circuit in time. If it is closed after closing, it is easy to cause the resistor to overheat and explode. Therefore, the opening and closing system still has defects, which affect the stability and reliability of the EHV transmission system in long-term power transmission operation.

Contents of the invention

Based on the problems existing in the prior art, the present invention provides an operating overvoltage suppression device, which includes a main switch circuit, a closing damping circuit and a voltage equalizing circuit, and the main switching circuit is connected in parallel with the closing damping circuit and the voltage equalizing circuit , wherein the main switch circuit has a main circuit breaker, the closing damping circuit has a closing resistor 1, a closing switch 1, a closing resistor 2 and a closing switch 2 in series in sequence, and the voltage equalizing circuit adopts a series voltage equalizing capacitor 1 and an equalizing capacitor Pressure capacitor two, or use RC voltage equalizing circuit 1 and RC voltage equalizing circuit 2 in series, the junction of voltage equalizing capacitor 1 and voltage equalizing capacitor 2 in series, or connect RC voltage equalizing circuit 1 and RC voltage equalizing circuit 2 in series The connecting point is connected with the connecting point between the closing switch one and the closing resistor two.

The closing resistor is mainly used to weaken the electromagnetic oscillation and limit the overvoltage by converting part of the electric energy in the grid into heat energy. During the closing or reclosing process of the circuit breaker, before the main contact is closed, a closing resistor is connected in series in the load circuit for a short time, thereby damping the transient overvoltage. The optimal control of overvoltage requires the correct selection of the closing resistor according to the impedance level of the power supply, the length of the line and the parameters. When the closing resistor is turned on, the current flowing through it is very small and the duration is very short. When the circuit breaker is closed, the resistance is closed ahead of the main break. After the main break is closed, the resistance break is short-circuited by the main break. When the circuit breaker is opened, the resistance break should be opened before the main break to ensure the current and short circuit of the main break. current. A voltage equalizing capacitor or an RC equalizing circuit are respectively connected in parallel in the fracture to prevent the closing voltage of the two closing switches from being out of sync, resulting in different closing voltages, resulting in contact welding or arcing, and the closing resistance is used to limit For closing overvoltage, the two closing switches are connected in series with the closing resistor; when closing, the two closing switches require the main circuit breaker to be closed first, so that the closing resistor will be put into operation first, and when the main circuit breaker is closed , the closing switch will be short-circuited by the main breaker and out of operation.

The operation overvoltage suppression device is also connected in parallel with a protection circuit. The protection circuit uses a metal oxide voltage limiter, such as a lightning arrester. Release, the protection device closes and opens smoothly and can resist the influence of a certain overvoltage.

In order to facilitate the substation personnel or the remote control center to know whether each device is in a normal working state, that is, whether the voltage limiter is turned on or damaged, whether the switch is closed normally, whether the resistor is overheated and damaged, etc., it is necessary to set a sampling device. The sampling device of the present invention It includes a voltage sampling unit, a current sampling unit, a temperature sampling unit and a video monitoring unit. The voltage sampling unit includes collecting the voltage of the main circuit breaker, closing switch, closing resistor and voltage limiter. The current sampling unit collects the closing circuit and the main breaking circuit. The current of the circuit, the temperature sampling unit collects the temperature of the resistor, the video monitoring unit can only be set in the important suppression device, and the video monitoring is carried out to confirm the working status of the device, and the sampling device samples the data through the A/D conversion unit and processing Connected to the controller, the processor processes the data and stamps the time stamp. After the data is electro-optical converted by the light emitting unit, it is transmitted to the substation or remote control center through the optical fiber. The substation or remote control center receives the data through the light receiving unit and analyzes the data. In order to realize the monitoring and operation of the working condition of the overvoltage suppression device.

The operating overvoltage suppression device of the present invention also adopts a synchronous closing device, which calculates the delay of the control command, and then sequentially controls the three-phase closing or opening of the circuit breaker at the desired theoretical voltage or current phase, and the synchronous opening and closing The device collects one-phase voltage of the busbar or line as the reference voltage. Under the inductive load, the vector relationship between voltage and current can be regarded as the voltage leading the current by 90 degrees, that is, the current crosses zero when the voltage is at its maximum value. The system sends a closing command to the device, and the device uses the time point of the next voltage zero-crossing point of the reference voltage as the triggering timing of the closing pulse, and calculates the delay time Td for issuing the closing command of the circuit breaker according to the inherent operating time of the circuit breaker , so that the current of the circuit breaker can be controlled from the appropriate time. The start time of the current between the contacts is earlier than the actual contact time of the contacts because the circuit breaker contacts have pre-arcing conditions, so the actual contact time of the contacts must be Later than the peak time of the system voltage (that is, the current zero point), the time difference is the pre-arcing time. The pre-arcing time of the three phases can be adjusted and set separately to realize the synchronous closing of the circuit breaker.

The operating overvoltage suppression device of the present invention adopts a multi-closing switch structure, which can reliably prevent the heating effect brought by a single closing switch, and adopts a parallel connection protection device to prevent overvoltage from causing damage to the device, and uses a monitoring device to monitor the suppression device. Monitoring to confirm the working status of the suppression device has long-term reliability and stability.

Description of drawings

Fig. 1 is an operating overvoltage suppression device in the prior art.

Fig. 2 is the operating overvoltage suppression device provided by the present invention.

detailed description

The operating overvoltage suppression device includes a main switch circuit, a closing damping circuit and a voltage equalizing circuit. The main switching circuit is connected in parallel with the closing damping circuit and the voltage equalizing circuit. The closing resistor 1, closing switch 1, closing resistor 2 and closing switch 2, the voltage equalizing circuit adopts the voltage equalizing capacitor 1 and the voltage equalizing capacitor 2 in series, or adopts the RC voltage equalizing circuit 1 and RC equalizing circuit in series Circuit 2, the connection between the first voltage equalizing capacitor and the second equalizing capacitor in series, or the connection between the first RC voltage equalizing circuit and the second RC voltage equalizing circuit connected in series with the connection between the first closing switch and the second closing resistor .

The closing resistor is mainly used to weaken the electromagnetic oscillation and limit the overvoltage by converting part of the electric energy in the grid into heat energy. During the closing or reclosing process of the circuit breaker, before the main contact is closed, a closing resistor is connected in series in the load circuit for a short time, thereby damping the transient overvoltage. The optimal control of overvoltage requires the correct selection of the closing resistor according to the impedance level of the power supply, the length of the line and the parameters. When the closing resistor is turned on, the current flowing through it is very small and the duration is very short. When the circuit breaker is closed, the resistance is closed ahead of the main break. After the main break is closed, the resistance break is short-circuited by the main break. When the circuit breaker is opened, the resistance break should be opened before the main break to ensure the current and short circuit of the main break. current. A voltage equalizing capacitor or an RC equalizing circuit are respectively connected in parallel in the fracture to prevent the closing voltage of the two closing switches from being out of sync, resulting in different closing voltages, resulting in contact welding or arcing, and the closing resistance is used to limit For closing overvoltage, the two closing switches are connected in series with the closing resistor; when closing, the two closing switches require the main circuit breaker to be closed first, so that the closing resistor will be put into operation first, and when the main circuit breaker is closed , the closing switch will be short-circuited by the main breaker and out of operation.

The operation overvoltage suppression device is also connected in parallel with a protection circuit. The protection circuit uses a metal oxide voltage limiter, such as a lightning arrester. Release, the protection device closes and opens smoothly and can resist the influence of a certain overvoltage.

In order to facilitate the substation personnel or the remote control center to know whether each device is in a normal working state, that is, whether the voltage limiter is turned on or damaged, whether the switch is closed normally, whether the resistor is overheated and damaged, etc., it is necessary to set a sampling device. The sampling device of the present invention It includes a voltage sampling unit, a current sampling unit, a temperature sampling unit and a video monitoring unit. The voltage sampling unit includes collecting the voltage of the main circuit breaker, closing switch, closing resistor and voltage limiter. The current sampling unit collects the closing circuit and the main breaking circuit. The current of the circuit, the temperature sampling unit collects the temperature of the resistor, the video monitoring unit can only be set in the important suppression device, and the video monitoring is carried out to confirm the working status of the device, and the sampling device samples the data through the A/D conversion unit and processing Connected to the controller, the processor processes the data and marks the time stamp. After the data is electro-optical converted by the light emitting unit, it is transmitted to the substation or remote control center through optical fiber. The substation or remote control center receives the data and analyzes the data to realize the monitoring operation. The working condition of the overvoltage suppression device.

The circuit breaker of the present invention also adopts a synchronous closing device, which calculates the delay of the control command, and then sequentially controls the three-phase closing or breaking of the circuit breaker at the desired theoretical voltage or current phase, and the synchronous opening and closing device collects the bus Or the one-phase voltage of the line is used as the reference voltage. Under the inductive load, the vector relationship between the voltage and the current can be considered as the voltage leading the current by 90 degrees, that is, the current crosses zero when the voltage is at the maximum value. The system sends a closing command to the device, and the device uses the time point of the next voltage zero-crossing point of the reference voltage as the triggering timing of the closing pulse, and calculates the delay time Td for issuing the closing command of the circuit breaker according to the inherent operating time of the circuit breaker , so that the current of the circuit breaker can be controlled from the appropriate time. The start time of the current between the contacts is earlier than the actual contact time of the contacts because the circuit breaker contacts have pre-arcing conditions, so the actual contact time of the contacts must be Later than the peak time of the system voltage (that is, the current zero point), the time difference is the pre-arcing time. The pre-arcing time of the three phases can be adjusted and set separately.

The operating overvoltage suppression device of the present invention adopts a multi-closing switch structure, which can reliably prevent the heating effect brought by a single closing switch, and adopts a parallel connection protection device to prevent overvoltage from causing damage to the device, and uses a monitoring device to monitor the suppression device. Monitoring to confirm the working status of the suppression device has long-term reliability and stability.

Claims (1)

1. a kind of switching overvoltage restraining device, it is characterised in that switching overvoltage restraining device includes main switch loop, closes a floodgate Damping circuit and road is pushed back, main switch loop and combined floodgate damping circuit, push back road and be connected in parallel；Main switch loop has There is main circuit breaker, combined floodgate damping circuit the switching-on resistance one being sequentially connected in series, closing switch one, switching-on resistance two and combined floodgate to open Two are closed, equalizing capacitance one and equalizing capacitance two of the road using series connection is pushed back, or it is equal using the RC equalizer circuits one and RC of series connection Volt circuit two, the equalizing capacitance one of series connection and the junction of equalizing capacitance two, or the RC equalizer circuits one and the equal piezoelectricity of RC connected The junction on road two is connected with closing switch one with the junction of switching-on resistance two, and the switching overvoltage restraining device is also simultaneously Protection circuit is associated with, protection circuit uses metal oxide pressure-limiting device, sampling apparatus is set, sampling apparatus includes voltage sample list Unit, current sampling unit, temperature sampling unit and video monitor unit, voltage sampling unit include collection main circuit breaker, close The electricity in the voltage of lock switch, switching-on resistance and voltage limiter, current sampling unit collection closing circuit and main circuit breaker loop Stream, temperature sampling unit gathers the temperature of resistance, and video monitor unit carries out video monitoring to confirm the working condition of device, adopts Sampling device will be connected by A/D converting units after data sampling with processor, and processor stamps markers after processing data After data are carried out electro-optic conversion by Optical Transmit Unit, by Optical Fiber Transmission to transformer station or remote control center, transformer station Or remote control center receives data and data is analyzed to realize policer operation Overvoltage suppressing by light receiving unit The working condition of device, the phase voltage for gathering bus or circuit using same period switching off/on device as the reference voltage, sends conjunction Lock order to device, using next voltage over zero time point of reference voltage as the triggering timing moment of closing pulse, root According to the breaker intrinsic operating time, calculate breaker closing order and send time delay Td, to realize the same of breaker Phase closes a floodgate.