CN207268771U - A single-phase circuit breaker opening and re-breakdown simulation experiment device - Google Patents

Abstract

A kind of single-phase circuit breaker separating brake repeated breakdown analogue experiment installation, composition include Triggered Vacuum Switch, pulse transformer, IGBT, voltage sensor and MCU, and the Triggered Vacuum Switch is attempted by breaker；The primary coil of the pulse transformer is connected by IGBT with DC power supply, and the output signal of secondary coil connects the trigger electrode of Triggered Vacuum Switch；The grid of the IGBT connects the output port of MCU；The current sensor is switched off device egress line and passes through, the input port of output termination MCU.The utility model is by the conducting of Triggered Vacuum Switch come the separating brake repeated breakdown of mimic-disconnecting switch, Triggered Vacuum Switch not only quick action, and the electric current flowed through is sufficiently large, responsiveness and discharge capacity can meet requirement of experiment, can provide technical support for the experimental verification of arrester various characteristics.In addition, the utility model also has simple in structure, high reliability.

Description

A single-phase circuit breaker opening and re-breakdown simulation experiment device

technical field

The utility model relates to an experimental device for simulating the opening and re-breaking of a single-phase vacuum circuit breaker, which belongs to the technical field of testing.

Background technique

When the vacuum circuit breaker breaks the reactive power compensation capacitor bank, it is prone to heavy breakdown. The overvoltage amplitude caused by the switch heavy breakdown or multiple heavy breakdowns is high, which will damage the capacitor and affect the life of the capacitor. For this reason, the surge arrester is generally connected between the power supply side of the capacitor and the ground to limit the magnitude of the overvoltage on the power supply side of the capacitor. In order to protect capacitors more effectively and select surge arresters reasonably and economically, it is necessary to do circuit breaker opening and re-breakdown tests to test various characteristics of arresters and determine the current capacity and energy absorption of arresters. However, the restrike of the circuit breaker is an uncontrollable phenomenon that happens occasionally, so it is of great practical significance to study the simulation experiment device of the breaker's opening and restrike.

At present, the devices that can be used for circuit breaker opening and re-strike simulation experiments are mainly divided into two categories, one is mechanical devices, and the other is power electronic devices. Mechanical devices can meet the requirements of voltage and current, but the action speed is slow, so it is difficult to meet the experimental requirements. The power electronic device operates fast, but its withstand voltage is small and its internal resistance is large, so the current passing through it cannot be too large. Therefore, it has become a research topic for relevant technical personnel to design a circuit breaker opening and re-strike simulation experiment device with large current and fast action speed.

Utility model content

The purpose of this utility model is to provide a single-phase circuit breaker opening re-breakdown simulation experiment device for the disadvantages of the prior art, and provide technical support for the experimental verification of various characteristics of the arrester.

Problem described in the utility model is solved with following technical scheme:

A single-phase circuit breaker opening and re-breakdown simulation experiment device, the composition includes a vacuum trigger switch, a pulse transformer, an IGBT, a current sensor and an MCU, and the vacuum trigger switch is connected to the circuit breaker; the original pulse transformer The side coil is connected to the DC power supply through the IGBT, and the signal output by the secondary coil is connected to the trigger pole of the vacuum trigger switch; the gate of the IGBT is connected to the output port of the MCU; the current sensor is passed through by the outlet line of the circuit breaker, and the output terminal is connected to the The input port of the MCU.

In the above single-phase circuit breaker opening and re-breakdown simulation experiment device, the current sensor adopts a Rogowski coil.

The utility model simulates the opening and re-breakdown of the circuit breaker through the conduction of the vacuum trigger switch. The vacuum trigger switch not only has a fast action speed (the action time can reach the microsecond level), but also has a large enough current (can reach dozens of kA, which is dozens of times that of power electronic devices), the action speed and flow capacity can meet the experimental requirements, and can provide technical support for the experimental verification of various characteristics of the arrester. In addition, the utility model also has the advantages of simple structure and high reliability.

Description of drawings

Fig. 1 is the electrical schematic diagram of the utility model.

The labels in the figure are respectively represented as: QF, circuit breaker; MCU, microcontroller; T, pulse transformer; TVS, vacuum trigger switch; IGBT, insulated gate bipolar transistor; CT, current sensor.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail.

Referring to Fig. 1, the utility model includes MCU, pulse transformer T, vacuum trigger switch TVS, IGBT and current sensor CT.

Connect the vacuum trigger switch TVS to both ends of the circuit breaker QF in parallel. After the circuit breaker QF is disconnected, use the pulse generated by the pulse transformer T to trigger the vacuum trigger switch TVS to make the circuit re-conduct, so as to simulate the opening of the circuit breaker QF. Put on. The vacuum trigger switch TVS has a fast action speed, and the action time can reach the microsecond level, which is difficult for mechanical devices. The current flowing through the vacuum trigger switch TVS can reach tens of kA, which is dozens of times the current allowed to flow through power electronic devices. Using TVS to simulate heavy breakdown can meet the experimental requirements in both action speed and flow capacity.

The current sensor CT uses a Rogowski coil to detect the change of the current waveform in the test circuit.

The MCU is equipped with an AD conversion module and a single-chip microcomputer. The AD conversion module can convert the analog signal from the current sensor CT into a digital signal, and then transmit the digital signal to the single-chip microcomputer. The single-chip microcomputer compares the digital signal from the AD conversion module with the set value in real time, and sends a control signal to the IGBT when the digital signal reaches the set value.

The IGBT, 100V DC power supply and the primary coil of the pulse transformer T form a loop. When the MCU detects that the circuit breaker QF is disconnected, it sends a trigger signal to the IGBT with a delay of 10ms (at this time, the voltage at both ends of the circuit breaker contacts reaches 2U _m ), The IGBT is turned on, the whole circuit is closed and turned on, and the high-voltage side of the pulse transformer (secondary coil) generates a high-voltage pulse, which triggers the TVS to turn on, so as to achieve the purpose of simulating the re-breakdown of the circuit breaker.

During the test, the current sensor CT converts the loop current signal into a 0-5V voltage signal and transmits it to the MCU. The AD in the MCU converts the 0-5V analog voltage signal into a 0-255 digital voltage signal and transmits it to the microcontroller. The current signal in the loop is a constantly changing sinusoidal signal, and the microcontroller will also receive a constantly changing digital signal. When the circuit breaker receives the breaking signal, the circuit breaker is disconnected, the current in the circuit becomes zero, and the output voltage of the current sensor (CT) becomes zero. When the single-chip microcomputer receives the circuit current signal and returns to zero, the delay is about 10ms, and a trigger is issued. IGBT turn-on signal. The primary side circuit of the pulse transformer is turned on, and the secondary side generates a high-voltage pulse, which triggers the TVS to be turned on, so that the test circuit is turned on again.

After the MCU is turned on, the single-chip microcomputer will continuously receive 0-255 digital voltage signals, and the single-chip microcomputer mainly judges whether the circuit breaker has been disconnected by detecting whether the transmitted signal is zero. The microcontroller receives the zero signal, delays for 2ms, and detects the signal again. If it is still zero, it is determined that the circuit breaker has been disconnected, and then delays for about 8ms to send out the trigger IGBT signal.

Claims (2)

1. a kind of single-phase circuit breaker separating brake repeated breakdown analogue experiment installation, it is characterized in that, composition includes Triggered Vacuum Switch (TVS), pulse transformer (T), IGBT, current sensor (CT) and MCU, the Triggered Vacuum Switch (TVS) are attempted by open circuit On device (QF)；The primary coil of the pulse transformer (T) is connected by IGBT with DC power supply, the output signal of secondary coil Connect the trigger electrode of Triggered Vacuum Switch (TVS)；The grid of the IGBT connects the output port of MCU；The current sensor (CT) It is switched off device egress line to pass through, the input port of output termination MCU.

2. single-phase circuit breaker separating brake repeated breakdown analogue experiment installation according to claim 1, it is characterized in that, the electric current passes Sensor (CT) uses Rogowski coil.