Solid-state circuit breaker RCD buffer circuit integrating fault locating function and fault point detection method

Abstract

The invention provides a solid-state circuit breaker RCD buffer circuit integrating fault locating function and a fault point detection method. The solid-state circuit breaker RCD buffer circuit comprises a RCD buffer circuit. One end of a capacitor Cs is connected with a collector of V1, the other end of the capacitor Cs is connected with a resistor Rs and the anode of a diode Ds, and the other end of the resistor Rs is connected with signal ground. One end of a relay Ts is connected with the cathode of the diode Ds, the other end of the relay Ts is connected with the collector of V2 and shares a control signal with an isolation switch T for controlling connection when a diode Ds branch plays buffering effect and disconnection during a fault positioning process. Accurate positioning of a fault point can be realized by controlling the action of an isolation switch, a relay and a solid-state circuit breaker while effectively suppressing the over-voltage shutdown. The solid-state circuit breaker RCD buffer circuit is used for the rapid troubleshooting of a DC microgrid to ensure the reliability and security of a system, improve the utilization of the device and reduce the size and cost of a protection device. The topology is simple, and the application feasibility is ensured.

Description

Technical field [0001] The invention belongs to the technical field of DC microgrid, and relates to the protection and detection of DC microgrid busbar faults, in particular to a solid-state circuit breaker RCD snubber circuit integrated with a fault location function and a fault point detection method. Background technique [0002] When a permanent fault occurs in the DC power grid, the circuit breaker cannot be reclosed again. In order to improve the reliability of power supply and the stability of the power system, the location of the fault should be quickly found to eliminate the fault. The existing fault location methods of DC microgrid transmission lines mainly include impedance method and traveling wave method. [0003] Impedance method is usually used as an additional function of microcomputer protection and wave recording device, which has the characteristics of starting fixed value quantification and low investment; but in DC microgrid, because the sensitive components in...

AI Technical Summary

Problems solved by technology

The single-ended traveling wave distance measurement does not need to transmit opposite data and is not limited by communication technology conditions. It has the characteristics of small investment, simple implementation, and high ranging accuracy. Reflection and other factors, there are situations such as difficulty in identifying radiation waves; the double-ended method only recognizes the head of the traveling wave, and does not need to distinguish the reflected wave, and the ranging accuracy is high, but the double-ended method requires that the devices on both sides should be connected A stable and stable clock signal source and requires high reliability of the communication lines on both sides, otherwise it is easy to cause ranging failure

In addition, whether it is single-ended traveling wave ranging or double-ended traveling wave ranging, additional electrical equipment is required to increase investment, and the start-up setting cannot be quantified. In actual operation, the start-up threshold setting is often low. Easy to start by mistake

[0005] Therefore, the above two distance measuring methods have certain limitations under certain conditions.

[0006] In addition, when the DC microgrid fails, since there is no natural current zero-crossing point in the AC system, the current rise rate di / dt of the solid-state electronic switch (SSCB) at both ends during the opening process and the off-state during the turning-off process The voltage rise rate du / dt is very large, which may cause damage or breakdown of power devices

In addition, even if the solid-state electronic switch completes the turn-off action, the energy stored in the inductance on the line will generate an excessive voltage at both ends of the device. If no effective measures are taken, the DC solid-state electronic switch will operate at high current and high voltage. under hard shutdown, which will make it suffer a huge shock or even damage the

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