Method and device thereof for fault detection/protection for SVC system

Abstract

The invention discloses a method and a device thereof for fault detection / protection for an SVC system, and relates to a dynamic reactive power compensation system and a method thereof. The device of the invention consists of a signal acquisition unit, a singlechip control unit, a CAN communication unit, a fault detection / protection and trigger pulse driving unit, a thyristor valve unit and a photoelectric isolation unit. The detection / protection method of the invention comprises that the acquisition unit sends voltage and current to a CPU and sends out trigger pulse; the photoelectric isolation unit receives data, and blocks the trigger pulse when serious fault is judged so as to protect the thyristor valve unit and other high-voltage equipment; and a CAN bus uploads fault alarms such asunder voltage, BOD, overtemperature and the like to the CPU. The detection / protection method and the device thereof effectively solve the problems of delayed protection of the conventional system, inaccurate fault signal indication, false operation of the system and the like, meanwhile save the cost, reduce the workload of field assembly, and greatly improve the stability and security of system operations.

Description

technical field [0001] The invention relates to a dynamic reactive power compensation system, belonging to the technical field of flexible AC power transmission, in particular to a fault detection / protection method and a device thereof for an SVC system. Background technique [0002] In recent years, with the continuous increase of high-power nonlinear loads, the reactive power impact and harmonic pollution of the power grid are on the rise, causing problems such as voltage and current distortion, three-phase imbalance, and low power factor. In order to solve the above problems, a static dynamic reactive power compensation device (SVC) can be installed. At present, the SVC device has been successfully applied to the compensation of impact loads such as metallurgy, mining and electrified railways. Phase-splitting reactive power regulation, reliable operation, and wide application range, so it plays an obvious role in power system voltage stability and power quality improvemen...

AI Technical Summary

Problems solved by technology

[0003] At present, the voltage level of commonly used thyristors is up to 7000V, and the series-parallel connection of thyristors makes the main circuit and control circuit of TCR more complicated. The previous fault detection method is to directly connect various alarm signals of the thyristor valve group with the CPU control board After connecting, the CPU will receive and judge which type of fault signal it is, and then make corresponding actions to block the pulse, cut off the main circuit or just give a simple alarm indication

Its disadvantage is that a lot of connecting wires and optical fibers are used, especially in high-voltage and large-capacity SVC devices, which often require as many as 300 or more optical fibers, which increases a large part of the cost virtually, and brings great inconvenience to the on-site installers. In many cases, the return signal is misconnected due to the problem of the line number identification, which makes the system fault signal indication inaccurate, the system malfunctions, the valve group protection is not timely or wrong protection, and the main circuit and power are burned in severe cases. On the other hand, because there are too many interfaces, devices such as CPLD or FPGA need to be added to assist the CPU to work, which increases its hardware cost and failure points accordingly, and because it occupies too many CPU resources, the workload of the CPU increases. Large, the system processing speed slows down, not only that, because all faults are judged by the CPU before processing, resulting in a delay in the protection signal, and the phenomenon that the protection is not timely, making it difficult for the system to run safely and stably for a long time

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