Interturn protection method of high-voltage shunt reactor based on parameter unbalance detection

Abstract

The invention discloses an interturn protection method of a high-voltage shunt reactor based on parameter unbalance detection, which is established on the basis of a time domain parameter model and comprises the following steps: calculating the electrical parameter of each phase under the least square significance by using the electrical quantities at the initial end and the tail end of the high-voltage shunt reactor; and identifying whether the interturn short circuit fault of the high-voltage shunt reactor occurs or not by constructing the comprehensive criterion of the parameter unbalance detection under the condition that the interturn short circuit faults of the three phases of the high-voltage split-phase shunt reactor can not occur simultaneously. The interturn protection method can not be influenced by system oscillation and frequency shift. The method is based on measurement and comparison of equivalent inductance parameters of each phase of the reactor, thus the setting process is simple and convenient, and the sensitivity is higher. Because the interturn protection detects the changes of each phase of the inductance parameters, the influence caused by system operation modes and faults on the basis of the sequence component detecting principle is avoided, and the interturn protection method can automatically adapt to the change of the installation position of a voltage transformer.

Description

technical field [0001] The invention relates to an inter-turn protection method of a high-voltage shunt reactor based on parameter unbalance detection applied to a power system, in particular to a detection and protection method for an inter-turn short-circuit fault of a high-voltage shunt reactor. Background technique [0002] High-voltage shunt reactors play an important role in improving the operating environment of power systems and improving system stability. With the construction and strengthening of ultra-high-voltage power grids in recent years, the number of high-voltage shunt reactors used in the system is increasing. According to the installation position of the high-voltage reactor, it can be divided into line shunt reactors, which are generally installed on long-distance transmission lines; the other type is busbar shunt reactors, which are generally installed on high-voltage busbars of substations with more short-distance outgoing lines. As an important part o...

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Problems solved by technology

The turn-to-turn protection principle based on the fault additional network faces two problems: 1), it is difficult to achieve a proper balance between sensitivity and reliability; 2), it cannot adapt well to the difference in the installation position of the voltage transformer, that is, When the voltage transformer is located on the bus side, the turn-to-turn protection malfunction problem, the schematic diagram of the shunt reactor of the transmission line is as follows figure 2 As shown, the schematic diagram of the bus shunt reactor is shown in image 3 As shown, it can be seen from the figure that due to the different positions of the voltage transformers, when the non-full-phase state or the switches are closed at different times, the position of the unbalanced additional power supply is similar to that of the internal fault, so the directional turn-to-turn protection based on the fault additional network bound to misuse

[0003] In the traditional technology, it is also possible to identify whether the inter-turn protection occurs by detecting the equivalent inductance of the shunt reactor or measuring the change of the impedance. The inter-turn protection principle model based on the equivalent inductance of the shunt reactor only considers the pure inductance model, which is bound to produce certain Principle error; the voltage value at the end of the reactor is used in the calculation, but there is no voltage transformer at the end in the field, so it is difficult to be practical. In addition, the value of this method is difficult to set

The turn-to-turn protection method of measuring impedance changes, because the phasor equivalent impedance amplitude change of each phase reactor is used to detect the turn-to-turn fault, affected by the system frequency and phasor calculation error, the sensitivity is not high

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