Circuit for improving load capacity of voltage sensor and circuit element constant value method

Abstract

The invention provides a circuit for improving the on-load capacity of a voltage sensor and a circuit element constant value method, and relates to the field of power distribution equipment. The circuit comprises a compensation reactor connected to the output end of a voltage division assembly of the voltage sensor, and a resonance suppression branch connected with the compensation reactor in parallel; the resonance suppression branch is used for suppressing the resonance phenomenon between the compensation reactor and the voltage division assembly and between the compensation reactor and the output side equivalent capacitor, wherein the input end of the compensation reactor is connected with the output end of the voltage division assembly, and the output end of the compensation reactor is connected with the output end of the voltage sensor. The resonance suppression branch comprises a branch capacitor and a branch resistor which are connected in series or only comprises a branch resistor. The circuit is suitable for a three-phase voltage sensor and a zero-sequence voltage sensor, and by optimizing the structure of the compensation circuit, the improvement of the loading capacity of the voltage sensor under power frequency and the suppression of high-frequency harmonic noise are both considered.

Description

technical field [0001] The invention relates to the field of power distribution equipment, in particular to a circuit for improving the load capacity of a voltage sensor and a value determination method for circuit elements. Background technique [0002] The primary and secondary integration of power distribution equipment is an important way and means to realize local fault handling, and it is the only way for power distribution equipment to be standardized, miniaturized, device integrated and intelligent in operation and maintenance. Three-phase voltage sensors and zero-sequence voltage sensors are important components of primary and secondary fusion equipment. At present, the voltage sensor mainly has two typical structures: impedance divider and CVT, and the voltage sensor based on capacitive divider is the most widely used. The rated output voltage is obtained for subsequent circuits. The main problem of this type of circuit is: when the capacitance of the high-voltag...

AI Technical Summary

Problems solved by technology

The main problem of this type of circuit is: when the capacitance of the high-voltage capacitor is large, the capacitive current flowing on the voltage sensor is large, which will affect the normal operation of the power line and affect the correct judgment of the relay protection device; the capacitance of the high-voltage capacitor When it is small, the load capacity of the voltage sensor is poor, and the connection cable between the sensor and the measurement and control device and the input impedance of the measurement and control device will affect the accuracy of the sensor

To sum up, the main disadvantage of the existing technical solution is: from the perspective of load capacity, the larger the capacitance of the internal capacitance of the sensor, the better, but at this time the capacitive current on the line becomes larger, and the reactive power on the sensor becomes larger. It is not conducive to the safe and stable operation of the distribution network, that is, there is a contradiction between the load capacity and the power consumption of the sensor

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