Capacitive divided voltage sensor

Abstract

The capacitive division voltage transformer relates to the electric quantity information transformation technology which is applicable to power system, specially for linearly transforming primary high voltage into secondary low voltage as information input for measurement, protection and control system in 10 kV power system. It is mainly formed from primary electrode, secondary electrode, grounding electrode, insulating material, primary terminal, secondary terminal, base plate, interface relay and metal shielding case.

Description

Technical field: [0001] The invention relates to a capacitive voltage divider voltage sensor, which is suitable for power systems, especially 10kV power systems, to linearly transform the high voltage on the primary side into the low voltage on the secondary side as a sensor for measurement, protection and control. The technology of power information conversion of system information input. Background technique: [0002] At present, the traditional power system voltage converters are all voltage sensors with iron core coil structure. The advantage of these voltage sensors as voltage information converters in high voltage systems is that they use the principle of electromagnetic induction to make the primary and secondary circuits Electrically isolated, information is transmitted through changes in the magnetic field. Therefore, it is easy to realize the isolation of the high-voltage primary side and the low-voltage secondary side, so that the secondary equipment and personal...

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Problems solved by technology

[0004] 1. Due to ferromagnetic saturation, the relationship between the primary measurement value of the transformer and the secondary signal is nonlinear. In order to obtain the linear relationship between the primary and secondary signals, either the measurement range is very narrow; To the extent that can be tolerated, at the same time, the electromagnetic parameters cannot be coordinated;

[0005] 2. Traditional transformers provide information to electromagnetic instruments and relays. The measurement, protection or control system composed of electromagnetic instruments and relays is an analog passive system, which requires strong analog information and large capacity ( Generally 100V, 15VA or more), so the volume is large and the weight is heavy

The above-mentioned domestic and foreign voltage sensors all use the principle of resistance voltage division, and the accuracy is not higher than 0.5 grades. The use of resistance voltage division will also cause the following problems: because there are metal resistors directly connected on both sides of the high and low voltage, if the grounding terminal of the high voltage is once The high voltage of the primary side will appear on the secondary side of the open circuit. It can be seen that the high and low voltage cannot be effectively isolated; the high voltage resistor is surrounded by a radiating high voltage electric field, which is not only a source of electromagnetic interference, but also increases the burden on the insulation structure; Usually the radius of the resistive element is very small, which will increase the amount of partial discharge

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