Distribution circuit electric voltage over-deviation protectors

Abstract

The invention discloses a distribution circuit voltage overdeviation protector, which comprises a voltage sampling rectification power supply (1), step-down voltage regulation rectification circuit (2), a voltage sampling circuit (3), an overdeviation voltage processor (4) and a cut-off circuit (5) of the distribution circuit of the voltage overdeviation. The protector can cut off the distribution circuit according to the set overdeviation voltage in the distribution circuit and the persistent time; in the voltage sampling circuit (3), the voltage of the stabilized voltage supply output by the step-down voltage regulation rectification circuit replaces the rated working voltage of the AC power supply and the voltage of the voltage sampling rectification power supply replaces the working voltage under various states of the distribution circuit to carry out subtraction and make the invention suitable for the protection of the line voltage and the HV distribution circuit and not limited by the electrical load capacity. The protector is arranged with a positive and negative deviation overdeviation voltage recording device, so the invention can monitor the quality of the power supply of the distribution circuit.

Description

technical field [0001] The invention relates to a voltage over-deviation protector for a distribution line, in particular to a protector capable of cutting off a distribution line with a voltage over-deviation within a time limit according to the magnitude of the voltage over-deviation. Background technique [0002] At present, according to the power supply quality standards stipulated by my country for low-voltage distribution lines, the allowable value of the voltage deviation is |ΔU 允 |=±7%U e , that is, the phase line overvoltage is U′ 允 ≤235.4V, phase line undervoltage is U″ 允 ≥204.6V; the allowable value under fault conditions is ±10%U e , namely U′ 允 ≤242V, U″ 允 ≥198V; U e is the rated working phase voltage AC 220V, ΔU (is the phase line deviation voltage) = U′-U e or U″-U e ; The International Electrotechnical Commission IEC and the country's insulation coordination standards stipulate that the maximum operating phase voltage allowed by electrical equipment i...

AI Technical Summary

Problems solved by technology

When taking the overvoltage, undervoltage, or overvoltage and undervoltage signal that the protective electrical equipment is endangered, the signal is the sum of the voltage deviation generated by the phase line voltage and the neutral line. When the working voltage of the phase line is relatively high, and the deviation voltage from the neutral line is large, after being superimposed on each phase, the working voltage of the phase line of the electric terminal may be high, resulting in the malfunction of the protector, and the action of the protector The value has to be selected higher, and the action value of the protector is greater than the power quality standard, and exceeds the voltage U specified in the insulation coordination standard of the electrical equipment. H , and there is a protection dead zone. In addition, the overvoltage distribution line is cut off according to a fixed time limit. It also exists that when a high working voltage occurs, the voltage cannot be cut off in a very short time that the person and the electrical equipment should be able to withstand. Higher requirements for power distribution lines, and endanger the safety of electrical equipment and personal safety; the fault voltage signal when the neutral point or neutral line deviation voltage is too large can only be in accordance with the insulation coordination standard of electrical equipment According to the regulations, the protective device is set for the over-deviation voltage generated by the neutral line of the distribution line, so it cannot protect the three-phase load from being relatively balanced, and the neutral point and the neutral line do not generate or the generated deviation voltage is small. And when the phase line overvoltage or undervoltage value of each phase is too large, it will cause harm to the electrical equipment, and a protection blind zone will appear; Hazards to electrical equipment

Images