Novel active protection device in DC system

Abstract

The invention belongs to the technical field of power equipment, and particularly relates to a novel active protection device in a DC system. The circuit comprises a double-tube forward DC / DC converter, a single-chip microcomputer control circuit, an output diode and a detection circuit. The input end of the double-tube forward DC / DC converter is connected with the storage battery pack, and the output end of the double-tube forward DC / DC converter is connected with the direct-current load through the output diode; the single-chip microcomputer control circuit is connected with the driving endof the double-tube forward DC / DC converter and further connected with a transmission interface of the detection circuit, and a sampling port of the detection circuit is connected with an output diodeat the output end of the DC / DC converter. The single-chip microcomputer control circuit is also connected with a communication interface and a man-machine interaction interface. According to the invention, the functions of active isolation, active fault detection, active fault positioning and equipment protection of the AC-DC channeling line fault can be realized.

Description

technical field [0001] The invention belongs to the technical field of electric power equipment, and in particular relates to a novel active protection device in a direct current system. Background technique [0002] The DC system is an important part of the power secondary system. It is an indispensable structure in substations and power plants. It is the basis for power system control and protection, and it is also the guarantee to ensure that accidents can be dealt with quickly. The current DC system is mainly composed of rectification module system, monitoring system, insulation monitoring unit, battery pack, battery inspection unit, switch value detection unit, step-down unit, and power distribution unit, among which the battery pack is the core of the entire system. In the DC power distribution system, the AC circuit and the DC circuit are two independent systems. The AC circuit is generally a grounded system, while the DC circuit is a floating system. Therefore, when ...

AI Technical Summary

Problems solved by technology

Depend on figure 1 It can be seen that due to AC fault power supply U AC It is grounded and connected to the DC bus, so for the DC system, it is equivalent to a ground fault on the positive or negative bus, and for the AC system, the resistance R 1 , R 2 It forms a loop with the AC fault power supply, thereby outputting AC voltage, which affects the DC bus voltage. If the fault occurs at the DC positive pole, it will cause the possibility of malfunction of the protection; if it occurs at the DC negative pole, it will cause the protection to refuse to operate. possible

[0004] In the DC system, there are many deficiencies in the existing solutions for AC and DC line faults. The current portable detection technology for AC and DC line faults has a large amount of engineering, poor timeliness, low efficiency, and difficult to distinguish and accurately search. In addition, these methods cannot limit and isolate faults, and the fault phenomenon will further expand to the entire DC power distribution system, thus affecting the normal operation of the system

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