Device and method for quickly measuring insulation resistance of DC power supply to ground

Abstract

The invention provides a fast measurement device and method for insulation resistance to the ground of a DC power supply. The fast measurement device comprises a voltage dividing resistor R1, a voltage sampling resistor R2, a first controllable relay contact K1, a first comparison resistor R4, a second controllable relay contact K3, a second comparison resistor R3, a third controllable relay contact K2 and a sampled voltage measurement unit, and is characterized in that the voltage dividing resistor is connected with a positive bus of a DC power supply to be measured, the voltage sampling resistor is connected with the voltage dividing resistor in series, the first comparison resistor and the first controllable relay contact K1 in series, and the first comparison resistor and the first controllable relay contact K1 are connected with the voltage sampling resistor in parallel; the second controllable relay contact K3 and the third controllable relay contact K2 are connected in series, the second controllable relay contact K3 and the third controllable relay contact K2 are connected with the voltage sampling resistor in parallel, and the second comparison resistor R3 is connected with the third controllable relay contact in parallel; and the sampled voltage measurement unit is connected with the voltage sampling resistor in parallel and used for measuring voltage at both ends of the voltage sampling resistor. The fast measurement device and method overcome defects of a bridge balancing method, a low-frequency AC signal method and a leakage current method, and are high in detection accuracy and high in detection speed.

Description

technical field [0001] The invention relates to the technical field of measurement and testing of aerospace vehicle control systems, and more particularly, to a device and method for quickly measuring the insulation resistance of a DC power supply to ground. Background technique [0002] The ground-to-ground insulation resistance test of the DC power supply of aerospace vehicles and ground equipment is one of the important items in the testing of aerospace vehicle control systems. Whether the insulation resistance is qualified or not directly affects the reliability of the aerospace vehicle control system and the success of launch. Leakage refers to the phenomenon that the insulation condition between the positive or negative power line of the aerospace vehicle system and the equipment casing is abnormal, resulting in an insulation resistance Ri<20MΩ. The phenomenon that the insulation resistance Ri<20MΩ between the positive line of the power supply and the equipment c...

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Problems solved by technology

The bridge balance method uses the insulation resistance of the DC positive and negative poles to the ground and two artificially set resistances to form a balanced bridge for insulation detection. The method is to add a low-frequency AC voltage source between the DC bus and the ground to obtain the value of the resistance of the DC bus to ground and the fault branch, but the detection results are greatly affected by the distributed capacitance of the system, and the injected low-frequency AC signal will affect the DC The voltage produces interference; the leakage current detection method is to connect a micro-current sensor in series with the DC power supply, and obtain the value of the resistance of the DC bus to ground and the fault branch through Ohm's law. The disadvantage is that the accuracy and sensitivity of the detection are not ideal. difficult to detect

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