The Research On The Test System Of DC Relay’s Electrical Properties And Experiment

In DC system, the relay is widely used in automatic control, telecommunication,remote control, telemetry and power electronic devices. It is one of the most importantcontrol devices, and its long-term reliability will directly affect the reliability of the system.In this thesis, several DC interruption techniques are presented, including variousenergy dissipation modes，compulsive current zero mode, series-parallel connection methodand so on. The principles, superiorities, shortcomings and validity of some frequently usedmethods are summarized and analyzed.In order to research DC interruption, a set of test system of relay’s electrical propertiesis designed, which is based on the technique of virtual instrument. The system can acquireand store the voltage and current waveforms, and it has the function of automatic detectionand on-line alarm. Furthermore, this thesis focuses on the design of signal acquisitioncircuit. Holzer voltage sensor, resistor divider circuit and resistance-capacitance dividercircuit are discussed, and then we take the waveform which acquired by high voltage probeP6015A as the standard to check others. After that the ultimately acquisition circuit basedon resistance-capacitance divider is determined.Meanwhile, electrical properties experiments are performed respectively with fourtype relays, including AEV18012, LEV200, G18SP and G50WF. The experimental resultsshow that, the influence of the voltage and current on making arc duration is not obvious.That is to say the making arc duration doesn’t present monotonically trend with the changeof contact voltage and current. Generally, the breaking arc duration presents the trend ofincrease with the increase of the voltage. For most conditions, the breaking arc durationalso presents the trend of increase with the increase of the current; but due to the dispersion,the data of individual conditions don’t follow the rule, such as AEV18012.