Study On Scm Based Test Devices Of Residual Current Protective Device Operating Characteristics

With the development of the electrification of industry and agriculture, electric energy has played an indispensible role in our life. Nowadays, more and more electrical equipments are used and popularize. This implicates various problems such as leakage accidents caused by improper using of electrical equipment or faulty circuit. Leakage accident may cause fire, equipment damage and personal injury. In order to protect the safety of individual and the electrical equipment, the residual current operated protective devices must be installed into the circuit . When the residual current reaches the threshold, the residual current operated protective device is activated and the circuit is cut off, avoiding injuring people and burning equipment.A detection device of residual current operated was designed, which meets the requirements of GB16916.1-2003, GB16917.1-2003, GB14048.2-2008 , that is under the conditions of 2.5, 10, 20, 50, 100, 200, 500A. Based on PIC16F877A control system, electric voltage regulator and low voltage high current transformer are combined for the device to generate high current. The residual current is sampled by utilizing current transformer and zero sequence current transformer, meanwhile the intelligent design is achieved by man-machine interface system. This detection device has the advantage of high output power and accuracy. It can be widely used in large current residual current test.