Smart Power Grids Research Of Dc System Insulation Detection Device

Direct-current played an important role in power system,its primary task was providing power for power plant and all kinds of monitoring protection device and operation circuit in transformer substations.Whether the DC system worked normally determined that the power system would work safely stably or not.Branch ground was a kind of common insulation failure malfunction,and usually the working DC system could not be badly influenced by one spot grounding.However,if the malfunction could not be located and solved in time,there might be DC power short circuit or protection device wrong action or even other serious results when several spots grounded.So it was very necessary to run the real-time detection for the sake of ringing the alarm when one spot grounding occurred and avoiding more serious power accident.The paper listed several traditional methods of insulation detection,analyzed the advantages and disadvantages of common methods of power bridge counterpoising,AC injection and DC leak current detection.Beyond the methods above,the paper proposed a new detection solution,that was combining the step detection with the DC leak current sensor,and introduced the development of hardware and software of the DC system insulation detection device in the smart power grid.The hardware of the device consisted of sampling circuit,primary control circuit and alarm display circuit.A chip with the type of PIC16F1946 was employed as the core controller.The hardware circuit was divided into several module by their different functions,of which the principle design and communication control were accomplished in succession.According to the device function and system requirement,the paper programmed sampling module,communication module and display module respectively.