A Finite Element Model of Partial Discharge in Solid Medium

The mechanism of partial discharge(PD) is the theoretical basis of the PD detection, insulation monitoring and risk assessment. The finite element analysis of partial discharge is an effective measure to study the characteristics of PD. In this work, a physical model of PD of a gas gap in solid dielectric using finite element analysis (FEA) method has been developed to determine the relationship between the inception electric field with different applied stresses, the cavity diameter and air pressure has been considered as the physical parameters that affect PD characteristics. The change of potential distribution before and after the discharge and the field strength during the discharge are analyzed.

Insulation Monitoring of Dynamic Wireless Charging Network Based on BP Neural Network

The transmission cable and power conversion device need to be buried underground for dynamic wireless charging of an expressway, so cable insulation deterioration caused by aging and corrosion may occur. This paper presents an on-line insulation monitoring method based on BP neural network for dynamic wireless charging network. The sampling signal expression of the injection signal is derived, and the feasibility of this method is verified by experiments, which effectively overcomes the problem of large calculation error of insulation resistance when the cable capacitance to ground is large. The experimental results indicate that the error of the proposed method is less than 9%, which can meet the needs of insulation monitoring.

Simulation of the insulation monitoring system of the high-voltage electrical network of a vehicle with a hybrid power plant

The paper presents the results of mathematical and simulation modeling, as well as calculated and experimental dependencies, which make it possible to evaluate the operation of the insulation resistance monitoring system of the high-voltage power grid of a hybrid vehicle. The work also provides circuits for measuring insulation resistance, a mathematical model in the MATLAB Sim-ulink environment, and the peculiarities of the operation of the software and hardware simulation complex. The aim of the work is to obtain the most reliable mathematical and physical model of insulation resistance, to determine the architecture of a high voltage battery with the IRM system included in it, to identify the key functions and characteristics of the IRM system, to test the simulation system. The introduction justifies the importance of the IRM system and provides references to standards that govern the requirements for measuring and identifying utility faults. The block diagram of the high voltage battery control system is presented. The composition of its main elements is described. The functions and key characteristics of the IRM system are considered, typical characteristics of insulation monitoring systems are given. A schematic diagram of determining the insulation resistance of conductors and an electric circuit is clearly considered. An equivalent circuit of a differential DC amplifier with a unipolar power supply is presented, which is used to amplify small differential voltages on a shunt when changing large common-mode voltages, which is part of the measuring circuit. Mathematical and simulation modeling was carried out to evaluate the method for calculating the insulation resistance according to the well-known scheme, which is used when measuring using the three-voltmeter method. There was considered the mode of checking the the insulation control system, when several test procedures performed containing simulation of the fault and operating condition of the insulation by connecting and measuring the test resistance. The results of physical simulation of the IRM system and measurement of insulation resistance, voltage between each of the high voltage supply wires and the high voltage battery case, voltage between the wires, battery voltage were obtained. The actual insulation resistance was calculated. The conclusions explain the effectiveness of physical and simulation modeling, obtaining a reliable mathematical model and low error in modeling the insulation characteristics.

Mathematical modeling of a system for monitoring the insulation resistance of a high-voltage power grid of a hybrid vehicle

The paper presents mathematical models and computational and analytical dependences, which make it possible to implement a system for monitoring the insulation resistance of a high-voltage power grid of a hybrid vehicle and make it possible to formulate requirements for the physical and simulation model of the software and hardware complex of laboratory tests. The purpose of the work is to determine the main functions and characteristics of the insulation monitoring system, its features, the principle of operation and methods of monitoring the insulation resistance, drawing up requirements for the simulation system. The introduction justifies the importance of monitoring in-sulation resistance and provides references to standards that regulate the requirements for the meas-urement and determination of mains failure. The block diagram of the vehicle power supply and the role of the insulation resistance monitoring system in this diagram are presented, the features of in-sulation monitoring are explained. The principle of operation of the insulation monitoring system and the use of the most common schemes are considered. The calculated dependencies for each of the presented schemes are given. These allow calculating the insulation resistance. The procedure for measuring the insulation resistance according to the ISO standard is described and the corre-sponding equations are given. For the presented circuit, a graph that explains the principle of the system's operation, when one of the keys is closed, the voltage across the measuring resistor changes with the normal insulation state of the positive and negative power supply bus of the high-voltage system is given. The conclusions provide a generalization of the presented mathematical model and formulate the requirements for the software and hardware complex, which allows simulation and mathematical modeling of electrical systems and their components in various operating modes. The paper explains the features of the software and hardware complex that allows to simulate changes in the insulation resistance and faults of the high-voltage power supply network for a vehicle with a hybrid power plant.