DC Insulation Parameter Characteristics of XLPE in the Course of Its Aging

This paper deals with the experimental study on the correlation betweeninsulation resistance (R) and direct current (DC) component (i_(de)) and corresponding aging degreeof insulation in the course of the aging within cross linked polyethylene (XLPE) insulation. Theaging tests were performed on a section of 10 kV transmission XLPE cable by means of water needlemethod, and _R was measured by DC voltage superimposed method, R and i_(de) were found to besignificantly dependent on the correspondingaging degree of insulation in the course of aging ofXLPE, and different kind of aging stage has different characteristics. Beside, there are generallysimilar regularity but different amplitude in the course of aging of XLPE insulation in differentelectrolyte, and the various electrochemical tree were found on the surface of aging XLPE cableimmersed in CuSO_4, solution. Therefore, according to the changing regularity of the DCcharacteristic parameters i. e. R and i_(de) within XLPE insulation judging the aging degree of XLPEinsulation will be an effective method.

Effect of Moisture on the Insulation Condition of Twisted Coils

Method IEEE 841 is used to test endurance of insulation system of stators to 100% humidity at 40 ℃ for168 h. Insulation resistance after this test between phases or between phase and frame has not been lover as 5 × 10^6 Ohm. Some producers of motors use this method for determining quality of impregation resin. On such test insulation resistance between phases was lover as between phase and frame. Because between phases is only wire insulation impregnating resins on insulation resistance of insulation system an impregnating resin we observe influence of type of wires and after humidity test. With diagnostic of insulation, the state is dealt. We compare our impregnation resin with competitive impregnation resin. We made test on twisted coils prepared after STN IEC from two parallel wires. In this test, we succeed in demonstrating that the main influence on insulation resistance of insulation system wire and impregnation resin has insulation of wire. Impregnation resin has influenced on data dispersion.

HIGH VOLTAGE SAFETY MANAGEMENT SYSTEM OF ELECTRIC VEHICLE

In order to improve the drivability and energy efficiency of electric vehicle （EV）, more and more batteries are connected in series with high voltage which makes it necessary to monitor the electric parameters of high voltage system （HVS） to ensure the high voltage safety. A high voltage safety management system is developed to solve this critical issue. Several key electric parameters including pre-charge, contact resistance, insulation resistance and remaining capacity are monitored and analyzed based on the presented equivalent models. An electronic unit called high voltage safety controller is developed. By the help of hardware-in-loop system, the equivalent models integrated in the high voltage safety controller are validated and the on-line electric parameters monitor strategy is discussed. The real vehicle experiment results indicate that the high voltage safety management system designed is suitable for EV application.

Modeling Relative Humidity Effects on Power Electronic Performance

Variations in the behavior of power supplies caused electrical behavior dependence with environmental conditions. by environmental conditions require accurate characterization of the This paper introduces models to help predict relative humidity （Rtt） and other environmental factors influence on sensitive circuitry in power electronic systems. The resistivity and permittivity of an insulator have been modeled using different water contents i.e. RH, such model also included the mechanical properties of the design. An application example of a high power density, high voltage DC-DC converter is used to verify the results.