An over-voltage protection system is provided for use with electrical equipment. The system includes a protection circuit having a first bus for receiving electrical power, a second bus for providing power to the equipment and two parallel surge arresters connected between the first bus and ground. A main and backup bushing are arranged in parallel between the first and second bus. The main bushing is arranged in series with a normally closed contact maintaining the main bushing in service by default. The backup bushing is arranged in series with a normally open contact isolating the backup bushing by default. The protection circuit comprises a controller for testing the insulation of the arresters and bushings. The controller is configured to selectively actuate the contacts to selectively isolate, or incorporate, the arresters and bushings in the circuit to facilitate testing and maintenance while maintaining the protection circuit operational.

The present disclosure includes: a signal generation unit for applying a pulse signal to an electric line; a signal measurement unit for measuring the voltage of an applied pulse signal from the ground, when the pulse signal is applied to the ground through insulation resistance; an average voltage calculation unit for calculating the average voltage of the voltages measured during a period depending on sampling intervals; and a control unit for calculating the sampling intervals on the basis of an initial sampling interval and a preset time multiple, calculating the average voltage during the sampling period according to the calculated sampling intervals, and, according to whether the difference between a calculated first average voltage and a second average voltage measured before the first average voltage is within a first error range, detecting the first average voltage as a normal voltage, or calculating the sampling intervals by applying different time multiples thereto.

A charging controller carries out charging control of a power storage mounted on a vehicle. The vehicle includes a DC charging inlet. The charging controller carries out first charging control when a charging cable which is not a prescribed charging cable is connected to the DC charging inlet and carries out second charging control when the prescribed charging cable is connected to the DC charging inlet. For example, a time period for ground fault detection carried out during charging of the power storage is set differently between first charging control and second charging control. Alternatively, a response delay margin of a charging command is set differently between first charging control and second charging control.

An approach to detecting partial discharge events involves retrofitting an electrical system to include a capacitive sensor configured to capacitively sense partial discharge events of a component of the electrical system. The capacitive sensor has a first electrical conductor that forms a first terminal of the capacitive sensor, a second electrical conductor that forms a second terminal of the capacitive sensor, and a dielectric that separates the first electrical conductor and the second electrical conductor. The capacitive sensor generates an electrical sensor signal at an output of the capacitive sensor in response to the partial discharge event. The electrical sensor signal is converted to an optical signal and the optical signal is processed to detect an occurrence of the partial discharge event.

A system for real-time continuous and remote monitoring of the progressive degradation of insulators installed in Electric Power Transmission Networks, namely in Very High Voltage electric Lines (VHVL), which can be applied at lower voltage levels (High and Medium Voltage). The principle of operation is based on the identification of the occurrence of leakage currents in the insulators by registering the current intensities, the periods of the occurrences, and local measurements of temperature and relative humidity.

A mechanical reliability testing platform for tri-post insulators in a GIL device includes a horizontal-GIL-arrangement-form fixed-tri-post-insulator mechanical reliability verification testing platform for a horizontal dynamic insertion and extraction test, and a turning-GIL-arrangement-form fixed-tri-post-insulator mechanical reliability verification testing platform for a vertical dynamic insertion and extraction test. A driving unit is employed to realize the insertion and extraction of the conducting rod of the sliding-tri-post-insulator GIL form unit at the contact holder, so as to simulate the reciprocating forces on the fixed tri-post insulator induced by the thermal expansion and contraction of the pipe during the actual operation of the GIL, and simulate the working condition of the fixed tri-post insulator under abnormal forces when the GIL experience foundation settlement.

A system for on-line bushing monitoring and geo-magnetically induced current monitoring utilizes a Hall Effect current transducer and obtains the harmonic component of the signals through the measurement of bushing test tap current which provides a more reliable measurement method since the bushings provide a capacitive voltage divider that is not subject to saturation which is a drawback of using current transformers to obtain the signals. The system combines the existing harmonic analysis functions of the bushing monitor measurement system with the measured neutral direct current to provide an economical and efficient system that monitors both bushing condition and GIC conditions with one common monitoring module.

A method of performing line insulation monitoring of a pair of conductor lines at least partially located in a cable is provided, comprising the steps of providing a first power switch in a first conductor line of the pair and a second power switch in a second conductor line of the pair, providing a line insulation monitor at a first end of the pair of conductor lines, electrically connected to the pair of conductor lines, at the second end of the pair of conductor lines, electrically connecting the first and second conductor lines, placing the first and second power switches into a monitoring configuration wherein the first power switch is closed while the second power switch is open, and using the line insulation monitor to monitor the insulation of the conductor lines.

A high voltage system including: a high voltage bushing having a bushing body configured to be assembled with a tank filled with a dielectric liquid wherein the bushing body has a cavity, and the bushing includes a dielectric liquid level sensor configured to measure a dielectric liquid level in the cavity, and a temperature distribution determining device configured to determine a heat distribution in the bushing based on the dielectric liquid level measured by the dielectric liquid level sensor.

The present invention relates to a method and monitoring device, for monitoring N number of transformer bushings operating in substantially the same environment. N being any number more than 1. The method comprises estimating an absolute value for the capacitances of each of the bushings, the absolute values for the capacitances being denoted C.sub.x, and estimating an absolute value for the loss factor or the power factor of each of the bushings, the absolute values for the loss factors or the power factors being denoted F.sub.x. X is a number representing which bushing the value is associated to and X larger than 1. The method further comprises calculating Δ-values for all C values and Δ-values for all F values, according to:

ΔC.sub.X=C.sub.X−C.sub.X+1, for all values up to, and including, ΔC.sub.N−1,

ΔC.sub.N=C.sub.N−C.sub.1, for ΔC.sub.N,

ΔF.sub.X=F.sub.X−F.sub.X+1, for all values up to, and including, ΔF.sub.N−1,

ΔF.sub.N=F.sub.N−F.sub.1, for ΔF.sub.N,

and determining whether the Δ-values are within predefined ranges.