An arc detector for a RF power supply system, where the RF power supply incudes a first RF power supply and a second RF power supply. A signal applied to a non-linear load varies in accordance with an output from one of the first RF power supply or the second RF power supply. The signal has a frequency. During an arc or arc condition in the non-linear load, the frequency of the signal changes, and if the frequency is outside of a selected range, an arc or arc condition is indicated. The frequency can be determined by digitizing the signal into a series of pulses and measuring a time or period between pulses.

A method of determining polymerisation of transformer insulation within a transformer. The method includes the steps of measuring a first and second moisture activity of oil in a transformer, and a first and second temperature of the transformer. The method further includes calculating the ratio of the gradients of the moisture equilibrium curves associated with the moisture activity and the temperature. The calculated ratio can then be used to characterise the polymerisation of the insulation and age of the transformer.

Evaluating the performance of an X-ray tube by: recording arcing events that occurred during the use of the X-ray tube; classifying the arcing events by severity; generating, on the basis of the classified arcing events, a first growth pattern for occurrences of arcing events; and determining a level of bubbles in the X-ray tube by finding, on the basis of the first growth pattern, a matching second growth pattern associated with a known level of bubbles in the X-ray tube. An X-ray tube may be checked and replaced in a timely manner, without the need for an on-site inspection, by remotely predicting trends or patterns for growth of levels of bubbles in the X-ray tube.

A method for identifying one or more simultaneously occurring partial discharge sources from partial discharge measurement signals of an electrical device to which an AC voltage is applied includes determining area parameters of at least one enclosed area of partial discharge pulse matrix arrays. For each enclosed area of partial discharge pulse matrix arrays, area parameters of the enclosed area of partial discharge pulse matrix arrays are compared to predetermined rule sets. Predetermined fault rules are applied which allocate characteristic partial discharge pulse area basic forms and characteristic combinations of partial discharge pulse area basic forms to known partial discharge sources, to the ascertained partial discharge pulse area basic forms in order to determine those partial discharge sources which have rendered the corresponding partial discharge pulses.

Electrical bushing for medium and high voltage, the bushing including a fluid filled insulation volume; a sensor unit in contact with the fluid in the fluid filled insulation volume; wherein the sensor unit is configured to measure a breakdown voltage of the fluid.

A transformer hydrogen gas monitoring system according to an embodiment of the present invention may comprise: a sensor module, which is disposed to allow at least a part thereof to meet hydrogen gas in a transformer and measures a resistance value of a member having a variable resistance value according to a hydrogen concentration in the transformer; and a multi-task module for receiving a sensing result of the sensor module, generating hydrogen concentration information corresponding to resistance value information included in the sensing result, and remotely transmitting information corresponding to the generated hydrogen concentration information.

An arc detector for a RF power supply system, where the RF power supply incudes a first RF power supply and a second RF power supply. A signal applied to a non-linear load varies in accordance with an output from one of the first RF power supply or the second RF power supply. The signal has a frequency. During an arc or arc condition in the non-linear load, the frequency of the signal changes, and if the frequency is outside of a selected range, an arc or arc condition is indicated. The frequency can be determined by digitizing the signal into a series of pulses and measuring a time or period between pulses.

A monitoring device and a method for monitoring an insulation resistance for an ungrounded electric system includes a liquid cooling operated to ground and having refrigerant flowing in tubes. For this purpose, the measuring signal is supplied in series in the tube system via the refrigerant resistance. The monitoring device is realized having a current measurement or a voltage measurement at the tube sections in order to detect the insulation resistance and can be enhanced for monitoring a shared insulation resistance of several ungrounded electric subsystems fed by a shared transformer.

A fault gas detection system for a liquid filled high voltage transformer, the transformer including a main tank and an expansion tank the tanks fluidic connected by an exchange conduit such that gas and/or a transformer liquid is able to exchange between the tanks, the gas detection system including: a chamber with a top cover, a predefined horizontal level-plane in the chamber defining a maximum liquid level of a transformer liquid in the chamber during use, a fluid-channel including a fluid-egress at a level equal to or higher than the top cover and a fluid-ingress lower than the level of the level-plane, a level sensor designed to measuring and/or indicating a liquid level.

A respective transformer and a respective wind turbine system is also provided.

An apparatus and test method for simulating spark discharge of a high-voltage electrostatic precipitator are provided. The simulation apparatus includes a pulse power supply configured to provide a test voltage, an anode cylinder configured to simulate an anode of a precipitator, a cathode rod configured to simulate a cathode of the precipitator, a pulse capacitor unit configured to simulate an electrode capacitor of the precipitator, an insulating support configured to hang the cathode rod, a voltage divider configured to measure an electrode voltage, and a grounded current sampling unit configured to measure grounded current. The simulation apparatus simulates a discharge process of the high-voltage electrostatic precipitator to measure discharge characteristic parameters such as discharge current and discharge energy of the high-voltage electrostatic precipitator. In this way, characteristics of spark discharge of the precipitator under different load conditions are simulated.