The application provides a gas density relay with online self-check function and its check method, including a gas density relay body, a first pressure sensor, a second pressure sensor, a temperature sensor, a gas chamber, a pressure regulating mechanism, an online check contact signal sampling unit and an intelligent control unit. The air path of the pressure regulating mechanism is connected to the gas pressure chamber and the second pressure sensor; Pressure rise and fall can be regulated through the pressure regulating mechanism to make the gas density relay body contact action. The contact action is transmitted to the intelligent control unit through the online check contact signal sampling unit. The intelligent control unit detects the action value and/or return value of the contact signal of the gas density relay body according to the density value when the contact acts, and completes the check work without requiring maintainer to go to the site for check. At the same time, because the pressure regulating mechanism is not connected to the SF6 gas path of the gas density relay body or electrical equipment, its sealing requirements are reduced, the reliability of the power grid is improved, and the manufacturing cost is reduced.

The present application provides a self-diagnostic gas density relay and a use method thereof, the gas density relay includes a gas density relay body, a gas density detection sensor, at least one diagnostic sensor, and an intelligent control unit; where the diagnostic sensor is configured to acquire deformation quantities of components that generate deformations, and/or positions or displacement quantities of components that generate displacements when the pressure changes, or the temperature changes, or the gas density changes in the gas density relay body; and the intelligent control unit is respectively connected with the gas density detection sensor and the diagnostic sensor, receives data acquired by the gas density detection sensor and/or the diagnostic sensor, and diagnoses a current working state of the gas density relay body. The present application is used for monitoring a gas density of the gas-insulated or arc-extinguished electrical equipment, and at the same time, on-line self-inspection for the gas density relay is completed, so that efficiency is increased, no maintenance is realized, operation and maintenance costs are greatly reduced, and safe operation of a power grid is guaranteed.

In a method for determining a fluid density of a fluid in an encapsulated electrical device a sensor unit is used to acquire measurement data. The fluid density is derived from the measurement values. Weather data relating to weather conditions in an environment of the electrical device are collected. Via machine learning, a digital model is generated for the influence of the weather conditions on a measurement deviation of a measurement value from the true fluid density. Using the digital model, a correction value is calculated for measurement values according to the weather data and a measurement value is corrected using the correction value.

The application relates to a method for determining a property of a fluid component of a fluid present in a compartment of an electrical apparatus by means of a measurement device arranged outside the compartment and comprising a chamber for receiving a quantity of the fluid from the compartment. Amongst other steps of the method, an optical path in the chamber is illuminated by a light source and a first intensity of light is measured by a light detector. Then fluid is released from the compartment into the chamber and a second intensity (Ix) of light is measured. Based on these measurements the property of the fluid component is determined.

A gas monitoring system includes a gas-insulated switchgear, wherein the gas-insulated switch gear has at least two separated chambers which are filled with an insulating gas surrounding high or medium voltage components. A first sensor is connected to the first chamber and a second sensor is connected to the second chamber, both sensors adapted to measure a physical property of the insulating gas in their respective chambers over time. A computer unit is adapted to calculate from the two sensor measurements a leakage rate of the insulating gas in one of the two chambers using an adaptive filter, in particular a Wiener filter.

An optimized method of monitoring a circuit breaker containing a gas with at least one gas characteristic providing a numerical value includes the steps of a) collecting a dataset referring to the at least one gas characteristic inside the circuit breaker, wherein the dataset contains the numerical value of the at least one gas characteristic during a specific condition or specific time of the day, b) calculation of a standard deviation of the at least one gas characteristic of the datasets of at least 3 days of the last 10 days, c) comparing the standard deviation of the gas pressure with a predefined threshold value, and d) triggering a first action in case the standard deviation exceeds the threshold value.

A monitoring system for an enclosure having an arc quenching gas includes at least one fluid characteristic sensor in fluid communication with an interior the enclosure, and an electronic controller operatively coupled to the at least one fluid characteristic sensor. The electronic controller forecasts a maintenance event based on values received from the at least one fluid characteristic sensor.

A method and a facility for filling a high- or medium-voltage gas-insulated electrical apparatus in which the insulating gas comprises a mixture of heptafluoroisobutyronitrile ((CF.sub.3).sub.2CFCN) and carbon dioxide. The method and the facility using a mixture of (CF.sub.3).sub.2CFCN and CO.sub.2 in pressurised liquid form which is heated to a temperature no lower than the critical temperature of the mixture.

To improve the reliability of gas space monitoring of a gas space (17) of an electrical system (40) filled with a harmful gas, the invention provides a multi-path valve device (44) for connecting a density monitor (20) to a system to be monitored for gas density, comprising a first gas connection (13) for connecting the valve device (44) to the system, a second gas connection (14) for connection to the density monitor (20), a third gas connection (15) for connection of a testing device (19) for testing the function of the density monitor (20), and switching device for selectively connecting the second gas connection (14) to the first gas connection (13) or the third gas connection (15).

The application relates to a method for determining a property of a fluid component of a fluid present in a compartment of an electrical apparatus by means of a measurement device arranged outside the compartment and comprising a chamber for receiving a quantity of the fluid from the compartment. Amongst other steps of the method, an optical path in the chamber is illuminated by a light source and a first intensity of light is measured by a light detector. Then fluid is released from the compartment into the chamber and a second intensity (Ix) of light is measured. Based on these measurements the property of the fluid component is determined.