Gas Density Relay Online Verification for SF6 Switchgear
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Solution Overview
Problem
High-voltage electrical equipment with SF6 gas faces operational safety risks due to gas density and moisture content issues, requiring regular testing but lacks efficient online monitoring solutions for reliable and remote condition assessment.
Innovation Solution
An electrical system with an online sampling and check function, incorporating a gas density relay, pressure regulating mechanism, gas density sensor, and intelligent control unit, which isolates the gas density relay from the equipment, regulates pressure, and samples contact signals to detect alarm or blocking signals, enabling remote monitoring and maintenance-free operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regular testing of SF6 gas density and moisture content is performed manually, then operational safety can be ensured, but the testing process requires manual intervention and cannot achieve continuous online monitoring
Solution Approach 1:
The gas density relay performs self-check through the pressure regulating mechanism that automatically adjusts pressure to trigger contact signals, and the intelligent control unit automatically samples and verifies contact signal values without manual intervention, enabling the system to monitor itself continuously
Solution Approach 2:
The system implements continuous online monitoring by continuously sampling contact signal values from the gas density relay and comparing them with standard values, ensuring uninterrupted surveillance of SF6 gas density and moisture content conditions
2Extent of automation
If online monitoring of gas density and moisture content is implemented, then remote control and telemetry requirements are met, but system complexity increases
Solution Approach 1:
The intelligent control unit serves multiple functions: it controls the pressure regulating mechanism, samples contact signal values from the gas density relay, compares values with standards, and manages the valve operations, consolidating multiple monitoring and control functions into a single device to minimize system complexity while achieving remote monitoring capabilities
Solution Approach 2:
The pressure regulating mechanism acts as an intermediary that automatically adjusts pressure to trigger gas density relay contact signals, enabling the system to verify relay functionality without direct manual intervention, thus simplifying the remote monitoring implementation
3Reliability
If the gas density relay is isolated from the electrical equipment via valve closure, then online check can be performed without affecting equipment operation, but the check process requires additional control mechanisms
Solution Approach 1:
The system segments the gas path into two parts: the electrical equipment gas chamber and the gas density relay measurement path, connected by a controllable valve. This allows the relay to be isolated from the equipment for checking while maintaining equipment operation, with the pressure regulating mechanism independently managing the relay side pressure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system ensures reliable and efficient online monitoring of SF6 gas conditions, improving power grid reliability, reducing maintenance costs, and meeting environmental protection standards by allowing zero emission during checks.
Implementation Method 1
The pressure regulating mechanism is configured for pressure rise and fall of the gas path pressure of gas density relay, to enable the contact signal action of the gas density relay
Implementation Method 2
a gas density detection sensor, which is communicated with the gas density relay
Implementation Method 3
The online check contact signal sampling unit is connected with the gas density relay and configured to sample the contact signal of the gas density relay under the ambient temperature
Data Source
AI summary
The application provides an electrical system with online sampling and check function and its check method for high-voltage and medium-voltage electrical equipment, including electrical equipment, gas density relay, gas density sensor, valve, pressure regulating mechanism, online check contact signal sampling unit and intelligent control unit. The pressure is increased or decreased by the pressure regulating mechanism to enable the contact action of the gas density relay of electrical equipment. The contact action is transmitted to the intelligent control unit through the online check contact signal sampling unit. The intelligent control unit detects the alarm and/or blocking contact signal operating value and/or return value according to the density value of the contact action; the check of the gas density relay can be completed without maintenance personnel on site, which greatly improves the reliability of the power grid and the work efficiency, and reduces the O&M cost. At the same time, it also realizes the mutual self-inspection between gas density relay and gas density sensor, and further realizes the maintenance-free.