Gas Density Relay Online Calibration Using Isolated Pressure Control
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Solution Overview
Problem
The decrease in SF6 gas density and excessive moisture content in high-voltage electrical equipment can lead to insulation loss, arc extinguishing performance degradation, corrosion, and reduced surface insulation strength, posing risks to the safe operation of electrical equipment, especially in unattended substations with increasing remote monitoring requirements.
Innovation Solution
An electrical system with online sampling and calibration functions, incorporating a gas density relay, valve, pressure regulating mechanism, gas density detection sensor, and intelligent control unit, allows for isolated calibration without disrupting equipment operation, using pressure and temperature sensors to monitor and adjust gas density and moisture levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gas density relay is calibrated by isolating it from the electrical equipment and using a pressure regulating mechanism, then the calibration can be performed without affecting equipment operation and safety, but the device complexity increases due to additional components (valve, pressure regulating mechanism, intelligent control unit)
Solution Approach 1:
The system divides the gas path into two segments: one connected to the electrical equipment and another connected to the gas density relay. A valve is used to isolate these segments during calibration, allowing the relay to be calibrated independently without affecting the equipment. This segmentation enables safe online calibration while maintaining system reliability.
Solution Approach 2:
A pressure regulating mechanism acts as an intermediary between the gas source and the gas density relay during calibration. It provides controlled pressure adjustment to simulate various gas density conditions for calibration purposes, enabling accurate calibration without directly connecting to the electrical equipment. The intelligent control unit coordinates this intermediary mechanism to automate the calibration process.
2Reliability
If regular testing of SF6 gas density and moisture content is performed, then the safe operation of electrical equipment is ensured, but maintenance costs and operational interruptions increase
Solution Approach 1:
The system enables continuous online monitoring of gas density and moisture content without requiring periodic shutdowns for calibration. The gas density relay operates continuously in the background while the intelligent control unit performs automated calibration at appropriate intervals. This continuity ensures equipment safety is maintained without operational interruptions, eliminating the need to stop equipment for regular testing.
Solution Approach 2:
The intelligent control unit automatically manages the calibration process by controlling the valve and pressure regulating mechanism, eliminating the need for manual intervention. The system performs self-calibration using the existing gas path and pressure regulation capabilities, reducing maintenance requirements and operational time loss while ensuring continuous equipment safety monitoring.
3Ease of operation
If the valve is closed to isolate the gas density relay during calibration, then the calibration can proceed without affecting equipment operation, but the gas path is interrupted and requires additional control mechanisms
Solution Approach 1:
The intelligent control unit implements feedback control by monitoring the valve position and pressure regulating mechanism status during calibration. It automatically adjusts the calibration process based on real-time feedback from sensors, ensuring accurate calibration while managing the gas path interruption caused by valve closure. This feedback mechanism simplifies the overall control by automating the coordination of isolation and calibration steps.
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
Enables reliable, efficient, and environmentally friendly calibration of gas density relays, reducing maintenance costs and ensuring safe operation of electrical equipment while meeting environmental regulations.
Implementation Method 1
the pressure regulating mechanism regulates the pressure rise and fall of the gas path pressure of gas density relay, to enable a contact signal action of the gas density relay
Implementation Method 2
the gas density detection sensor comprises at least one pressure sensor and at least one temperature transducer
Implementation Method 3
the gas density detection sensor comprises at least one pressure sensor and at least one temperature transducer
Implementation Method 4
a heating element, or a refrigeration element is provided inside or outside the sealed air chamber
Implementation Method 5
a heating element, or a refrigeration element is provided inside or outside the sealed air chamber
Implementation Method 6
a piston is set in the cavity; one end of the piston is connected with a regulating rod; an outer end of the regulating rod is connected with a drive part
Implementation Method 7
the drive part is provided outside the sealed air chamber, and pushes the piston to move inside the cavity through electromagnetic force
Data Source
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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.