High-Voltage Intelligent Switch AC Capacitor for Grid Reactive Power
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Solution Overview
Problem
Existing high-voltage capacitor systems for reactive power compensation in power grids face issues with high power consumption, high cost, and poor connection between capacitors and switches, leading to inefficiencies and safety concerns, particularly due to the need for external detection and protection devices and the limitations of thin film metalized capacitors in high-voltage applications.
Innovation Solution
A high-voltage intelligent switch AC capacitor system that integrates a high-voltage intelligent switch with the capacitor, featuring a series connection of intelligent switch capacitor units, a control module, and built-in protection measures, which includes temperature, current, and voltage detection, and a discharging module to prevent overheating, overcurrent, and overvoltage, reducing power consumption and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a vacuum circuit breaker is used for capacitor fling-cut switching, then the switching operation can be performed, but inrush current occurs during switching
Solution Approach 1:
A high-voltage intelligent switch is introduced as an intermediary device between the power grid and the capacitor. This switch incorporates a control module that detects voltage and current parameters, and a discharging module that provides a controlled discharge path, thereby eliminating inrush current during capacitor switching operations while maintaining ease of operation
2Object-generated harmful factors
If a thyristor fling-cut switch is used to avoid inrush current, then inrush current is avoided, but power consumption and cost increase
Solution Approach 1:
The patent employs a high-voltage intelligent switch with a discharging module that uses inexpensive resistive discharge elements instead of expensive thyristor-based solutions. The switch operates for short durations during capacitor switching events, allowing the use of simpler, lower-cost components that consume less power while achieving the same protective function
3Reliability
If detection and protection devices are installed externally for capacitor security, then protection coverage is provided, but the system complexity and cost increase
Solution Approach 1:
The patent integrates detection and protection functions directly into the high-voltage intelligent switch. The control module within the switch incorporates voltage detection, current detection, and control logic, merging what would traditionally be separate external devices into a single integrated unit, thereby maintaining comprehensive protection coverage while reducing system complexity and component count
4Ease of manufacture
If thin film metalized capacitor core packages are used in high-voltage applications, then cost is reduced, but capacity decay accelerates due to partial pressure increase
Solution Approach 1:
The patent addresses the capacity decay issue by implementing a control module that actively monitors voltage distribution across series-connected capacitor core packages. When imbalances are detected that could lead to accelerated decay, the system adjusts operating parameters or redistributes voltage loads, allowing the use of cost-effective thin film metalized capacitors while extending their operational life through active parameter management
Data Source
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AI summary
Disclosed is a high-voltage AC capacitor for reactive power compensation of 10kV-35kV power grid, and in particular to a high-voltage AC capacitor with a high-voltage switching switch provided therein, as well as a structure for prolonging the service life of a thin film metalized high-voltage capacitor and a control method for prolonging the service life of the thin film metalized high-voltage capacitor. The AC capacitor is formed by multiple intelligent switch capacitor units connected in series, and each capacitor unit is formed by a switch contact (K11-Kn1) and a capacitor (C1-Cn) connected in series. If there are N capacitor units, when each switch contact is disconnected, the endurable voltage of each switch contact, the endurable voltage between the switch contact and a coil and the voltage each capacitor withstands are 1/Nth of the total voltage; when the switch operates, all the contacts operate at the same instant, the switch contacts are prevented from striking sparks or discharging arcs under the protection of the contact protection circuits, and the high-voltage switch is realized through multiple air contact switches connected in series.