Overview
IEC 62146-2:2023 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies requirements for transient recovery voltage (TRV) capacitors used in high-voltage alternating current (AC) circuit-breakers. Applicable to rated voltages above 100 kV and frequencies of 50 Hz or 60 Hz, this standard addresses capacitors installed phase to earth, either in parallel to the bushing on dead tank circuit-breakers, immersed inside the circuit-breaker, or freestanding nearby. The primary function of TRV capacitors defined by IEC 62146-2:2023 is to mitigate transient recovery voltage and control the rate of rise of recovery voltage (RRRV), thereby enhancing the performance and safety of high-voltage circuit-breakers.
This document provides uniform rules for the design, testing, rating, safety, installation, operation, and maintenance of TRV capacitors used on both air insulated switchgear (AIS) and gas insulated switchgear (GIS). It excludes grading capacitors specified under IEC 62146-1 and capacitors not directly associated with high-voltage AC circuit-breakers.
Key Topics
- Scope and Application: Covers TRV capacitors for circuit-breakers with rated voltages above 100 kV at 50 or 60 Hz, installed in multiple configurations including dead tank and live tank circuit-breakers.
- Design and Construction: Details on capacitance tolerances, capacitor loss, partial discharge levels, mounting angles, mechanical bending load resistance, and impregnation medium requirements.
- Testing Procedures: Includes electrical type tests such as switching impulse voltage, lightning impulse, power frequency voltage tests, partial discharge measurements, mechanical bending, tightness, vibration, and short-circuit discharge tests. These tests ensure reliability under operational conditions.
- Service Conditions and Ratings: Specifies rated voltage, insulation levels, rated frequency, and environmental service conditions for TRV capacitors used in high-voltage circuit-breakers.
- Safety Requirements: Addresses safety precautions by manufacturers and users, with clear guidelines to minimize risks during transportation, installation, operation, and maintenance.
- Marking and Identification: Ensures proper labeling for traceability and easy identification of capacitors, enhancing asset management and compliance.
- Environmental Considerations: Guidelines for environmental aspects related to the lifecycle of TRV capacitors including storage and disposal.
Applications
IEC 62146-2:2023 TRV capacitors are critical components in the electrical power industry, specifically in the domain of high-voltage AC circuit-breakers. Their practical applications include:
- Dead Tank Circuit-Breakers: Installed phase-to-earth in parallel to bushings to limit transient recovery voltages after breaker operation.
- Live Tank Circuit-Breakers: TRV capacitors used internally or mounted externally to withstand and mitigate transient electrical stresses.
- Gas Insulated Switchgear (GIS): Used within GIS circuit-breakers to improve switching performance and prevent insulation failure from voltage spikes.
- Air Insulated Switchgear (AIS): Positioned on or near AIS circuit-breakers to ensure stable switching and reduce transient overvoltages.
- High-Voltage Transmission Systems: Helping secure grid reliability by controlling transient voltages during switching operations and faults.
- Power Utility Maintenance and Safety: Enabling safer operation, easier maintenance, and compliance with international safety standards through standardized capacitor specifications.
Related Standards
To ensure comprehensive compliance and interoperability, IEC 62146-2:2023 should be used alongside the following related standards:
- IEC 62146-1:2013 and its amendment IEC 62146-1:2013/AMD1:2016 - Specifications for grading capacitors and general capacitor requirements for high-voltage AC circuit-breakers.
- IEC 62271 Series: Including IEC 62271-1 (General requirements for high-voltage switchgear and controlgear), IEC 62271-100 (High-voltage circuit-breakers), and IEC 62271-203 (Gas-insulated metal-enclosed switchgear and controlgear).
- IEC 61462 and IEC 62155: Standards governing insulator design for capacitors, including composite and ceramic housings.
- ISO/IEC Directives Part 1 and Part 2: For the development and formatting of international standards.
These related standards form the framework for high-voltage circuit-breaker components, ensuring that TRV capacitors meet rigorous safety, performance, and compatibility criteria globally.
By adhering to IEC 62146-2:2023, manufacturers, utilities, and maintenance personnel can ensure that TRV capacitors used in high-voltage AC circuit-breakers are designed and tested to withstand critical operational stresses, thereby improving the reliability and longevity of electrical power infrastructure. This standard supports enhanced grid stability, improved safety, and efficient asset management in modern electrical networks.