Why should you worry about your capacitors?
CONDIS® high voltage capacitors are installed in or nearby high voltage switchgears and instrument transformers, in nearly every substation all over the world. These are key elements for a safe and well performing electrical network. In the rare case of a capacitor failure, the surrounding (and often expensive) equipment may suffer severe damage.
To guarantee the reliability of our components, we suggest a regular maintenance plan and offer services accordingly. This allows you to avoid unexpected outages, manage your risks and forecast your expenses.
A capacitor’s lifecycle
What can be done by you (on-site)?
- Measure the capacitor’s temperature by infrared thermal radiation. Basic approach of monitoring. Helps to quickly control the capacitor’s behavior showing its general condition.
- Visual inspection
Frequency: Every time you assess your substation equipment.
- Measure the capacitance and the tangent delta at 10 kV. Contact our services department for an offer to interpret the measured values.
- Cleaning. Deposits (i.e. pollution) degrade a capacitor’s performance.
Frequency: Whenever the associated circuit breaker’s maintenance is performed.
What can CONDIS do for you (off-site)?
Provide us with your capacitance and tangent delta measurements, your capacitor type, serial number and other data (request our check-list email@example.com) and we can offer our services to process the results and advise on the capacitor’s condition.
Testing in a high voltage laboratory
The routine test is the most accurate way to assess a capacitor’s condition and prevent potential failures. The test needs to be conducted in a high voltage laboratory.
Frequency: We recommend thorough testing approx. every 20 years. See CONDIS’ HV Capacitors Life Cycle Policy for details. The frequency is subject to a capacitor’s application. Each case is evaluated individually.
Repairs & recalibration
Depending on the results of the above mentioned tests and activities, we can proceed to repair or replace spare parts and recalibrate the capacitor.
What can happen if I don’t worry about my capacitors?
- Damaged isolator
Cracked or damaged sheds on the isolator or damages to the isolator itself will modify the creepage distance and thereby increase the risk of flashover.
- Dielectric Breakdown
The dielectric’s ageing is a chemical process. This can destroy molecule connections which may reduce the dielectric’s voltage behavior.
- Corrosion & Leaks
The dielectric fluid undergoes temperature variations which alter a capacitor’s internal pressure. Should this cause leakage, it may accelerate the dielectric’s ageing process and miscellaneous elements may modify its voltage behavior.
Source: CIGRE TB368
However, despite the above arguments, as capacitors are and remain passive elements, regardless of their state, these never represent a danger.
For more information about CONDIS’ product lifecycle policy and advisory services, do not hesitate to get in touch with us now.
We would love to hear from you!