This article will provide you with the necessary steps to maintain your capacitor bank.
Maintenance with Capacitor Bank Disconnected
Basic Monthly Maintenance Procedure:
1. Visually inspect capacitors.
2. Check the fuse protection.
3. Control ambient temperature (average 35°C in accordance with IEC 60831).
4. Control the service voltage, especially during low loads (it must not exceed nominal +10%).
Basic Bi-Annual Maintenance Procedure:
1. Keep the capacitor terminals as clean as possible.
2. Verify the condition of the contact points of the operating elements.
3. Check to ensure that the capacitor’s current is neither lower nor higher than 120% by phase and that it is balanced.
Basic Annual Maintenance Procedure:
1. Apply 2.5 kV between the capacitor terminals and the earth for one second to perform a dielectric stiffness test.
2. At each step, check the capacitance.
3. Verify that the consumption of alcohol is manual; this can be an indirect way to verify.
4. Ensure that all terminal connections are tight.
5. Check the fuse:
– Power Circuit NH Fuses: Check continuity and temperature.
– Power Circuit: Check continuity and temperature on the three-pole breaker or four-pole breaker.
– Control circuit: Check continuity and temperature on the two-pole circuit breakers.
6. Inspection of Contactors: Key Points
– Check to make sure that there are no signs of burnt or hardened plastic.
– Ensure the head is properly inserted.
– As shown in the table above, check the tightness of the cables and terminals.
– Terminals must be cleaned.
– Check that the RD discharge resistors are in good shape (not burned or open).
7. Cleaning the contactors is necessary in dirty environments (dust particles, sawdust particles, rust particles, etc.). Vacuum the contactors periodically. Cleaning the capacitor bank depends on how much dirt is in the bank.
Important Points for Regulators Inspecting:
– Check to make sure the regulator is not showing signs of wear, and that the display is working normally.
– Check the cables and terminals. They should be clean, not hardened or heated.
– Check the connections, and insert the removable power strips.
– Power strips must be securely fastened to removable regulators.
– Ensure that the terminals have been tightened correctly (recommended torque: 0.6 Nm).
– Cleaning the Cabinet:
– Remove all metallic and non-metallic debris.
– Cleaning the inside of your cabinet is important.
– Cleaning ventilation grilles is important.
Maintenance with Capacitor Bank Connected
Cleaning the Cabinet:
– Make sure that you can turn on and off the main switch without forcing the mechanism.
– Test the earth leakage protection on the capacitor bank by pressing the test button.
– Verify that the voltage of the auxiliary control is within tolerance limits.
– Check that the autotransformer is in good shape and does not show any signs of degradation.
– Manually connect and disconnect the capacitors. Refer to the manual of the regulator before performing these actions and make the following checks:
– Verify that the contractors are connected and disconnected properly.
– Once connected, make sure the contactor does not rumble or vibrate.
– Check the consumption of capacitors in each phase.
Note: If the consumption is less than the table and the voltage falls within the tolerance ranges, it is a sign that the capacitors are degrading. This should be checked on any capacitor and replaced with another one.
This post was written by Justin Tidd, Director at Swartz Engineering. For nearly half a century, Swartz Engineering has been at the forefront of industry safety. They are a family-owned company specializing in power distribution for the electrical industry. Our design ensures maximum flexibility for excellent reliability and a high return on investment.