Capacitor Bank Testing Service

Capacitor Banks consists of tuning reactors, capacitors and inrush limiting reactors. To lower the electricity bill and to decrease shortfalls in the distribution system, power factor correction units or capacitor banks are added to counterbalance as much of the magnetizing current as possible. Capacitors in most power factor correction unit draw current that leads the voltage, thus giving a leading power factor.

Capacitor bank tests requires test instrument within calibration date, tagged and tested. Insulation resistance tester, Capacitance Bridge, multimeter, three phase balanced voltage source, high speed recorder and single phase current source.

Why is Capacitance Bank Test Necessary?

Capacitors banks performs a vital role in giving your power system proper power factor correction. Power Factor Correction unit have different operating environments dependent on the place they are installed. Moisture, harmonics, temperature and time affects the power factor correcting ability of capacitor banks. Already installed capacitor banks, if not tested or unmaintained within specific time period, becomes incapable of functioning at their finest levels. With time, the operation of capacitors can weaken, decreasing the power factor of your power system, resulting in power factor loss.

Carelabs provides you with comprehensive capacitor maintenance services, making sure that your capacitor banks is functioning to the best of its capacities. Carelabs offers testing for a variety of capacitors, comprising fixed capacitor banks and automatic capacitor banks

What is Done During Capacitor Bank Testing?

There are 3 types of tests in the testing plan. They are:

Routine test:

• Visual examination
• Sealing test at 800C + 50C for 3 Hours.
• Test for output and capacitance.
• Insulation resistance test.
• Voltage test between terminals:
• Voltage test between terminals and container:
• Voltage test between terminals and container for capacitor banks
• Test for efficacy of discharge device:
• Measurement of tangent of dielectric loss angle (tan) :

Type test:

• High Voltage Impulse Withstand Test.
• Bushing Test.
• Thermal Stability Test.
• Radio Influence Voltage (RIV) Test.
• Voltage Decay Test.
• Short Circuit Discharge Test.

Pre commissioning or Installation Test of Capacitor Bank:

• Capacitor bank when introduced at site, should undergo some explicit tests to make sure that the connection of the bank and each unit are in proper sequence and according to specified standards.

How is Capacitor Bank Test Performed?

Site Risk Assessment

• Before performing the tests, any danger or hazards associated with the tasks at the worksite should be recognised and assessed with suitable control measures employed and documented. If any risks cannot be managed or reduced to an acceptable level, do not proceed with the task and seek assistance.
• All the tasks must be performed with capacitor bank de-energised and proper control measures in place to avoid unintended contact with live plant or penetrating exclusion regions.
• After the assessment issue a test Permit

Carry out Secondary Isolation

• Evaluate the requirement to carry out secondary isolation of the protection systems associated with the capacitor bank.
• Factors like sensitivity of capacitor bank protection and the potential for a capacitor under test should be considered to involuntarily discharge stored power into a protection system.

Record plant details and identification details of each capacitor unit:

• Manufacturer’s name
• Manufacturer’s type description
• Manufacturer’s serial number
• Year of Manufacture
• Rated Capacitance Cn and measured capacitance as stamped on the nameplate
• Serial number of each capacitor can
• Rated Output Qn
• Rated Voltage Un
• Rated Current In
• Temperature Category
• Dielectric Fluid Record identification details of any inrush limiting or tuning reactor

Visual Inspection of Capacitor Bank Condition

• Inspect the external surfaces and ensure the capacitor units and reactors are clean and dry.
• Check that primary connections are correct.
• Check earthing to capacitor bank mounting frames and enclosure.

Measure Insulation Resistance

• Insulation resistance tests are to be applied for one-minute duration each.
• Where several components are connected in parallel, for example capacitor cans, it is not necessary to obtain a separate insulation resistance measurement of each component.
• To make sure that the capacitors being measured have charged enough to permit precise insulation resistance calculation make sure that the capacitor has been charged by the tester such that there is no more than a 5.0% change in insulation resistance over a 1 minute time period.

Measure Capacitance

• Measure the capacitance of each individual capacitor unit using a capacitance bridge.
• It is advised not to detach capacitor units for measurement so as to elude involuntary damage to the cap.