Capacitor Bank Testing: Importance and Procedures Explained
A collection of capacitors of comparable ratings is known as a capacitor bank. These capacitors are arranged in parallel or series sequence to gather electrical energy. A capacitor bank is usually applied to an AC source of power. This helps to rectify or compensate for power factor lag or phase shift. These banks can also be connected to a DC power supply. This helps increase the comprehensive quantity of the power supply’s ripple current capacity or the stored energy. The primary use of a capacitor bank is to collect and store electrical energy to meet the operational requirements while ensuring the required power factor levels for the electrical equipment.
Now the question arises: what is the need for testing these banks, and how to test a capacitor bank. If you are curious to know the answers to the same, continue reading. This blog will list all the different types of tests conducted on capacitor banks, their importance, and their procedures.
What is the Role of Capacitor Bank Testing?
The significance of capacitor banks in a power system can never be neglected as they play a crucial role in controlling the power factor correction. The power factor correction units perform various functions based on their location in the system. The power factor correction of capacitor banks changes due to moisture, temperature, time, and harmonics. To perform their best, the installed capacitor banks must be tested regularly and maintained to the highest quality.
Although capacitor banks of the finest qualities function quite well, their operation can weaken with time. This results in a decrease in the power factor of your system. Eventually, this leads to power factor loss. Therefore, it is essential to regularly test the capacitor bank and ensure its reliability and performance.
A capacitor bank is static equipment. It must be examined at regular intervals to ensure proper maintenance. If they are not tested or maintained regularly, they can pose serious hazards to the industry.
What are the Different Types of Capacitor Bank Tests?
Testing capacitor banks is not a brief process. It involves several types of tests. A professional technician tests a bank based on its type and requirements. Below are the different types of capacitor bank tests.
- Design Tests or Type Tests of Capacitor Bank
- High Voltage Impulse Withstand Test.
- Bushing Test.
- Thermal Stability Test.
- Radio Influence Voltage (RIV) Test.
- Voltage Decay Test.
- Short Circuit Discharge Test.
- Routine Test of Capacitor Bank
- Short Time Over Voltage Test
- Terminal to Case Voltage Test
- Capacitance Test
- Leakage Test of Capacitor Units
- Discharge Resistor Test
- Loss Determination Test
- Fuse Capability Test of Internal Fused Capacitor Unit
- Pre-commissioning or Installation Test of Capacitor Bank
- Capacitance Measurement
- High Voltage Insulation Test
The type tests performed on capacitor banks are–
How to Perform the Capacitor Bank Testing?
How to test the capacitor bank? It's a thorough process requiring several different steps. You need to have expert knowledge and practice to carry out the capacitor bank testing. Therefore, it is always suggested that you leave this to a professional. Below is the step-by-step procedure for capacitor bank testing.
- Carry Out an On-Site Risk Assessment
- All tests must be done with Capacitor Bank De-energized
- Contact with high voltage at capacitor bank primary connections
- Extreme fault current
- Stored energy in charged capacitors
- Carry Out Secondary Isolation
- Record Plant Details
Record details of each capacitor unit
- Manufacturer’s name
- Manufacturer’s type description
- Manufacturer’s serial number
- Year of Manufacture
- Measured Capacitance
- Rated Capacitance as marked on the nameplate
- The serial number of each capacitor can
- Rated Output Qn
- Rated Voltage Un
- Rated Current In
- Temperature Category
- Visual Inspection of Capacitor Bank Condition
- Measure Insulation Resistance
- Measure Capacitance
- Measure Reactance
- Carry Out High Voltage Test
- Check the Balancing of Each Bank
- Carry Out Primary Injection
- Complete Pre-commissioning Checklist
- Check if sheet metal work is free from transport damage
- Check if sheet metal work is assembled correctly
- Check that all fixed panels are bolted in their position
- Check if all door fittings are tight
- Check if door locks operate optimally
- Check if the overall appearance and clean paintwork
- Check if all correctness and tightness of control cable terminations
- Check if capacitors are neat and free from breaks or leaks
- Check if busbar connections are correctly torqued
- Check if capacitor bushing connections are correctly torqued correctly
- Check the operation of the earth switch
- Check the operation of the isolator
- Check the operation of discharge timers and electrical interlocking
- Check the operation of point-on wave relays
- Energize and Carry Out on Load Tests
Benefits of Capacitor Bank Testing
As you are now aware of the basic steps on how to check 3 phase capacitor banks, you must know about the benefits of this testing.
- Decreases system’s line current
- Enhances load’s voltage level
- Minimises system losses
- Enhances source current’s power factor
- Reduces alternator’s load
- Reduces load’s capital investment per megawatt
- Decreases electricity bill
Read More: EXPLAINING POWER FACTOR CORRECTION AND ITS IMPORTANCE
Summing Up
Using electrical systems is crucial and quite helpful in industrial units. One such component is the capacitor bank. However, to maintain its efficiency, it is essential to get them tested regularly. Reading above must have introduced you to the detailed process of how to test capacitor banks. But do not do it yourself unless you are trained for it. Always rely on experts for this. Also, if you are looking for the highest quality capacitor banks, shop from the e-shop of Schneider Electric to relish the convenience and high-quality products at the same time.
Frequently Asked Questions
Q1. What is a capacitor bank?
Ans: A capacitor bank is a collection of different capacitors arranged in series or parallel to collect and store electrical energy for an electrical system.
Q2. What is capacitor bank testing?
Ans: Testing the efficiency and functioning of capacitor banks is known as capacitor bank testing. It involves various types of tests to identify faults in the banks’ functioning.
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