The PCS (Energy Storage Converter) in the energy storage system is an extremely critical device that is responsible for converting and controlling electrical energy to achieve storage and release of electrical energy. During the actual operation of the energy storage system, PCS may encounter various fault problems. The following are common troubleshooting issues and solutions for PCS in energy storage systems, as well as corresponding operating steps:
1、 Equipment bus overvoltage and undervoltage
Problem description: The inverter bus may experience overvoltage or undervoltage, which is usually due to the low voltage of the battery stack.
resolvent:
1. Check the voltage of the battery pack:
. Use a voltmeter to measure the voltage of the battery pack and confirm if it is below the normal operating range.
. If it is caused by accidental discharge, wait for the battery voltage to return to the normal range before attempting to power on again.
2. Check the undervoltage protection parameter settings of the inverter:
. Enter the inverter settings interface and check the set values of the undervoltage protection parameters.
. If improper parameter settings are found, it is necessary to contact the equipment manufacturer or professional technicians for modification.
Operation steps:
1. Disconnect the power supply of PCS to ensure the safety of operators.
2. Use a multimeter or voltmeter to measure the voltage of the battery pack.
If the voltage is below the normal range, take charging measures or wait for it to naturally recover.
Before restarting PCS, check and confirm that the undervoltage protection parameters are set correctly.
2、 Insulation failure
Problem description: The inverter may experience insulation faults, which are usually caused by abnormal operation of the insulation detector or loose wiring.
resolvent:
1. Check the insulation tester:
. Confirm whether the insulation tester is in normal working condition.
. Check if the wiring of the detector is secure, free from looseness or short circuits.
2. Check the wiring:
. Check the internal and external connection wires of the inverter one by one, especially whether the insulation layer of the power line and high-voltage line is intact.
. Use an insulation tester to test the insulation resistance of each section of the circuit to ensure compliance with standard requirements.
3. Tighten or replace wiring:
. If loose wiring or insulation damage is found, it should be tightened or replaced in a timely manner.
Operation steps:
1. Disconnect the power supply of PCS and hang a warning sign that reads' Do not close '.
2. Check the insulation tester and wiring condition one by one, and use tools such as screwdrivers, insulation testers, etc. to perform necessary tightening and testing.
If the insulation layer is damaged or the wiring is loose, repair or replace it according to the specifications.
After the repair is completed, restart PCS and observe if there are still insulation faults.

3、Phase frequency fault

Problem description: The inverter may experience phase frequency faults, usually due to abnormal three-phase voltage sources.
Solution: Check if the three-phase voltage source is stable and if there are any abnormal fluctuations.
Operation steps:
1. Measure the voltage value of a three-phase voltage source using a voltmeter.
2. Check if the voltage source is stable. If there are any abnormal fluctuations, contact maintenance personnel for handling.
4、 AC/DC circuit breaker failure
Problem description: AC and DC circuit breakers have malfunctioned, which may cause them to malfunction.
Solution: Check if the circuit breaker is in the closed state and verify its working status.
Operation steps:
1. Observe the indicator light or display screen of the circuit breaker to confirm if it is closed.
2. If it is not closed, try manually closing it. If it cannot be resolved, contact maintenance personnel for assistance.
5、 The combiner cabinet is closed, but the inverter cannot be turned on
Problem description: When the combiner cabinet has been closed but the inverter still cannot be turned on, the program judgment of the battery management system (BMS) should be checked.
Solution: Confirm that the BMS needs to close a certain number of battery clusters to enable the inverter to start up normally.
Operation steps:
1. Check the settings and status of BMS.
2. Ensure that the number of closed battery clusters meets the BMS startup requirements.
6、Communication failure between upper and lower computers
Problem description: Communication failure may occur between the upper and lower computers of the inverter.
resolvent:
1. Check if there is a conflict in the IP address of the touch screen.
2. Check if there are any conflicts between PCS and ARM addresses.
3. Check if the network connection between the touch screen and the control board is normal.
Operation steps:
1. Log in to the management interface of the relevant device and check the IP address and address allocation.
2. Check and adjust conflicting addresses.
3. Check and repair network cable connection issues.
7、 The touch screen can light up when powered separately, but it remains unlit during operation
Problem description: The touch screen may light up when powered separately, but it may not light up continuously during operation.
Solution: Check if the DC side of the inverter is supplied with DC power before the touch screen can work.
Operation steps:
1. Use a multimeter to check the voltage output on the DC side.
2. Check if the UPS is turned on and working properly.
3. If there is no DC output or UPS failure, the relevant equipment needs to be repaired or replaced.
For common faults in PCS in energy storage systems, operators need to have sufficient knowledge and operational skills in electricity. When dealing with faults, one should follow the operating steps to troubleshoot and solve problems one by one. Pay attention to safety first, strictly follow the operating procedures to ensure the safety of equipment and personnel. At the same time, it is recommended to conduct regular inspections, troubleshooting, and timely handling of PCS, which can reduce the occurrence of PCS failures.