The BESS System: Construction, Commissioning, and O&M Guide

The Industrial and Commercial (C&I) Energy Storage: Construction, Commissioning, and O&M Guide provides a detailed overview of the processes involved in building, commissioning, and maintaining energy storage systems for industrial and commercial applications. The guide is divided into three main sections: construction and installation, commissioning, and operation & maintenance. It covers various aspects such as foundation construction, battery and inverter installation, wiring, system testing, monitoring, fault handling, and preventive maintenance.

Energy Storage Project Construction and Installation

1. Energy Storage Project Construction

A. Small Foundation Construction

Steps to Build a Small Foundation:

• Bottom concrete pouring of the foundation

• Foundation bricklaying
• Top concrete pouring for the foundation

• Demolding and foundation backfilling

• Pouring of the ground inside the foundation

B. Large Foundation Construction

C. Steel Structure Foundation

Steel structures are an alternative to concrete foundations. They offer:

• Quick installation
• Easy disassembly in the future.

2. Energy Storage Project Installation

A. Energy Storage Cabinet Lifting

• Workers usually lift the energy storage container using four lifting points located at the top corners of the container.

B. Installation Inside the Energy Storage Cabinet

1. Preparatory Work

• Tools Needed:
  • Open-end wrench or socket wrench
  • Hex wrench
  • Digital multimeter
• Batteries are pre-charged before leaving the factory. Wrap all metal installation tools with insulating tape to prevent short circuits.
• Maintain a gap between batteries during installation for good heat dissipation.
• Clarify the installation method and load-bearing conditions before starting.

2. Installation Steps

1. Inspect and inventory packaging before installation. Keep the battery installation diagram and manual handy.
2. Check the battery cabinet placement against the construction drawing. Ensure there is maintenance space and a distance of more than 0.5 meters from heat sources.
3. Follow the battery installation diagram and manual for installation.
4. Wipe dust off battery terminals and check that each bolt is tightened before installing connection bars.
5. Measure and record the open-circuit voltage of all battery modules and the total voltage of the battery cluster after installation.
6. Recheck that all connection bolts are tightened for battery reliability.
7. Power off all equipment during the installation of the high-voltage box for safety.

3. Battery Installation

• Tools for Battery Installation:
  • PACK Installation Lifting Truck

• PACK Installation Crane

4. PCS Installation

1. Disconnect all external connections of the energy storage inverter and its internal power supply.
2. Ensure the energy storage inverter is de-energized to prevent accidental energization.
3. Use a multimeter to confirm there is no electricity in the inverter.
4. Install necessary grounding and short-circuit connections.
5. Cover parts that may be live during operation with insulating cloth.

5. Wiring

1. Connect the batteries first, then connect the battery pack to the PCS.
2. Pay attention to battery polarity when wiring. Check the wiring correctness before making the first terminal connection.
3. Ensure power is off before connecting the battery cluster to the distribution cabinet. Use an insulating heat-shrinkable tube for secure terminal fit and label wires clearly. Clean up any foreign objects in the distribution cabinet.
4. Connect all metal shells within the energy storage box to form a grounding network using good conductors or dedicated grounding strips.

6. Containerized Energy Storage System Installation Complete

Before commissioning, conduct a thorough check of the equipment installation:

1. Secure all connection cables and tighten all screws.
2. Ensure the DC side voltage load meets the requirements of the energy storage inverter and that the polarity is correct.
3. Check that the AC side voltage complies with the energy storage inverter requirements.
4. Verify that all connections in the system meet relevant standards and specifications.
5. Confirm that the system is well-grounded and that the grounding resistance meets the necessary requirements before the first commissioning.

Energy Storage Project Commissioning

1. Single Energy Storage Cabinet Commissioning for Small Projects

Power Cable Handover Test

The power cable handover test should meet the following requirements:

• Check the phase (polarity) at both ends of the cable.
• Measure insulation resistance.
• Perform the main insulation DC withstand voltage test and leakage current measurement.
• Conduct AC withstand voltage testing.

Grounding Grid Handover Test

Before conducting the grounding grid handover test, ensure these conditions are met:

• The grounding grid construction is complete.
• Soil humidity is suitable; measurements should not occur after rain. Clear weather is needed for three days.

The grounding grid handover test should include:

• Measurement of the grounding impedance.
• Grounding integrity test.

Energy Storage Battery Management System (BMS) Handover Test

The BMS single commissioning should meet the following requirements:

• BMS collects the battery voltage in real-time.
• BCU collects the terminal voltage of the battery pack in real-time.
• When BMU connects to a temperature sensor, it collects and uploads real-time temperature data to BAU via the CAN bus.
• When BCU connects to a shunt, it collects and uploads real-time charging and discharging currents to BAU via the CAN bus.
• BMU calculates the SOC value of each battery in real-time and uploads it to BAU via the CAN bus.
• BMU balances the batteries actively to maintain consistency.
• BMU and BCU output various alarm signals to ensure safe operation.

2. System Commissioning

Before commissioning the energy storage power cabinet system, ensure these conditions are met:

• All primary and secondary equipment has completed the handover test with qualified data.
• The energy storage inverter (PCS), battery management system (BMS), and energy management system (EMS) have powered up and completed single commissioning.

Communication Commissioning

• BMS should communicate with PCS to send battery pack information and protection alarm signals.
• PCS should communicate with EMS to send battery pack data. Ensure all individual battery voltages, temperatures, SOC, and pack voltage and current information display correctly.

3. Large-Scale Energy Storage Commissioning

Basic Requirements

1. The energy storage power cabinet commissioning should include:
   • Subsystem commissioning.
   • power cabinet joint commissioning.
2. Develop a commissioning outline, plan, and emergency plan.
3. Dispatching agency approval is required for the commissioning plan.
4. Follow the “Safety Regulations for Electrochemical Energy Storage Power Cabinets.”
5. Commissioning personnel must be familiar with:
   • Equipment working principles and structures.
   • Commissioning processes and quality standards.
   • Safety work regulations.
   • Machinery, electricity, testing, and safety protection.
6. Inspect tools and instruments to ensure they are qualified and within the validity period.
7. Maintain complete commissioning records and prepare a commissioning report.

On-Site Commissioning Items

• Insulation resistance test
• Cooling system commissioning
• Battery management system commissioning
• Energy storage inverter commissioning
• Energy storage coordinator commissioning
• Monitoring system commissioning
• Relay protection and safety automatic device commissioning
• Communication and dispatching automation system commissioning
• Whole power cabinet system joint commissioning

Energy Storage Project O&M

1. Operation Monitoring

• Operating personnel monitor the energy storage system’s operational status, ensuring remote signaling and measurement are normal.
• Monitor AC and DC side voltage, current, active power, reactive power, and alarms.
• Check battery management system data for voltage, current, SOC, power, temperature, and alarms.
• Conduct routine checks on the fire alarm and extinguishing systems.
• Maintain operation records of daily monitoring and inspection items.

2. Patrol Inspection

• The patrol inspection team divides work into daily, regular, and special inspections.
• Daily patrol inspections are conducted from a distance and documented.
• Regular on-site patrol inspections follow a fixed cycle.
• Special inspections occur after severe weather or significant defects.
• High-voltage electrical equipment inspections follow DL/T 969 guidelines.
• Secondary equipment inspections also follow DL/T 969 guidelines.
• Form work records for archiving.

3. Abnormal Operation and Fault Handling

Energy Storage Inverter

• Stop the inverter immediately for inspection if abnormalities occur.
• Inspect if abnormal noises or key component issues arise.
• Stop for inspection if the temperature exceeds the specified value.
• Inspect for malfunctions in the control system.
• Inspect power components if power output is abnormal.
• Stop for inspection if the cooling device shows abnormalities.
• Address cable head faults or overheating issues.

Battery System

• Stop for inspection if experiencing over-discharge, over-charge, or short circuits.
• Perform equalization charging if voltage is too low or high.
• Stop for inspection if abnormal conditions arise, such as odor or bulging.
• Evacuate personnel if smoke or fire occurs and follow emergency procedures.

Battery Management System

• Check for loose connections if communication failures occur.
• Stop for inspection if alarms cannot be reset.
• Inspect the battery management system’s host and power modules for operational failures.

4. Remote Monitoring and Intelligent O&M

The intelligent O&M of the energy storage power cabinet is often managed through the “Smart Energy Storage Cloud Platform.”

1. The platform connects global energy storage projects for intelligent O&M. It allows monitoring of project operations and battery performance.
2. The platform gathers data to maximize its value, aiding in optimizing designs and extending service life.

Operation and Maintenance

• The maintenance team should have the necessary tools and conduct regular checks.
• Maintain a spare parts library for consumable parts.
• Create records after maintenance and document defective equipment.
• The maintenance cycle for equipment is typically one month.
• Regularly check grounding and lightning protection systems.
• Test fire detection and extinguishing systems regularly.
• Check communication equipment and remote control systems for normal operation.

Maintenance Items

• Clean the energy storage inverter and battery cabinet.
• Measure wind speed of the cooling fan and inspect rotation.
• Add refrigerant to the cooling system and check for leaks.
• Measure current in related circuits of the energy storage inverter.
• Replace components prone to damage.
• Clean and tighten battery connections.
• Track operating temperature of the battery.
• Process balance of battery modules and clusters.
• Replace batteries with abnormal voltage and capacity.
• Measure voltage of the emergency power supply.
• Calibrate SOC parameters of the battery management system.
• Test charging and discharging times of the energy storage unit.

Conclusion

The C&I Energy Storage: Construction, Commissioning, and O&M Guide is a valuable resource. It is for those deploying and managing energy storage systems. By following this guide’s rules, stakeholders can ensure the safe, efficient, and reliable operation of their energy storage assets. To optimize performance and extend component life, monitor and maintain the equipment according to safety protocols on a regular schedule. As the energy storage industry grows, staying current on the latest construction, commissioning, and O&M practices will be key to success.

FAQ