Insulation Fault Location for Battery Energy Storage
This solution mainly focuses on the application of IFLS-600 and SKIM1000EV in energy storage systems
Project Background
With the rapid development of new energy, the global energy storage industry has also developed rapidly in recent years, especially battery energy storage has dominated the market. The future development prospects are promising. However, the development of the industry also faces some challenges, such as safety issues. Many energy storage safety accidents have occurred. To ensure the safe operation of energy storage cabinets, battery health data must be monitored, and the battery insulation performance to the ground is a very critical data.
Battery energy storage cabinets are a special power grid system---neutral point ungrounded system referred to as IT power grid. This system is not grounded under normal circumstances. When the system's insulation performance to the ground is reduced, a grounding fault occurs in the system. The energy storage cabinet cannot work normally and fire and other safety accidents will occur. This solution is based on a battery energy storage project in China. The solution has been in operation for several years and has been used well.
Solution
In order to monitor the insulation performance of the energy storage cabinet to the ground in real time, Sikcon proposed two parallel solutions.
In the above figure, The IFLS-600 fault location system and the SKIM1000EV insulation monitor are installed.
When the battery pack supplies power to the grid(IFLS-600 starts working）
SKIM600FL continuously sends out measurement signals to monitor several battery packs in the power grid in real time. When the system insulation resistance is lower than the preset alarm value, SKIM600FL sends an alarm signal to the host computer and injects a fault location signal into the power grid. At the same time, it sends a command to the SKIF12 fault locator through RS485 communication to start capturing the signal in the CT current transformer to locate the specific battery pack fault. The device monitoring data and alarm data can be displayed centrally on the central control screen.
Application of IFLS-600 in DC grid system
When the battery pack is not supplying power（SKIM1000EV starts working）
There are several battery packs in the energy storage system. When the battery packs are fully charged, they do not need to be put into operation. The DC-side circuit breaker switch is disconnected, which will be disconnected from the power grid, causing the insulation fault location system to be unable to detect its insulation resistance. Therefore, we need to add the SKIIM1000EV insulation monitor to perform offline measurements on it. When the DC-side circuit breaker is disconnected, an auxiliary signal is fed back to the SKIIM1000EV to enable it to work and continuously measure the battery pack. Otherwise, the SKIIM1000EV exits and switches to the SKIM600FL for system insulation fault location monitoring.
