What is the required grounding resistance for the PCS cabinet in an energy storage system?

The grounding resistance requirement for PCS cabinets is not a fixed value, but rather depends on relevant safety and EMC standards and system design objectives. From a safety perspective (such as IEC 62109), the resistance of the protective grounding conductor must be low enough to ensure rapid triggering of protective devices in the event of a fault; typically, it must be less than 0.1Ω. From an EMC perspective, low grounding resistance helps reduce the impedance of the grounding system, providing a good discharge path for common-mode noise currents and surge currents, and reducing ground potential rise and interference. In practical engineering, the lowest possible grounding resistance is generally desired; for example, the resistance from the cabinet grounding busbar to the earth grounding electrode should be less than 1Ω or 4Ω (depending on site conditions). Simultaneously, the connection resistance between internal components and the grounding busbar should also be minimized, typically achieved through short, thick copper busbars and good overlap.