The maximum allowable input leakage current of UPS products can reach up to 5% of the UPS rated load current, which is significantly higher than the common 30mA configuration. Consequently, the operating current level must be increased when selecting an anti-leakage protector to prevent frequent misoperation. According to power department regulations, UPS leakage protection should be classified as first-level general protection and is considered a type of leakage protection.
When there are multiple leakage protectors in a power distribution system, the selectivity of grading actions must be maintained. The rated leakage current of the upper-level leakage protector should be at least three times the rated leakage current of the lower-level leakage protector. Additionally, the minimum non-operation time of the upper-level leakage protector should be greater than the maximum cut-off time of the lower-level protector. Failure to properly match the upper and lower actions may result in large-scale power outages.
To address these requirements, residual current transducers are designed to meet the needs of multi-level residual current protection. These transducers offer a range from 0.01A to 10A, ensuring high accuracy and linearity, low zero offset voltage, high bandwidth, and short dynamic response times. By incorporating these advanced transducers, power distribution systems can achieve effective and reliable leakage protection, reducing the risk of misoperations and large-scale power failures.