Over-voltage protection relay PCS-978S

under-voltageover-currentdifferential

PCS-978S has been designed specifically for the protection of various type power transformers, including two-winding transformers, three-winding transformers (up to 6 branches), as well as auto-transformers in any voltage level. PCS-978S is the main protection for the transformer and contains many other protection, control and monitoring functions. With its modular structure, flexibility and the powerful PCS-Studio engineering tool, PCS-978S offers future-oriented system solutions with high investment security and low operating costs. • Transformer differential protection (87T) • Inrush blocking • CT saturation blocking • Overexcitation blocking • CT circuit failure blocking • Amplitude compensation • Phase angle compensation • Restricted earth-fault protection (64REF) • Winding differential protection (87W) • Overexcitation protection (24) • Mechanical protection (MR) • Phase overcurrent protection (67P, 50/51P) • Earth-fault protection (67G, 50/51G) • Negative-sequence overcurrent protection (67Q, 50/51Q) • Undervoltage protection (27P) • Overvoltage protection (59P) • Zero-sequence overvoltage protection (59G) • Switch-onto-fault (SOTF) logic • Remote/local control • Voltage and current drift auto adjustment • Frequency tracking