PCS S Series
3Pages

PCS-931S Line Differential Relay PCS-931S line differential relay integrates main and back-up protection functions, which is designed for overhead line, cables and hybrid transmission lines of various voltage levels and provides comprehensive protection and control solutions. With its flexibility and the powerful PCS-Studio configuration tool, PCS-931S offers future-oriented system solutions with high investment security and low operating costs. Busbar Line Features • Two-terminal transmission line application, including overhead line and cable, support steady-state and transient capacitive current compensation • Differential Protection ° Phase-segregated differential protection employs DPFC and steady quantities as protection criteria, easy to set, quick to clear the fault, high sensitivity and immune to power swing and load fluctuation. ° Self-adaptive floating threshold which only reflects deviation of power frequency components improves the sensitivity and reliability during load fluctuation and system disturbance. ° Current differential protection adopts three-segment philosophy, each slope can be set by user. ° Current differential protection has the excellent resistance to CT saturation when external fault. As long as the correct transfer time is no less than 3ms, current differential protection will ensure fast clearance of internal fault and non-operation of external fault. ° Innovative dynamic capacitive current compensation is introduced to the device, in order to compensate both steady-state capacitive current and transient capacitive current, which can increases the sensitivity to high-impedance faults in long distance transmission lines. ° Current differential protection supports double fiber channel, parallel and independent, either can be selected as main channel and seamlessly switched to standby channel when main channel is abnormal. ° Unique and reliable differential logic and it can be set non-operation when CT circuit failure under normal conditions. Distance Protection ° Distance protection adopted the half-wave algorithm is also supported, and its typical operation time is 12-15ms. ° 6 zones distance protection, independent zero-sequence compensation factor for each zone, the phase-to-ground and phase-to-phase characteristic of distance protection can be set independently. ° The unique power swing blocking releasing logic and can properly supervise distance protection during power swing, which ensures distance protection to operate correctly for internal faults during power swing, and prevents distance protection from mal-operation during power swing. Unique phase selector has the same protection zone as operation element. The phase selection is automatically resulted according to the reliability of phase selector, so that to avoid probable mistaken multi-phase selection by adopting overreaching phase selector. The overcurrent protection is combined with harmonic blocking and cold load starting logic, which can prevent from mal-operation affected by impulse current while the transformer is initiated on no-load. Selectable IEC, ANSI inverse-time characteristic curves, also the curve can be defined by users and the inverse-time dropoff curve selection is supported. Support single-ended impedance-based fault location, mutual compensation for parallel lines arrangement is also available. Support ping-pang synchronization mode. Both dedicated fiber channel and multiplexing fiber channel are supported, and single mode and multi-mode channel combination operation mode is enable. Communication rate supports 64kbit/s and 2Mbit/s, and communication protocol supports C37.94 and G.703.

Functions Protection and Control • DPFC current differential protection (87L) Phase-segregated percentage differential characteristic, reflects superimposed quantities which can recognize the sensitive protection for high impedance faults. Dynamic capacitive current compensation, adaptive restraint threshold and CT saturation detection are integrated to achieve a combination of both dependability and security. • Steady-state current differential protection (87L) Phase-segregated percentage differential characteristic, dynamic capacitive current compensation, adaptive restraint threshold and...

breaker auto-reclosing with synchronism and voltage check logic. • Remote/local control The control of circuit breaker, disconnector and earth switch can be implemented via communication, LCD menu and binary inputs. User programmable interlocking logics are available by PCS-Studio. • Synchrocheck (25) Synchrocheck can be used for auto-reclosing and manual closing for single-breaker and dual-breaker. The synchronism check function compensates for breaker close time, frequency, magnitude, and angle differences between the two voltage sources used for synchronism. • Voltage and current drift...