RCS-951A HV Transmission line protection equipment

Application

RCS-951A is a microprocessor based protection equipment used for main and back-up protection of transmission line in small ground current system.

Composition

The equipment comprises complete three zones phase-to-phase distance relay, four zones directional overcurrent relay and low frequency protection. It is equipped with tripping and closing operation circuits, potential transformer switching circuit as well as functions of 3 pole one shot auto-recloser and overload alarm. Its sampling rate could trace variation of the frequency.

General

• The equipment uses an integral front panel and closed cabinet with high immunity. The wiring on the panel is simplified by using connectors for external connections. Commissioning and configuration in the site could be done convemiently by dedicated tuning and testing instrument developed by our company.
• DSP and monolithic computer modular design are used for the equipment. The DSP performs protection algorithm and logic discrimination functions. The monolithic computer performs general starter, communication, event record, oscillogram record and other auxiliary functions. Data acquisition of these two parts are independent to each other. Positive pole of power supply of output relays could be closed only when the general starter starts. So unwanted operation of the protection due to any single component failure could be avoided.
• On the premise of higher sampling rate 24 points per cycle, all protection calculation and logic discrimination could be done within one sampling period due to parallel calculation for all protection relays. Principal relays adopt complete cycle Fourier algorithm with high reliability and security. Event record and protection logic calculation are completed simultaneously and no mistake could be caused in the record due to operation of various CPUs during complicated fault conditions.
• Man-machine interface consisted of LCD and a 9 button keypad on the panel is ver friendly to the user. A serial port is equipped for communication with PC. Commissioning and configuration could be done more conveniently on PC.

Features

• High capacity memory and high speed DSP is adopted. Design of hardware is meticulous, succinct, reliable and with high redundancy.
• Operating speed is very high: 10 ms for close-by fault, 15 ms for middle part fault and 25 ms for remote fault.
• The distance relay could detect remote tripping during unsymmetrical fault.. It could operate in cascade and trip fault at end of the line hastily.
• In double circuit line case, distance relay could operate in cascade by transverse comparison of operation of distance elements on both lines and trip fault at end of the line hastily.
• As setting of zone I of distance relay could be as small as 0.01 (In = 5 A), the equipment suits short lines.
• Advanced and reliable blocking function for power swing ensures blocking during power swing and swing plus external fault and the blocking could be disabled quickly during internal fault.
• Capacity of the recorder is high enough. Information recorded is complete, safe and reliable. Format of the record is compatible with international COMTRADE format.
• The equipment is equipped with ether net port and RS-485 serial ports and supports protocol IEC 60870-5-103.

Technical data

Ratings DC control voltage 220 V, 110 V Tolerance +15% - -20% AC voltage 100 V /3 AC current 5 A, 1 A Line voltage for recloser 100 V, 57.7 V Frequency 50 Hz	Overload alarm Setting rqnge 0.1 In - 20 In Tolerance < 5% Range of delay of output 0 s - 10 s
Power consumption AC current circuit at rated current < 0.5 VA / ( In = 5 A) < 0.25 VA / ( In = 1 A) AC voltage circuit at rated voltage < 0.5 VA / DC control circuit quiescent < 20 W energized < 35 W	Fault location Accuracy 2.5%
	Auto-recloser Phase difference of synchronism checking 0-90,tolerance<3 Live line detector Pick-up value >40 V, tolerance < -2 V Dead line detector Pick-up value <30 V, tolerance <+1.5 V
Operation time of complete equipment Zone I of distance protection < 30 ms	Recorder Number of events to be recorded 128 Number of oscillograms to be record 24
Starter Pick-up range of I starter 0.1 In - 0.5 In Pick-up range of zero sequence current starter 0.1 n - 0.5 In	Number of groups of setting value 30
Protection relays Overcurrent relay Pick-up range 0.1 In - 20 In Tolerance < 5% Range of time delay of delayed zones 0 s - 10 s Distance relay Pick- up range for impedance 0.01- 25 (In = 5 A) 0.05- 125 (In = 1 A) Tolerance < 5% Accurate operating voltage < 0.25 V Minimum accurate operating current 0.1 In Maximum accurate operating current 30 In Range of time delay of delayed zones 0 s - 10 s Low frequency protection	Communication Serial port 2, ether net or RS-485 Port for time synchronism with GPS 1 Port for printer 1, local or network printer Protocol IEC 60870-5-103
	Ambient temperature Normal operation -5- 40 Extreme range - 10- 55
	EMC test 1 MHz bursts disturbance IEC 60255-22-1, classIII Electrostatic discharge IEC 60255-22-2, classIII Fast transient disturbance IEC 60255-22-4, classIV Radiated electromagnetic field IEC 60255-22-3, classIII 10 V/m, ( 25-1000 ) MHz
	Insulation test Insulation IEC 60255-5 2 kV, AC, 1 min Impulse IEC 60255-5