RCS-902A/B UHV Transmission line protection equipment
RCS-902A/B High Speed Protection for UHV Transmission Line
Application
RCS-902A/B is a microprocessor based protection equipment used for main and back-up high speed protection of 220 kV and more UHV transmission line.
Composition
The equipment comprises following parts:
- High-speed main protection including pilot distance relay, pilot zero sequence directional relay and fast zone I of DPFC distance relay;
- Backup protection including three zones phase-to-phase distance relay, three zones ground distance relay and two delayed zones of zero sequence directional overcurrent relay for RCS-902A; three zones phase-to-phase distance relay, three zones ground distance relay and four delayed zones zero sequence directional overcurrent relay for RCS-902B;
- Single pole, 3 pole and 1/3 pole auto-reclosing for circuit breakers of single or double busbar configuration.
Outputs of the protection are phase-segregated.
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 conveniently 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.
- Adaptive floating threshold is adopted for DPFC element. It is insensitive to system unbalance and disturbance. The measuring element could get high security and high speed simultaneously. The starter could get high sensitivity without frequent initiation.
- Operation speed and reliability of DPFC impedance relay is very high. It suits series compen-sated transmission 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.
- Protection performance in weak feed condition is considered perfectly. The equipment could adapt to change of power source of the system automatically.
- The faulty phase could be selected and tripped correctly in high resistance fault case including that developed slowly.
- 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.
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Ratings
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Protection relays (cont'd) Distance protection 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 | ||||
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Power consumption AC current circuit at rated current < 0.5 VA /  ( In = 5 A)< 0.5 VA / ( In = 5 A)AC voltage circuit at rated voltage < 0.5 VA / DC control circuit quiescent < 20 W energized < 35 W |
Fault location Accuracy  2.5% | ||||
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Operation time of complete equipment DPFC distance element Close-by 3 - 10 ms Middle part < 15 ms Zone I of distance protection  20 msPilot protection for whole line < 25 ms |
Auto-recloser Phase difference of synchronism checking 0  -90,tolerance<3Live line detector Pick-up value >40 V, tolerance < -2 V Dead line detector Pick-up value <30 V, tolerance <+1.5 V | ||||
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Starter Pick-up range of  I starte0.1 In - 0.5 In Pick-up range of zero sequence current starter 0.1 n - 0.5 In |
Recorder Number of events to be recorded 128 Number of oscillograms to be record 24 | ||||
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Protection relays DPFC distance relay Operation time < 10 ms ( Uop >2Uz)Pick-up range for impedance 0.1 - 25 (In = 5 A)0.5 - 125 (In = 1 A)Zero sequence directional relay Minimum operating current 0.1 In Minimum operating voltage 0.5 V -1 V Zero sequence overcurrent relay Pick-up range 0.1 In - 20 In Tolerance < 5% Range of time delay of delayed zones 0 s - 10 s |
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3
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EMC test (cont'd) Fast transient disturbance IEC 60255-22-4, classIV Radiated electromagnetic field IEC 60255-22-3, classIII 10 V/m, ( 25-1000 ) MHz |
Insulation test (cont'd) Impulse IEC 60255-5 5 kV, 1.2/50  s, 0.5J |
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Insulation test Insulation IEC 60255-5 2 kV, AC, 1 min |
Chassis Weight 10 kg Dimensions width 482.6 mm (19'') height 177.8 mm (4U) depth 325 mm Flush type mounting, panel cutout 451 mm  179 mm |