Protection
Metering
Man Machine Interface (front panel)
Control and monitoring
Communication
Software /
Sepam series 20 specification form
Since the Protection and Control unit is installed in the switchgear, it must meet the severest environmental withstand requirements, in particular:IEC standards:
n 60255-5 impulse withstand: 5 kV
n 60255-22-1 1Mhz wave: Class III
n 60255-22-4 fast transients: Class IV
n 61000-4-3 electromagnetic radiation: class III
n 60529 degree of protection: IP 52 on front panel
n 60255-21-1,2,3 vibration, shocks, earthquakes: class II
The operating temperature shall be between -25°C and + 70° C.
One unit shall be designed to accommodate all types of control power supply voltages: 24, 48, 127 & 220 Vdc and 110 & 230 Vac.
The design and manufacturing process shall be ISO 9001
certified.
The Protection and Control Unit shall have UL certification.
It should be possible to withdraw the unit without prior current circuit short-circuiting
The control output relays shall be capable of withstanding steady state current of 8 A.
Operating dependability
The Protection and Control unit shall include:
n an internal function self-monitoring mechanism, which
activates one fail-safe watchdog changeover contacts
n an automatic device for switching to the fail-safe position, disabling output controls when a major internal failure is
detected
n indication of self test status of the device by LED and text.
Installation
The Protection and Control unit should be compact and easy to install
n reduced depth (<100 mm)
n remote optional modules shall be prewired
The Protection and Control Unit shall contain all the necessary protections for the specific application:
n Substation/Feeder protections:
· 50/51 Phase overcurrent
· 50N/51N Earth fault (or neutral)
· 46 Unbalance / negative sequence
· 79 Recloser (4 cycles)
n Transformer protection
· 50/51 Phase overcurrent
· 50N/51N Earth fault (or neutral)
· 46 Unbalance / negative sequence
· 49 RMS thermal overload
· Thermostat / Buchholz
· Temperature monitoring
n Motor protection
· 50/51 Phase overcurrent
· 50N/51N Earth fault (or neutral)
· 46 Unbalance / negative sequence
· 49 RMS Thermal overload
· 37 Phase undercurrent
· 48/51LR Excessive starting time, locked rotor
· 66 Starts per hour
· Temperature monitoring
n Busbar protection
· 27D/47 Positive sequence undervoltage
· 27R Remanent undervoltage
· 27 Phase-to-phase undervoltage
· 27S Phase-to-neutral undervoltage
· 59 Phase-to-phase overvoltage
· 59N Neutral voltage displacement
· 81H Overfrequency
· 81L Underfrequency
· 81R Rate of change of frequency
Each protection device shall have wide setting ranges, in
particular for current protections, providing a choice of curve
types between definite time curve (DT), with time delay settings from instantaneous (50 ms) to 300 s, and IDMT curves (SIT, VIT, LTI, EIT, UIT, RI, IEC SIT / A, IEC VIT or LTI / B, IEC EIT / C, IEEE moderately inverse, IEEE very inverse, IEEE extremely inverse, IAC inverse, IAC very inverse, IAC extremely inverse) adjustable either by time delay or TMS factor.
Phase overcurrent and earth fault protection shall have an adjustable timer hold to allow restriking faults detection.
Earth fault protection shall integrate a harmonic 2 restraint, which can be inhibited or activated.
Alternative overcurrent setting groups will be selectable by logical conditions to adapt fast protection plan change as well as remote setting facilities for thresholds and time delay adjustments.
The unit shall allow for the use of upstream and downstream logic discrimination in order to discriminate correctly when used in a cascade scheme.
Overload protection will be based on RMS current value
(up to a minimum 17th harmonic) and will take into account the ambient temperature.
Alternative overload setting groups will be selectable by logical conditions to adapt operating mode change.
Adjustment of the overload tripping curves will be possible to exactly fit the motor characteristics.
Setting shall be performed by the direct input of actual current
values.
Protection tripping shall be indicated on the front of the device
by a LED and text indicating the cause of the fault.
Each Protection and Control unit shall include the
measurements needed for operation and commissioning, i.e. at
least the following - for feeder, transformer and motor applications:
n RMS 3-phase current measurement
n residual current measurement
n average and maximum phase current demand
n measurement of fault current broken in each phase
n additional measurements such as unbalance ratio, thermal capacity used, ...
The unit shall provide one of the measurement on an analog output
The Protection and Control unit shall include a display unit that indicates:
n measurement values
n operating messages (choice of language English or local)
n device maintenance messages
The display unit shall have as a minimum 2 lines for clear annunciation of alarm conditions.
8 Signals LEDs will be available for alarms and status, including: breaker position (open/closed), relay self test, phase fault and earth fault alarms. It shall be possible to customize the assignment of the signal LEDs.
The display indication shall be in 2 languages
n English
n Local
The Protection and Control unit shall include a keypad to allow to perform the following operations:
n display of metering and operating data, alarm messages
n clearing of alarms and resetting, acknowledgement
n access to protection settings
n access to the unit parameter settings
Access to setting mode will be protected by 2 different customized passwords of at least 4 characters: 1 to protect access to the protection settings, the other to protect access to the unit parameter settings.
It shall be possible to remote the MMI to allow installation of the Protection and Control unit in a different place than the MMI for the most advantageous location for operation & monitoring.
The Protection and Control unit shall include the logic inputs
and outputs resources required for control of the breaking device (circuit-breaker or contactor) and for interfacing with the
monitoring or logic process.
The unit shall have at least 4 relay outputs, with extension capability up to 10 logic inputs and 8 relay outputs
Extension of the number of logic inputs and outputs will be possible to :
n CB open and close control, whatever the type of shunt trip or undervoltage release coil control
n ANSI 69 / Inhibit closing
n Remote tripping
n As an option, monitoring of the circuit breaker for maintenance statistics purpose: operating time, charging time, trip circuit supervision (covering power supply, wiring and coil) cumulative total of tripping currents for 5 current ranges, operation counter, pressure (for SF6 circuit breakers)
n As an option, monitoring the temperature (motors, transformers)
n storage of information (even during control power supply
outages).
1 analog output and 8 temperature sensor inputs will be available as an extension to the Protection and Control unit. (transformer and motor applications)
Disturbance recording:
n Triggered on event (automatic or manual)
n Each record will allow to store data for at least 80 periods, 12 values per period, with a number of periods before the event according to the setup
n The content of the record will be, as a minimum, the date, channel characteristics, 4 current channels (I1, I2, I3, I0) and the digital inputs
n The number of records will be as a minimum 2 events
n The event format shall be COMTRADE 97
The unit will provide time-tagging of minimum 64 events within an accuracy of 1ms.
The Protection and Control unit will be supplied with a
Communication interface option of the RS 485 type, up to
38 400 baud speed, Modbus Protocol.
The response time for a control order will be less than 15 ms (time from order sent to the unit up to order acknowledgement)
The Protection and Control unit will communicate the metering data, enable the remote readings of the protection settings, the remote setting of protection and the transfer of the disturbance recorded data.
Remote control orders shall be carried out in 2 modes :
n Direct mode
n "SBO" (select before operate) mode
A RS232 connection port shall be available in the front of the relay, allowing to communicate between the relay and a PC with the appropriate software.
Appropriate software (using standard Windows 95 or NT operating system) will allow to collect:
n all metering and operating data, alarm messages
n breaker diagnostics data (cumulative tripping current, operating counter…)
n protection and parameter settings, logic status of inputs, outputs and signal LEDs. (download to/from the relay)
n disturbance recording: single or multi curve display, 2 pointers for differential measurement, zooming, printing.
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Sepam series 20 Specification form Medium Voltage Protection Relay