MiCOM P441, P442 & P444 numerical full theme distance relays give versatile, reliable,protection, management and observation of transmission lines. The MiCOM distance relay may be applied for a good vary of overhead lines and underground cables in high voltage systems. The wide selection of communication choices facilitate in simply connecting the relay to any style of Digital system or SCADA.The optional redundant ethernet board (P442/P444 only) reduces the price MiCOM of possession since the relay is natively embedded with the switch board. This reduces the number of stand alone switches required, reducing the wiring, power offer and maintenance prices. what is more, increasing the availability rate decreases the chance of electrical outages.
MiCOM P441, P442 and P444 Numerical Full theme Distance Relays give comprehensive distance protection for various applications like:lines, cables, tapped lines, lines with multiple zero sequence sources, non-homogeneous lines,series compensated lines and parallel lines.
The severally settable resistive reach for every zone permits simple application to short lines and cable protection. using well-proven, patented techniques to directionalise, and creating full use of digital memory.
The relays may be applied in things which will cause classic distance implementations to maloperate (cross-country faults, close-up faults, etc.).The MiCOM P441, P442 and P444 are in-built with a library of channel aided theme logic, supplementary and back-up protection. It provides complete protection (4 various setting groups) to solidly earthed systems from
distribution to transmission voltage levels.
Three section tripping with faulted section indication is provided for all protection functions. additionally models P442 and P444 permit single-phase tripping for the space protection and also the channel aided DEF protection (67N).
The P441, P442 and P444 distance relays equipped with 150MHz central processor and microprocessor board are increased as described within the Protection Functions summary table given below.
The operation of the gap relay is predicated on the combined use of 2 fault detection algorithms:
• Calculation of the superimposed current and voltage values that are characteristic of the fault (“Delta” algorithms).
• mensuration of electrical resistance values (“Conventional” algorithms).This twin formula offers reliable MiCOM detection of all kinds of faults within the network. The electrical resistance calculations ar performed each sample for all six loops an, BN, CN, AB, BC and CA, creating this a real full theme
numerical distance relay. supported transient elements, the delta formula could be a patented technique with nearly twenty years of expertise in varied relays. The delta formula uses the superimposed MiCOM signals, that seem throughout faults, for fault detection, section choice and direction determination. The directional component uses the sign of the energy calculated from ΔV and ΔI to make a decision the direction of the fault
• for a forward fault ΔV and ΔI are of opposite polarity (sign of energy: negative) and
• for a reverse fault ΔV and ΔI are of identical polarity (sign of energy: positive).
A power swing is detected once the impedance locus takes quite 5ms to cross the ΔR and ΔX band. Any of the zones (Z1/Z1X, Z2, Z3, Zp, Zq or Z4) is by selection blocked. Four separate parts is set to override the ability swing obstruction just in case of major faults. (Delta technique is employed in part selection) The relay will differentiate a stable power swing
from out of step conditions, by observance the sign of the resistance.
SOTF (SWITCH ON TO EARTH FAULT)
The Switch-On-To-Fault and Trip On Reclose protection offers quick fault clearance following manual or auto-reclosing of circuits breakers respectively.
CHANNEL-AIDED SCHEME LOGIC
The relay is supplied with a comprehensive choice of IEC and ANSI/IEEE compatible channel-aided schemes.
• Permissive beneath reach Protection, accelerating Zone a pair of (PUP Z2),
• Permissive beneath reach Protection, Tripping via Forward begin (PUP forward),
• Permissive Overreach Protection with bold Zone one (POP Z1),
• Permissive theme Unblocking logic, (Loss of Guard, Loss of Carrier)
• blocking Overreach Protection with, bold zone a pair of (BOP Z2),
• blocking Overreach Protection with, bold zone one (BOP Z1),
• Weak in feed and Echo logic Current reversal guard logic is offered to prevent tripping of a healthy line in double circuit lines.
BACK UP/TIME DELAYED PROTECTION
Phase overcurrent: Four independent stages of section overcurrent protection with 2 stages settable as directional and IDMT are available.Nine IEC/IEEE IDMT curves are provided to
• Earth fault: Four stand-by earth fault parts,all are often set directional and either DT or IDMT
with an possibility of timer hold on reset. each parts are often enabled at an equivalent time.
• Voltage: 2 freelance stages of over andunder voltage protection are provided. One of
them are often confgured to work with inverse characteristics.
• The broken conductor protection provided detects unbalanced conditions caused by
broken conductors, maloperation of single section of switchgear or by different single phasing
CHANNEL-AIDED DIRECTIONAL EARTH FAULT
Channel aided directional earth fault protection operates in co-ordination with one or 2 remote finish relays. The power-assisted DEF protection is ready to trip single or three-pole exploitation permissive or blocking theme logic. The transmission channels is also constant as those utilized by the gap protection or is also independent. The directivity of the planet fault components is provided by either zero sequence or negative sequence polarization.
Voltage electrical device direction is provided to discover loss of 1, 2 or 3 phases of the
VT signal, providing indication and inhibition of voltage dependent protection components. An opto-input may additionally be confgured to initiate the voltage electrical device direction alarm and
blocking once used with MCBs or different external sorts of voltage electrical device direction.
A separate capacitive voltage electrical device direction part is additionally provided to discover a voltage error because of a capacitance short-circuited during a CVT. The relay detects a permanent little zero sequence voltage and provides AN alarm (adjustable timer).
CIRCUIT BREAKER FAILURE PROTECTION
Circuit breaker failure protection will be used for back tripping upstream circuit breakers, and/or for retripping via a second breaker trip coil once a local breaker failure is detected. The circuit breaker failure logic may be initiated outwardly from alternative protection devices if required.
AUTORECLOSURE WITH CHECK SYCHRONIZING
The P441 provides 3 pole multi-shot (upto four shots) autoreclose with nonmandatory check synchronising. The P442 and P444 offer one and 3 pole multishot (up to four shots) autoreclose with nonmandatory synchronicity check. For each models, the user could choose one, two, 3 or four shot autoreclose cycle, with severally settable dead times and reclaim time. The check synchronisation operate offers independent settings for manual closing and
A fault location algorithmic program, immune to fault resistance and load current, provides distance to
fault in miles, kilometres, ohms or share of line. A mutual compensation feature is provided to eliminate the result of zero sequence mutual coupling from parallel lines.
PROGRAMMABLE SCHEME LOGIC
Programmable theme logic (PSL) permits the user to customise the protection and management functions. it’s additionally wont to programme the practicality of the optically isolated inputs, relay outputs, diode indications, InterMiCOM (control input) and virtual input/ouput using GOOSE. The programmable theme logic contains of gate logic and general purpose timers. The gate logic includes OR, AND and majority gate functions, with the flexibility to invert the inputs and outputs, and provide feedback. The programmable theme logic is confgured mistreatment the graphical MiCOM S1 Studio computer primarily based support code.
All models include:
• A back-lit liquid crystal display (3 lines)
• 12 LEDs (8 programmable)
• An optional IRIG-B port (not P441)
• An RS232 port & an RS485 port
• An optional second RS232 / RS485 / K-Bus port (not P441)
• A download/monitor port
• A battery (supervised)
• N/O and N/C watchdog contacts
• Supervised +48V feld voltage
• 1A/5A dual rated CTs
• IEC 61850-9.2 LE fbre optic input for non-conventional instrument transformers, or merging units
•optional Redundant ethernet ports (IEC 61850-8-1): Px4x devices are often increased with an nonobligatory redundant ethernet board. The redundancy is managed by the market’s quickest recovery time protocols: Self Healing Protocol and twin orienting Protocol permitting bumpless redundancy. what is more, the RSTP (Rapid Spanning Tree) protocol is additionally obtainable. The redundant local area network board supports either modulated or demodulated IRIG-B and therefore the SNTP protocol for time synchronization. The redundant ethernet board additionally encompasses a watchdog relay contact to line alarms just in case of a failure. The opto-inputs, relay outputs and eight of the LEDs are preconfgured as a default, however are often modified by the user. The universal voltage vary opto inputs (from twenty four to 250V dc) are independent and should be powered (if necessary) from the 48V feld voltage obtainable from the relay. The relay outputs is also confgured as latching or self-reset. All CT connections have in-built shorting