Category: Industry Trends

Current protection

Instantaneous phase overcurrent protection (PIOC, 50)

The instantaneous three phase overcurrent function has a low transient overreach and short tripping

time to allow use as a high set short-circuit protection function, with the reach limited to less than

typical eighty percent of the power line at minimum source impedance.

Four step phase overcurrent protection (POCM, 51_67)

The four step phase overcurrent function has an inverse or definite time delay independent for each

step separately.

The single input overcurrent function has a low transient overreach and short tripping times to

allow use as a high set short circuit protection function, with the reach limited to less than typical

eighty percent of the power line at minimum source impedance. The function can be configured

to measure the residual current from the three phase current inputs or the current from a separate

current input.

Four step residual overcurrent protection (PEFM, 51N/67N)

The four step single input overcurrent function has an inverse or definite time delay independent for

each step separately.

All IEC and ANSI time delayed characteristics are available together with an optional user

defined characteristic.

Functionality

Differential protection

High impedance differential protection(PDIF, 87)

The high impedance differential protection can be used when the involved CT cores have same turn

ratio and similar magnetizing characteristic. It utilizes an external summation of the phases and neu

tral current and a series resistor and a voltage dependent resistor externally to the relay.

The function can be set to be directional or non-directional independently for each of the steps.

Instantaneous residual overcurrent protection (PIOC, 50N)

The single input overcurrent function has a low transient overreach and short tripping times to

allow use as a high set short circuit protection function, with the reach limited to less than typical

eighty percent of the power line at minimum source impedance. The function can be configured

to measure the residual current from the three phase current inputs or the current from a separate

current input.

Four step residual overcurrent protection (PEFM, 51N/67N)

The four step single input overcurrent function has an inverse or definite time delay independent for

each step separately.

All IEC and ANSI time delayed characteristics are available together with an optional user

defined characteristic.

A number of protection functions are available for flexibility in use for different station types and

busbar arrangements. The auto-reclose for single-, two-, and/or three-phase reclose includes priority

circuits for multi-breaker arrangements. It co-oper ates with the synchrocheck function with quick or

delayed reclosing. Several breaker failure functions are included to provide a breaker failure

function independent from the protection IEDs,also for a complete one- and a half breaker diameter.

High set instantaneous phase and earth overcur rent, 4 step directional or un-directional delayed

phase and earth overcurrent, thermal overload and two step under and overvoltage functions are

examples of the available functions allowing user to fulfill any application requirement.

Disturbance recording and fault locator are avail able to allow independent post-fault analysis after

primary disturbances with a single failure in the protection system.

6 x 32 dual directional channels for intertrip and binary signals transfer is available in the commu

nication between selected IEDs inside the station or in a near-by station.

The advanced logic capability, where the user logic is prepared with a graphical tool, allows spe

cial applications such as automatic opening of disconnectors in multi-breaker arrangements, closing

of breaker rings, load transfer logics etc. The graphical configuration tool ensures simple and

fast testing and commissioning.

Application

The REC 670 IED is used for the control, protection and monitoring of different types of bays in

power networks. The IED is especially suitable for applications in distributed control systems with

high demands on reliability. The IED can be used up to the highest voltage levels. It is suitable for

the control of all apparatuses in any type of switchgear arrangements.

The control is performed from remote(SCADA/Station) through the communication bus

or locally from a graphical HMI on the front of the IED showing the single line diagram.

Different control configurations can be used, e.g. one control IED can be used per bay or one IED can be

common for several bays. Interlocking modules are available for all common types of switchgear

arrangements. The control is based on the select-execute principle to give highest possible

reliability. A synchrocheck function is available to interlock breaker closing.

The advanced logic capability, where the user logic is prepared with a graphical tool, allows spe

cial applications such as automatic opening of disconnectors in multi-breaker arrangements, closing

of breaker rings, load transfer logics etc. The graphical configuration tool ensures simple and

fast testing and commissioning.

Serial data communication is via optical connections to ensure immunity against disturbances.

The wide application flexibility makes this product an excellent choice for both new installations and

the refurbishment of existing installations.

Functions 

• Metering

– Pulse counter logic (GGIO)

• Station communication

– IEC61850-8-1 communication

– LON communication protocol

– SPA communication protocol

– IEC 60870-5-103 communication protocol

– Horizontal communication via GOOSE for interlocking

– Single command, 16 signals

– Multiple Command, 80 blocks with 16 signals each

– Ethernet configuration of links

• Remote communication

– Binary signal transfer

• Basic IED functions

– Self supervision with internal event list

– Time synchronization (TIME)

– Parameter setting groups

– Test mode functionality (TEST)

– Change lock function

– IED identifiers

– Rated system frequency

• Hardware

– Power supply module (PSM)

– Binary input module (BIM)

– Binary output module (BOM)

– Binary in/out module (IOM)

– mA input module (MIM)

– Transformer input module, standard compression connection terminals (TRM)

– Optical ethernet module (OEM)

– SPA/LON/IEC module (SLM)

– Line data communication module (LDCM)

– GPS time synchronization module (GSM)

• Accessories

– GPS antenna, including mounting kit

– External interface converter from C37.94 to G703

– High impedance resistor unit

– Test switch module RTXP24

– On/off switch

• Frequency protection

– Underfrequency protection (PTUF,81)

– Overfrequency protection (PTOF,81)

– Rate-of-change frequency protection(PFRC,81)

• Multipurpose protection

– General current and voltage protection(GAPC)

• Secondary system supervision

– Current circuit supervision (RDIF)

– Fuse failure supervision (RFUF)

• Control

– Synchrocheck and energizing check(RSYN,25)

– Autorecloser (RREC,79)

– Apparatus control for single bay, max 8 app.(1CB) incl. Interlocking (APC8)

– Apparatus control for single bay, max 15 app.(2CBs) incl. Interlocking (APC15)

– Apparatus control for up to 6 bays, max 30app. (6CBs) incl. Interlocking (APC30)

• Logic

– Tripping logic (PTRC, 94)

– Trip matrix logic

– Configurable logic blocks

– Fixed signal function block

• Monitoring

– Measurements (MMXU)

– Supervision of mA input signals (MVGGIO)

– Event counter (GGIO)

– Event function

– Disturbance report (RBDR)

– Fault locator (RFLO)

Functions 

• Differential protection

– High impedance differential protection (PDIF,87X)

• Current protection

– Instantaneous phase overcurrent protection(PIOC,50)

– Four step phase overcurrent protection(POCM,51/67)

– Instantaneous residual overcurrent protection(PIOC,50N)

– Four step residual overcurrent protection(PEFM,51N/67N)

– Thermal overload protection, one time constant (PTTR,26)

– Thermal overload protection, two time constants (PTTR,49)

– Breaker failure protection (RBRF,50BF)

– Stub protection (PTOC, 50STB)

– Pole discordance protection (RPLD,52PD)

• Voltage protection

– Two step undervoltage protection (PUVM,27)

– Two step overvoltage protection (POVM,59)

– Two step residual overvoltage protection(POVM,59N)

Features

• Selectable additional software functions such as breaker failure protection for each breaker,

voltage protection, thermal protection, control and monitoring

• Built-in data communication modules for station bus IEC 61850-8-1

• Data communication modules for station bus IEC 60870-5-103. LON and SPA

• Remote end communication function with capability for 192 binary signals

• Integrated disturbance and event recorder for up to 40 analog and 96 binary signals

• Time synchronization over IEC 61850-8-1. LON,SPA, binary input or with optional GPS module

• Analog measurements accuracy up to below 0.5% for power and 0.25% for current and volt

age and with site calibration to optimize total accuracy

• Versatile local human-machine interface

• Extensive self-supervision with internal event recorder

• Six independent groups of complete setting parameters with password protection

• Powerful software PC tool for setting, disturbance evaluation and configuration

• Remote end data communication modules for C37.94 and G.703

Features

• A control, protection, and monitoring IED with extensive functional library and configuration

possibilities and expandable hardware design to meet specific user requirements

• For all types of busbar arrangements

• Control functionality with upto 30 controllable apparatuses

• Type tested interlocking for single, double and one- and a half breaker arrangements

• High impedance differential protection for tee-feeders

• Synchrocheck and dead-line check function for single- or multi-breaker arrangements:

– Selectable energizing direction

– Two functions with built-in voltage selection

– For automatic or manual synchrocheck and with different settings

• Auto-reclosing function for single- two-, and/or three-phase reclosing:

– Two functions with priority circuits for multi-breaker arangements

– Co-operation with synchrocheck function

– Can be switched On-Off from remote through communication

or with local switches through binary inputs

• Selectable additional software functions such as breaker failure protection for each breaker,

voltage protection, thermal protection, control and monitoring

Installations with rectangular load cells below the lower back up roll or above the upper back up roll:

Accessible parts: Mounting surfaces in the mill stand, the sledges if present, the rockers,

the pressure plates closest to the load cells and

intermediate mating plates if present.

Installations with circular load cells under the screw-down or hydraulic cylinder:

Accessible parts: Mounting surfaces above the upper back up roll

bearing chuck, plain or tapered thrust roller bearings, pressure plates

closest to the load cells and other intermediate mating plates if present.

Installations with annular load cells above the screw-down inside the mill stand:

Accessible parts: Mounting surfaces of the screw-down nut, plain or

tapered thrust roller bearings, pressure plates closest to the load cells.

The parts and mounting surfaces mentioned above need to be accessible

before the start of the work or otherwise the investigation of

them need to be planned for in advance so that it can be performed

later during the site visit.