MRRP. Digital Reverse Power Relay. P&B Engineering Belle Vue Works Boundary Street Manchester M12 5NG Tel: Fax:

MRRP Digital Reverse Power Relay P&B Engineering Belle Vue Works Boundary Street Manchester M12 5NG Tel: 0161 230 6363 Fax: 0161 230 6464

Contents CONTENTS... I 1. INTRODUCTION... 1 2. APPLICATIONS... 2 3. FEATURES AND CHARACTERISTICS... 2 4. DESIGN... 3 4.1. Application Diagrams... 3 4.1.1 Analogue input circuits... 4 4.1.2 Output relays... 4 4.1.3 Remote data communication... 4 4.2 Front panel... 4 4.2.1 Display... 4 4.2.2 LED indicators... 5 4.2.3 Push buttons... 5 4.3 Code jumpers... 6 4.3.1 Password programming... 6 4.3.2 Alarm and Trip relay function... 6 5. WORKING PRINCIPLES... 7 5.1 Analogue Circuits... 7 5.2 Digital Circuits... 7 5.3 Power supply... 8 5.4 Measuring Principles... 8 5.5 Requirements for the main Current Transformers... 9 6. OPERATION AND SETTING... 9 6.1 Layout of the control elements... 9 6.2 Relay setting principles... 9 6.2.1 Password protected parameter adjustment... 10 6.2 Setting Procedure... 10 6.2.1 Settings for Overpower (P>), Underpower (P<) and Reverse Power (Pr)... 10 6.2.2 Tripping Times for Overpower (P>), Underpower (P<) and Reverse Power... 11 6.2.3 Y/ - Change Over of the Input Transformers... 11 6.4 Indication of measured values and fault data... 12 6.4.1 Indication of measured values... 12 6.4.2 Indication of fault data... 12 6.5 Test Trip... 13 6.6 Reset... 13 6.6.1 Hand reset... 13 6.6.2 Auto-reset at Power Up... 13 6.7 Setting value calculation... 13 6.8 Setting Values... 13 6.8.1 Nominal Power... 13 6.8.2 Conversion to Setting... 13 6.8.3 Star-Delta Connection... 14 6.8.4 Setting Calculation Example... 14 7. RELAY CASE... 15 7.1 Individual case... 15 7.2 Rack mounting... 15 7.3 Terminal connections... 15 8. TEST AND MAINTENANCE... 15

9. TECHNICAL DATA... 16 9.1 Measuring Input Circuits... 16 9.2 Common Data... 16 9.3 Setting Ranges and Steps... 17 9.4 Output contact ratings... 17 9.5 System data... 17 9.5 Housing... 18 9.6 Connection Details... 19 10. ORDER FORM... 20 08/10/98 ii Issue J

1. Introduction The application of powerful microprocessors opens a new chapter for power system protective relaying. The digital processing of measured values and the ability to perform complex arithmetic and logic operations, give digital protection relays significant performance and flexibility improvements over their traditional analogue counterparts. Additional advantages - very small power consumption, adaptability, self-supervision, fault diagnosis through fault data recording, smaller physical construction and selectable relay characteristics - all combine to allow the implementation of accurate and highly reliable protection schemes at a significantly reduced financial burden. The development of microprocessor based protective relays and their introduction into the market has been stimulated by the recent trend to replace analogue with digital equipment. This modern trend has prompted the development of a new P&B protective relay family - the MR relay series. This comprehensive family of protection relays can satisfy the demands of even the most complex protection schemes: MRI - Overcurrent Relay (Independent time/i.d.m.t + earth + directional facilities) MRI-V - Voltage Dependent Overcurrent Relay MREF - Restricted Earth Fault Relay MRAR - Auto-Reclosing Relay MRMF - Mains Failure Relay MRVT - Voltage Protection MRFT - Frequency Protection MROS - Vector Surge or Rate of Change of Frequency MRNS - Negative Sequence Relay MRRP - Power Relay MRCS - Check Synchronising Relay MRFF - Field Failure Relay MRDG - Differential Relay The superiority of digital protective relaying over traditional analogue devices, as embodied by the MR relay family, is summarised by the following features: Integration of many protective functions in a single compact case High accuracy owing to digital processing Digital relay setting with very wide setting ranges and fine setting steps Comfortable setting procedure through extensive human - relay dialogue Measured values and fault data indication by means of alpha-numeric display Data exchange with DCS/SCADA by means of RS485 Operational reliability through self-supervision A similar but simplified range, with reduced functions and without display, is also available. The MIRI - overcurrent and earth fault relays, and the MIRV - undervoltage, overvoltage and neutral voltage displacement relays. To complement the MR series, a range of Auxiliary, Timing and Tripping devices are also available. 08/10/98 1 Issue J

2. Applications The MRRP relay is used for single and three phase power measurement in low and medium voltage networks. It serves: For supervision of load flow between two systems. If the power generation of one system fails, then non critical users have to be disconnected by the MRRP Relay. Thereby the mains is stabilised and the supply to critical users is maintained. For generators operating in parallel the users can be disconnected if the load remains below the set minimum value or, in peak operating mode, be connected if the set value for the mains power is exceeded. As a reverse power relay, to protect turbines and diesel generators from reverse power if the prime mover fails. For generators operating in parallel with mains supply or another generator, it is imperative to supervise the power direction. If, for example, the prime mover fails, the alternator operates as a motor and drives the generator (diesel or turbine). The MRRP recognises the reverse power direction and switches off the alternator. This way power losses and danger to the prime mover are avoided. 3. Features and characteristics Complete digital processing of the sampled measured values Extremely wide setting ranges with fine setting steps Unauthorised user access control through password protection User defined password Continuous self-supervision of software and hardware Outstanding design flexibility for easy selection of appropriate operational scheme for numerous applications Numerical display of setting values, actual measured values and memorised fault data etc. Serial data communication facilities via RS485 Wide voltage range for DC or AC power supply Withdrawable modules with automatic short circuit of C.T. inputs 08/10/98 2 Issue J

4. Design 4.1. Application Diagrams MRRP-1 L3 L2 L1 Supply 1 2 CASE External Reset Blocking Input 53 54 55 L N L 21 POWER SUPPLY 22 I1 31 TRIP SIGNAL 29 33 32 30 34 38 P> 36 40 37 Alternative Earthing 15 16 V1 MRRP-1 ALARM INDICATION - SELF SUPERVISION RS485 + Gnd P< REVERSE POWER 35 39 43 41 45 44 42 46 49 47 51 50 48 52 Typical Earthing Shown 7 9 10 MRRP-3 L3 L2 L1 Supply 1 2 CASE External Reset Blocking Input 53 54 55 L N L P2 S2 21 POWER SUPPLY P1 S1 22 23 24 25 26 I1 I2 I3 TRIP SIGNAL P> 31 29 33 32 30 34 38 36 40 37 Alternative Earthing 15 16 17 18 19 20 V1 V2 V3 MRRP-3 ALARM INDICATION - SELF SUPERVISION RS485 + Gnd P< REVERSE POWER 35 39 43 41 45 44 42 46 49 47 51 50 48 52 Typical Earthing Shown 7 9 10 08/10/98 3 Issue J

4.1.1 Analogue input circuits The constantly detected measuring values are galvanically decoupled, filtered and finally fed to the analogue/digital converter. The protection unit receives these analogue input signals for the phase currents I1, I2 & I3, and phase voltages V1, V2 & V3 via separate input transformers. 4.1.2 Output relays The MRRP has five output relays, with single or dual pole change-over contacts as detailed in the previous diagrams and summarised below: Tripping relay (2) Self-supervision alarm relay (1) Overpower alarm relay (2) Underpower decrease alarm relay (2) Reverse power relay (1) 4.1.3 Remote data communication As an option, the MRRP may have an RS485 interface for remote data communication with a control centre. The unit provides the following information: Actual measured current, voltage and power values Recorded measured current, voltage and power values Status signals Self supervision alarm signal Relay settings Alarm and trip signalling 4.1.4 Blocking Input When required to inhibit all the functions of the relay, the auxiliary supply is connected to the blocking input terminals, 54-55. 4.2 Front panel The front panel of the MRRP comprises the following operation and indication elements: Alphanumeric display (4 Digits) 5 push buttons for setting and other operations 11 LEDs for measured value indication and setting 4.2.1 Display The measured and set values, and recorded fault data, are shown alphanumerically on the display. The meaning of the displayed values is easily interpreted from the LED indicators on the front panel. 08/10/98 4 Issue J

Table: Adjustment possibilities by means of the front panel. Function Display Shows Push-button Pressed LED Illuminated Normal Operation P&B <SELECT> for 3 s Inquire Password PSW? <ENTER>/<TRIP> Save Parameter SAV? <ENTER> Saved Parameter SAV! <ENTER> Manual Trip TRI? <TRIP> Relay Tripped TRIP <TRIP> L1,L2,L3,, Enter Password XXXX Combination of <SELECT>,< >,< > or <ENTER> Measured Values Currents as related to <SELECT> L1,L2,L3,U,I In, Power as related to Pn & Actual Voltages Fault Data Tripping values <SELECT> L1,L2,L3,P>,P<,Pr Adjustable Values 4.2.2 LED indicators P>,P<,Pr Star/Delta setting "DELT"/"Y". Overpower P>. Tripping time, tp>. Underpower P<. Tripping time, tp<. Reverse Power Pr. Tripping time, tpr. <SELECT> < > < > L1,L2,L3 The LEDs to the left of the display indicate measuring or tripping values. The purpose of the corresponding LED is identified by the adjacent inscription, (e.g. L2 for current in phase 2). The first row of three LEDs to the left of the display are bi-coloured - green indicates measuring and red indicates fault condition. The four LEDs below the display are bi-coloured; green for P>, P<, Pr and D/Y. Red for tp>, tp< and tpr. The MRRP also has an LED to indicate direction (green and red arrows). Green indicates generator power, red indicates reverse power. The LED marked RS indicates active serial data communication. 4.2.3 Push buttons The front panel contains five push buttons used for setting, measuring and other user functions. The individual setting and measuring values can be selected in turn by pressing the <SELECT> / <RESET> push button. This button also resets the relay if pressed for approximately 3 seconds. The <UP> and <DOWN> push buttons are for incrementing and decrementing any selected parameter. Continuous pressing of these push buttons will cause the parameter to change at an increased rate. P> tp> P< tp< Pr tpr 08/10/98 5 Issue J

The <ENTER> push button is used to transfer the indicated value to the internal parameter memory. An unintended or unauthorised change of the selected parameter can be avoided through the password protection facility. The <TRIP> push button is used to test the output relay circuits, both for tripping and signalling. This operation is also password protected. 4.3 Code jumpers Behind the front panel of the MRRP are three code jumpers used to precept the following functions: Password programming Alarm and Trip relay functions The following figure shows the position and designation of the code jumpers Front Board Code Jumper J3 J2 J1 Code Jumper ON Code Jumper OFF 4.3.1 Password programming The MRRP relay is normally delivered with the precept password " ". It can be reprogrammed using the removable code jumper J1. After power on and the pressing of any push button, the MRRP relay enquires for a new password with the text <PSW?> appearing on the display. A new password is then entered by pressing a combination of <SELECT>, <UP>, <DOWN> or <ENTER>, as chosen by the user. After the new password has been given, the relay module is extracted from its case and code jumper J1 removed. 4.3.2 Alarm and Trip relay function The following functions of the MRRP alarm relays may be precept using jumpers J1 & J2: Alarm relay activation upon initiation or after a trip Manual or Automatic reset of the output relays Code jumper J2 - OFF The alarm relays respond directly upon the initiation of the corresponding measuring circuit. Thus, an alarm signal, e.g. for reverse power, will be given before the relay trips. 08/10/98 6 Issue J

Code jumper J2 - ON The alarm relay responds only after the relay has tripped. Thus, the alarm relay and the trip relay respond at the same time. Code jumper J3 - OFF All output relays will be reset automatically after tripping, once the fault has been cleared. Code jumper J3 - ON All output relays remain activated and must be reset manually by pressing the <RESET> push button, after the fault has been cleared. Summarising the coding possibilities Code jumper Function Code jumper Position Operation Mode J1 Password OFF ON Normal position Password programming J2 Alarm Relays OFF ON Alarm relays will be activated on energising. Alarm relays will be activated upon tripping. J3 Reset OFF ON Output relays will be reset automatically. Output relays will be reset manually. 5. Working Principles 5.1 Analogue Circuits The incoming currents from the external current transformers are converted to internal signals in proportion to the currents, via the internal input transducers and shunt resistors. The noise signals caused by inductive and capacitive coupling are suppressed by an analogue RC filter circuit. The analogue signals are fed to the A/D converter of the micro-processor and transformed to digital signals through sample-hold circuits. There is no digital filtering and hence detection of the measured values takes place at a sampling frequency of 900 Hz, namely a sampling rate of 1.11 ms. 5.2 Digital Circuits The essential component of the MRRP relay is a powerful micro-controller. All of the operations, from the analogue digital conversion to the relay trip decision, are carried out by the microcontroller digitally. The relay program, located in EPROM, allows the CPU of the microcontroller to processes current and voltage information and calculate the existing power. The actual measured power is compared with the relay threshold settings. When the power changes beyond the set starting values the unit initiates the corresponding time delay calculation. When the set time delay has elapsed, a trip signal is given. The relay setting values for all parameters are stored in EEPROM, so that the actual relay settings cannot be lost, even in the event of auxiliary supply interruption. The micro-processor is supervised through a built in "Watch-dog" timer. Should a failure occur the watch-dog timer resets the micro-processor and gives an alarm signal via the self supervision output relay. 08/10/98 7 Issue J

5.3 Power supply Two auxiliary power supply versions are available: Vaux = 24V in a range from 16V to 60V AC or in a range from 16V to 80V DC Vaux = 110V in a range from 50V to 270V AC or in a range from 70V to 360V DC 5.4 Measuring Principles Through multiplication of the actual current and voltage values, P(t) = V(t) x I(t), the microprocessor calculates the phase power. 18 values are measured and recorded per voltage cycle from which the mean value of the power during one cycle is calculated: P = 1 x ò P(t) x dt T Consequently, the total three phase current is calculated using; P tot = P1 + P2 + P3 V [t] 0 Time i [t] 0 Time P(t) = V(t) i(t) P [t] 0 Time 1 P = P(t) d(t) T 0 Time 08/10/98 8 Issue J

5.5 Requirements for the main Current Transformers In order to ensure the correct operation of the MRRP range of relays, protection class CT's must be utilised. Instrument CT's are NOT a suitable alternative. CT's should be chosen such that saturation, or loss of accuracy does not occur within the settings and operation ranges of the relays. In the absence of known settings the following may be regarded as an approximate guide. For 1A secondary CT class 5P20 or 10P20 2.5VA (Allowing for up to 1Ω of secondary lead resistance) For 5A secondary CT class 5P20 or 10P20 5VA (Allowing for up to 0.5Ω of secondary lead resistance) with due regard to a suitable CT ratio and fault level capacity. 6. Operation and Setting 6.1 Layout of the control elements All control elements required for the operation and adjustment of the MRRP are located on the front panel. They are divided according to function into the three following groups: Alphanumeric Display: Indication of parameter set values, actual measured values and recorded fault data. LED's: Indication of selected parameters and measured quantities. Push Buttons: Selection of parameter to be adjusted, quantity to be measured and adjustment of parameter values. Where; <SELECT / RESET> <UP> <DOWN> <ENTER> <TRIP> 6.2 Relay setting principles Selection of the parameter to be set and the relay quantities to be measured. Continuous pressing as the reset function. Increment of the setting values for the parameter selected. Decrement of the setting values for the parameter selected. Storage of the setting values for the selected parameter. Testing of the output relay circuits. There are seven relay parameters which may be set for the MRRP: P> Overpower Setting P< Underpower Setting Pr Reverse Power Setting tp> Overpower Tripping Time tp< Underpower Tripping Time tpr Reverse Power Tripping Time D/Y Delta/Star Setting By pressing the <SELECT/RESET> push button, the parameter to be modified is reached. The corresponding LED illuminates on the curve and the present set value of the selected parameter is 08/10/98 9 Issue J

indicated on the display. This set value may then be increased or decreased by pressing the <UP> or <DOWN> buttons respectively. The selected set value is only stored after pressing the <ENTER> push button and inputting the correct password. This means that adjustment of the unit is only possible by authorised users. 6.2.1 Password protected parameter adjustment The adjustment of all relay settings are password protected, however, to enable ease of adjustment, for authorised users, application of the password is usually only required once for multiple parameter adjustment. The following step by step sequence is given to illustrate the implementation of the password protection facility, where a new relay setting is to be applied: After the present setting value has been selected and changed using the <UP>, <DOWN> push buttons, the <ENTER> push button should be pressed. The message <SAV?> appears on the display, to confirm that the new setting value is to be saved. After pressing <ENTER> again, the password will be requested. The message <PSW?> is displayed. After the password has been given correctly, as indicated by the message <SAV!>, the new setting value may be stored by pressing the <ENTER> push button for at least 3 seconds. The new setting parameter then reappears on the display. A password consists of four push button operations. The pressed push buttons and their sequence define the password. If the four push buttons are defined by the following symbols: <SELECT> = S <DOWN> = <UP> = <ENTER> = E Then a password " E S" is achieved by the following sequence: <DOWN> <ENTER> <UP> <SELECT>. After a password is given correctly, parameter setting is permitted for five minutes. Subsequent parameter setting made within the five minute period after the password was inputted, does not require renewed password entry. Furthermore, the valid period for parameter setting is automatically extended for a further 5 minutes after each push button operation. If no push button is pressed within the 5 minute period then the validity of the password will be suspended. To enter further parameters after this period re-application of the password is required. During the 5 minute period when changes may be made, a new set value, acknowledged by <SAV?> then <SAV!>, may be stored by pressing <ENTER> for approximately 3 seconds. 6.2 Setting Procedure 6.2.1 Settings for Overpower (P>), Underpower (P<) and Reverse Power (Pr) After setting the value for Overpower (P>), Underpower (P<) and Reverse Power (Pr); the display indicates a value related to the three phase Nominal Power, Pn. This means: Set Value = Indicated Value x Nominal Power 08/10/98 10 Issue J

The < > and < > push buttons can be used to change the indicated value, once selected the <ENTER> push button is used to store. Both P> and Pr can be blocked by incrementing using the < > button until the display shows "EXIT". P< can be blocked by decrementing until "0" appears and then storing using the <ENTER> key. 6.2.2 Tripping Times for Overpower (P>), Underpower (P<) and Reverse Power After the setting of the tripping times, a value in seconds is shown on the display. The required time delay can by entered by using the < > and < > keys and stored using the <ENTER> key. 6.2.3 Y/ - Change Over of the Input Transformers The voltage sensing circuits of the MRRP may be connected in either star or delta configuration. The relay rated voltage, Vn, refers to the Line-Line voltage in the star connection. The maximum line-to-line voltage must not exceed the thermal withstand, please refer to the Technical Data Section. Input Transformers in Star Configuration L3 L2 L1 N 15 16 17 V1 V2 18 19 20 V3 Typical earthing shown Alternative Earthing Input Transformers in Delta Configuration L3 L2 L1 15 16 17 V1 V2 18 19 20 V3 08/10/98 11 Issue J

6.4 Indication of measured values and fault data 6.4.1 Indication of measured values Any one of the following measured quantities may be indicated on the display during normal service by pressing the <SELECT> button: Total Three-Phase Power (LED's L1, L2, L3 - Green) Power in Phase L1 (LED L1 - Green) Power in Phase L2 (LED L2 - Green) Power in Phase L3 (LED L3 - Green) In Star Connection only: Voltage in Phase L1 (LED's U and L1 - Green) Voltage in Phase L2 (LED's U and L2 - Green) Voltage in Phase L3 (LED's U and L3 - Green) In Delta Connection only: Phase to Phase Voltage V12 (LED's U, L1 and L2 - Green) Phase to Phase Voltage V23 (LED's U, L2 and L3 - Green) Phase to Phase Voltage V31 (LED's U, L3 and L1 - Green) Note: It is only possible to indicate individual phase power when the voltage input transformers are connected in Star configuration. Current in Phase L1 (LED's I and L1 - Green) Current in Phase L2 (LED's I and L2 - Green) Current in Phase L3 (LED's I and L3 - Green) The relevant operating values of the individual measured quantities are indicated on the display and are referred to the rated current and power. 6.4.2 Indication of fault data Visual indication of faults detected by the relay is given on the front panel. The three phase LEDs L1, L2, & L3, as well as the function LEDs P>, P< and Pr are used to indicate/specify fault events. When a fault initiates a relay function, the corresponding function LED illuminates yellow. At the same time, the phase LED(s) flash(es) red to indicate the faulty phase or phases. After the set time delay has elapsed, the relay trips and the LED(s) for the faulty phase(s) become a constant red. The function LED remains illuminated. The fault currents measured at the instant of trip are recorded in registers for fault indication. After the occurrence of a trip, fault data for all three phase currents may be displayed in turn by repeatedly pressing the <SELECT> key. After all phases have been indicated, the LEDs return to red indicating the fault event. By pressing the <SELECT/RESET> button for approximately 3 seconds the relay is reset to its original status. If however, the relay was initiated by the occurrence of a fault, which then fell below a detectable level, a slowly flashing LED corresponding to the detected fault is displayed. This can also be reset using the <SELECT/RESET> button. 08/10/98 12 Issue J

6.5 Test Trip The whole tripping circuit of the protection system may be tested by simulating a fault with the <TRIP> push button. This button is also used to interrogate the relay for its software version number. A single press reveals the first half of the software version number and a second press reveals the second half. A third press will be responded to by <PSW?>. Entering the correct password will be responded to by <TRI?>. Pressing <TRIP> again energises all output relays in turn with a delay time of 1 second. All relays will stay energised until manually reset. 6.6 Reset There are two ways in which to reset the MRRP relay: 6.6.1 Hand reset By pressing the <SELECT/RESET> for approximately 3 seconds the relay is reset. 6.6.2 Auto-reset at Power Up After loss of supply voltage and upon its reconnection the unit resets itself and displays P&B. This resetting of the unit does not effect the set parameters which are stored in an EEPROM. 6.7 Setting value calculation In order to ensure that protection relays form an integral part of any system, a full protection coordination study should normally be undertaken which considers both upstream and downstream equipment. Further details may be obtained by contacting P&B Engineering. 6.8 Setting Values The nominal full load current is not generally the same as the CT ratio. Thus, a significant difference between an apparent setting and the required setting often occurs. 6.8.1 Nominal Power In order to determine the nominal power, Pn, of the relay, it is necessary to take into account the CT & VT ratios and connection arrangement. Pn = 3 In Vn Nv Nc Where; In = Nominal Relay Current rating; Vn = Nominal Relay Voltage rating (measurement); Nv = V.T. Ratio Nc = C.T. Ratio 6.8.2 Conversion to Setting If the required operate power is P op, then the required setting is Pop Set = 100% P n 08/10/98 13 Issue J

6.8.3 Star-Delta Connection If the relay operates on a three wire system, the relay must be set and wired for the Delta connection. If the relay operates on a four wire system, the relay must be set and wired for the Star connection. 6.8.4 Setting Calculation Example A 2.5 MVA 11kV generator of full load current 131A at 0.8 power factor, must be set for trip at an actual reverse power of 5%. The CT ratio is 150/5A, class 10P20. The VT ratio is 11000/110 The relay has a rating of 5A, 100V (In, Vn) Trip Value 5 Pop = = 100 2. 5 0. 8 100kW Nominal Power Pn 5 100 11000 150 = 3 = 110 5 2. 598MW Relay Setting 100 = 100 = 3 85 2598. % In this case, the relay setting of 3.85% corresponds to an actual trip value of 5% of the generator active rated power. 08/10/98 14 Issue J

7. Relay case The MRRP is delivered in an individual case for flush mounting. 7.1 Individual case The MRRP is supplied in a UK manufactured industry standard drawout case suitable for flush mounting. For case dimension and cut-out, refer to Technical Data. 7.2 Rack mounting MRRP relays may be supplied mounted in 19" racks if specified by the user. 7.3 Terminal connections The MRRP plug in module is supplied in a case which has a very compact plug and socket connector. The current terminals are equipped with self closing short circuit contacts. Thus the MRRP module can be unplugged even with current flowing without endangering personnel. 8. Test and maintenance Currents and voltages may be supplied to the input transformers to test the behaviour of the relay. By changing the phase angle between them and measuring the tripping time, the whole system can be accurately tested. All measuring input circuits of the MRRP are of static design and the relay functions are fully digitised. Thus, the MRRP has no particular demand on maintenance. 08/10/98 15 Issue J

9. Technical Data 9.1 Measuring Input Circuits Rated Data Rated Current, In 1 A or 5 A Rated Voltage, Vn 100/110 V, 230/240 V, 400/415 V ** Rated Frequency, Fn 50 Hz to 60 Hz Power Consumption Current Circuits Voltage Circuits @ In = 1 A - 0.2 VA @ In = 5 A - 0.1 VA < 1 VA per phase @ Vn Thermal Withstand Current Circuits Voltage Withstand Half Wave - 250 x In For 1 s - 100 x In For 10 s - 30 x In Continuously - 4 x In Continuously - 1.5 x Vn 9.2 Common Data Drop Off / Pick Up Ratio P> = 50-97% (Adjustable) Pr = 50-97% (Adjustable) P< = <102% Return Time 30 ms Time Lag Error ± 10 ms Minimum Operating Time 30 ms Transient Overreach 5% Sensitivity @ Vn and Cos ϕ = 0.01 x In @ Vn and In to Cos ϕ = 0.0087 89.5 Influences on Measurement Auxiliary Voltage Frequency Delay Times In the range of 0.8 < Vh / Vhn < 1.2 - No influences No Influence No influences ** For setting value calculations, the individual nameplate rating shown on the relay should be used. In the absence of these the underlined figures can be used 08/10/98 16 Issue J

9.3 Setting Ranges and Steps Function Parameter Setting Range Step Tolerances P> / < P> / < tp> / < 0.01-2.0 x Pn 0.5-100 s 0.01, 0.02, 0.05, 0.1 x Pn 0.1, 0.2, 0.5, ± 0.5% Pn ±3% or ±10mS 1.0, 1.0, 5.0 s Pr Pr tpr 0.01-2.0 x Pn 0.5-100 s 0.01, 0.02, 0.05, 0.1 x Pn 0.1, 0.2, 0.5, 1.0, 1.0, 5.0 s ± 0.5% Pn ±3% or ±10mS 9.4 Output contact ratings Number of relays = 5 Contacts Maximum breaking capacity 250V AC / 1500VA / continuous current 6A = contacts for trip relays as detailed in application diagrams 1 change over contact for self supervision relays for DC voltage: ohmic L/R = 4ms L/R = 7ms 300 V DC 0.3 A / 90 W 0.2 A / 63 W 0.18 A / 54 W 250 V DC 0.4 A / 100 W 0.3 A / 70 W 0.15 A / 40 W 110 V DC 0.5 A / 55 W 0.4 A / 40 W 0.2 A / 22 W 60 V DC 0.7 A / 42 W 0.5 A / 30 W 0.3 A / 17 W 24 V DC 6 A / 144 W 4.2 A / 100 W 2.5 A / 60 W Max. rated making current: mechanical life span: electrical life span: Contact material 9.5 System data 64A(IEC65) 3 106 operating cycles 2 105 operating cycles at 220 V AC / 6A Silver Cadmium Oxide (AgCdO) Design standard = IEC 255-4, BS 142 Operating temperature range = -20 C to 70 C Storage temperature range = -40 C to 85 C Relative humidity = 93% @ 40 C for 56 days Test Voltages to EN50081-1, EN50082-2 Isolation Test = 2.5kV / 50Hz / 1 min. Impulse Test = 5kV, 1.2 / 50mS, 0.5J High frequency interference Test = 2.5kV / 1MHz Burst transient Test = 4kV / 2.5KHz, 15mS ESD Test = 8kV RFI Suppression Test = 10V/m, 27-500MHz, 1 Octave/ 3 min. EMI Suppression Test = 10V/m Mechanical Tests: Shock = IEC 41B (CO) 38, Class 1 Vibration = IEC 41B (CO) 35, Class 1 Degree of Protection = Front - IP52 Rear - IP00 Weight = Approx. 2kg. 08/10/98 17 Issue J

9.5 Housing Throughout the MR series range a modular housing system has been employed, utilising the latest high quality UK manufactured industry standard case components. This approach affords maximum flexibility for both the relay scheme designer and the maintenance engineer. The relay modules are fully withdrawable for ease of maintenance and where applicable incorporate automatic short-circuiting CT connections to avoid dangerous open circuit CT overvoltages. A clear plastic front cover is provided for inspection purposes. MRRP units are supplied in standard height (179mm 7in.) cases, complying with IEC 297 size 4U. The rigid case wall is manufactured from a single sheet of hot dipped galvanised steel coated externally with Plastisol PVC and internally with a low gloss alkyd paint finish. This construction technique provides improved thermal transfer characteristics over plastic walled cases and combines exceptional corrosion and flame resilience with good electromagnetic and electrostatic screening properties allowing many relays to be freely situated in close proximity and hazardous environments. When the relay is inserted a leaf spring along the top edge of the module makes contact with a solidly bonded nickel plated steel strip on the interior of the case, providing excellent earth continuity. This strip is brought out at the rear of the case, above the terminal block, where it forms a separate earthing terminal. A rigid front mounting flange is provided allowing the entire range of standard cases to be flush mounted without alteration. These flanges are also used to mount the relay inspection cover which is secured by thumbscrews. Securely bonded channels can be provided on the top and bottom surfaces toward the rear of the case allowing large rigid assemblies to be created by the use of joining strips located in these channels. This uniform but highly flexible housing system integrates excellent mechanical strength with good electrical practice in industry standard sizes. 97 45 10 52 23.5 4 HOLES 4.4mm DIAMETER OPTIONAL 168 159 PANEL CUT OUT FLUSH MOUNTING FIXING DETAILS Min 28 99 PUSH BUTTON PROJECTION 10mm NOTE Minimum gap between vertical spacing is required in order to withdraw relay from the case above. 32 OPTIONAL 212 Clearance 25 min 177 157 103 178 Required to open case NOT SHOWN TO SCALE OPTIONAL SIZE 100 CAS 08/10/98 18 Issue J

9.6 Connection Details The rear terminal block accepts both pre-insulated screw and push-on blade type connectors which may be used singly or in combination. Each terminal has 1 screw type and 2 blade type connectors. Screw: Blade: Combinations: Each connection uses a 4mm (M4) screw outlet and accepts standard L-shaped ring type connectors designed for 4mm screws. Each connection facilitates 2 pre-insulated push-on blades 4.8mm wide 0.8mm thick complying with BS5057. Each terminal will accept either; 2 ring type connectors or 2 push-on blade type connectors or 1 ring type connector & 1 push-on blade type connector Earth Each terminal 1 3 2 4 29 31 30 32 1 screw & 2 spade 5 6 33 34 7 8 35 36 9 10 37 38 11 12 39 40 13 14 41 42 15 16 43 44 17 18 45 46 19 20 47 48 21 22 49 50 23 24 51 52 25 26 53 54 27 28 55 56 Rear terminal block connections. All information subject to change without notice Publication number MRRP-Issue J 08/10/98 19 Issue J

10. Order Form Digital Multifunctional Relay MRRP MRRP No Of Phase Elements 1 3 Reduced Setting Range 3R Rated Current, 1A 1 5A 5 Rated Measurement Voltage, 100 V (110V) 1 230 V (240V) 2 400 V (415V) 4 Power Supply, 24V (16-60Vac, 16-80Vdc) L 110V (50-270Vac, 70-360Vdc) H Data Communications, RS485 R Housing, 19" Rack Flush Mounting A D PBSI Ltd Trading as P&B ENGINEERING Bell Vue Works, Boundary Street, Manchester. M12 5NG. Tel: 0161-230-6363 Fax: 0161-230-6464 08/10/98 20 Issue J