RTMU Control & Monitor Relay User Manual
Contents
1. N N a 157 mm RELAY SIDE VIEW RETURN TO CENTRE OFF ON RTMU 2m 157 mm sss N NIJO N IL 177 mm RELAY FRONT VIEW RELAY REAR VIEW CONNECTORS 25 26 amp 27 ON RTUM 1m Figure 13 Relay Type RTMU 1m amp RTMU 2m v2 0 Page 21 of 31 RTMU Control amp Monitor Relay N 5 Commissioning 5 1 Introduction The SuperTAPP voltage control system undergoes full calibration and functional checks during manufacture Some on site checks are necessary to confirm correct operation of the relay and the external connections prior to operation Commissioning of equipment should only be carried out by skilled personnel trained in relay operation and capable of observing all the necessary safety precautions and regulations appropriate to this equipment and also the associated primary plant Ensure that all test equipment and leads have been correctly maintained and are in good condition Full operational checks should be carried out with the transformer s on load using system voltage and currents to ensure that the VT CT relationships both phase angle and magnitude are correct 5 2 Inspection A visual check should be made of all wiring to confirm correct connections Pre testing of the tap change mechanism is assume2. The RTMU control and monitor relays are designed for use with SuperTAPP type RVM relays SuperTAPP n Voltage control relays or as stand alone monitor devices for existing or new voltage control systems When used in conjunction with RVM or SuperTAPP n voltage control relays a comprehensive self contained tap change control system is provided in an extremely cost effective manner such that minimum external wiring is required to complete the installation Two relays are available e RTMU 1m Control and monitor unit with Resistor tap position input BCD Optional RTMU 2m Control and monitor unit with return to centre off Auto Manual position and resistor or BCD tap position input 1 2 Tap Change Monitor Functions 1 2 1 Position Measurement A tap position indicator with mechanical runaway prevention logic monitors each tap change operation and checks that a genuine tap change signal has been initiated 2 2 Voltage Measurement A voltage monitor checks the output voltage of the power transformer and inhibits tap change operations which would cause the voltage to go above or below pre set maximum and minimum voltage levels 2 3 Output Contacts Tap change lockout Relay output contacts are provided such that the tap change motor supply circuit can be disconnected in the event of a runaway situation Voltage monitor Normally closed contacts are provided on each of the high and low monitors which inhibit furthe
3. 95 115 L 90 105 VOLTAGE LIMIT RAISE INHIBIT LOWER INHIBIT Figure 2 RTMU 2m block diagram 1 4 Description of Features 1 4 4 Control Switches The relay includes Auto Manual and Raise Lower control switches these switches are internally connected for inclusion into an overall tap change control scheme see Figure 1 Figure 2 shows the internal arrangement for an Auto Manual selector switch with a return to centre off position This is used in some applications to allow auto manual selection from multiple sources Page 7 of 31 RTMU Control amp Monitor Relay 1 4 2 In Progress Indication An indicator shows that a tap change is in progress and unlike a normal indication which is driven from an auxiliary switch is triggered by e Detection of a raise or Iower control signal A genuine tap position change e Progress auxiliary tap change mechanism switch Given a control raise or lower the IP indication will stay on and an incomplete alarm sent if a tap position change is not detected 1 4 8 Tap Position Indication The tap position indicator is a digital indicator which can be driven by practically any sender unit Runaway prevention logic offers a high degree of protection against inadvertent tap change operations Information given by the display is shown in Figure 3 m m lt ra q E Oooo wo SEES
4. m LL Dp UI Figure 3 Tap position indication display On start up the processor checks internal functions and drives all segments on the display The calculated tap position is then indicated this reading is dependent on the set up switch see commissioning notes and the tap position sender unit output If for any reason the tap position changes other than during a controlled tap changing operation the display will mark the tap position as suspect Ifthe calculated tap position changes to read tap 1 resistor sender unit or tap 0 BCD sender unit the display will read and an alarm will be sent 1 4 4 Runaway Prevention A Runaway can be defined as a condition where the tap changer is operating in a direction which will either cause the voltage to move further away from the desired value and or the circulating current to increase There are two main causes e Wiring fault or mechanism failure on the transformer causing unwanted tap changes e Relay fault causing repeated raise or lower pulses Mechanism Faults If the mechanism is working correctly every tap change operation will be preceded by a new control signal If the mechanism starts to run away a tap change will take place without a further initiating signal The Runaway Prevention Unit monitors every change in tap position via signals from the tap position indicator If after an initial tap change any operations are detecte
5. RTMU Control amp Monitor Relay User Manual RTMU Control amp Monitor Relay Contents 1 Description of Operationen 4 Ted INIOUGENON een 4 1 2 Change Monitor 4 1 2 1 Position Measurementu uuu een iin an 4 1 2 2 Voltage Measurement u seen rennen 4 1 2 3 OUTPUT CONTACTS EC 4 UE o rm 4 1 3 1 Tap Position INGICATION ecco en an 5 1 3 2 Voltage MONITO 2 eed 5 1 4 Description of Features es nee 7 1 4 1 Control Switch s uuu u eae Cuna enden hen nd ua Dade ehe 7 1 4 2 In 8 1 4 3 Position INGICATION uu uuu ann 8 1 4 4 Runaway Prevention ee 8 1 4 5 System Voltage L vels 2 2 e ale 10 E NEMI duae 11 1 5 1 EI MISTER TTE 11 1 5 2 IGICATIONS c 12 1 5 3 eruditi 13 16 cM ULIS LM EI E s 13 1 6 1 Site Nie Idcm Em 13 1 6 2 Network Operation Voltage Levels 13 ru gt mm 13 1 7 1 Relay Construction m 13 1 7 2 Terminal qaq 13 2 Performance 14 2 1 14 22 LO Ros en 14
6. 23 Voltage een 14 24 Map POSION iiti trud oM ee 14 25 Settings MANOS 14 2 6 anne 15 2 7 Output Contact Ratings EO omo 15 28 Environmental Withstand scene 15 16 4 installation 20 41 Unpacking Storage and Handling 20 4 2 Recommended Mounting 20 43 RET 20 44 AGONMOCHONS rise een 20 5 Commissionig terr 22 v2 0 Page 2 of 31 RTMU Control amp Monitor Relay 5 1 IU 22 5 2 eio c r 22 COMER oco E rcc 22 MEI cp 22 5 4 1 ISU ATION 22 55 RTMU cro Srv nee 22 5 5 1 Control Module PE 22 5 5 2 Tap Position Indicator 23 5 5 3 Voltage Monitor EP 25 6 Mini Talea 27 6 1 IUS Demo 27 LC EMI u ou see ee ee 27 6 2 1 Voltage Monitor Levels uu u uuu uuu 27 6 2 2 Buh a u ut UPO 27 6 2 3 Runaway 27 6 2 4 28 623 een Bn UND Mme 28 v2 0 Page 3 of 31 RTMU Control amp Monitor Relay Description of Operation 1 1
7. OR IP is detected before the internally generated reclaim time has expired The tap change has satisfied 3 above and a further tap position change will result in a lockout v2 0 Page 9 of 31 RTMU Control amp Monitor Relay NEXT CYCLE STARTS BEFORE RECLAIM TIME END TIME MA RAISE LOWER IN PROGRESS OPTIONAL LOCK OUT IP INDICATION Figure 5 Runaway condition The runaway prevention unit also protects against a runaway situation during push button operation Unwanted operations in manual control are prevented by avoiding further operations until the in Progress LED is extinguished Where apparent changes in tap position are seen i e a faulty high resistance sender unit contact Figure 6 shows how a lockout will not be initiated In this case no control signals are detected and as the mechanism is in a quiescent state a runaway is unlikely to occur The LCD display will mark the visible indication of tap position as suspect in this case until a further control signal initiates a tap change operation TEC POOR CONTACT RAISE LOWER IN PROGRESS OPTIONAL LOCK OUT Figure 6 Poor contacts no lockouts If because of the particular design of a tap change scheme raise lower and progress signals are not available during the tap change cycle monitor relays using tap positi
8. the low limit of normal voltage to be set 1 6 1 Site Arrangement It is necessary for the tap position indicator to be configured for the particular tap change mechanism The relays can be configured on site for the particular tap changer for further information see the commissioning section of this document 6 2 Network Operation Voltage Levels The operational settings of the voltage control system determine the normal range of voltage that will be expected at a site the high and low voltage monitor settings should be set in accordance with these levels Depending on the type of VT used the 3 phase monitor sensitivity will be set for the on site condition Where a 3 phase VT is installed a setting of 596 is normally selected unless the voltages are severely unbalanced where a 1096 selection is usually sufficient If a single phase VT is used for voltage sensing the voltage difference should be disabled 7 Hardware 71 Relay Construction The relay is housed in a mild steel case finished in oven baked powder coating The relay is mounted within the case on a semi withdrawable chassis which carries the complete assembly including the rear connector strips 7 2 Terminal Blocks At the rear of the relay terminal strips allow for all connections to the relay see also Figures 1 and 2 for connections lt 2 0 Page 13 of 31 RTMU Control amp Monitor Relay b m 7 rl 7 Performance Speci
9. 110 VAC CONTROL SUPPLY RTMU 1m 3 19 PULSE 20 DETECTION l LOCAL REMOTE AUTO MANUAL RAISE LOWER 23 10 t o lO O ol o 11 a 1 11 1 9 9 980 O NO ia 12 11 VOLTAGE INHIBIT Vet V HIGH V LOW 1 1 E ct s 11 15 16 17 18 1 MOTOR 1 vi VC RELAY CONTACTORS 11 Lx SUPPLY I mern 1 LIMIT OPERATING 055 OPEN E SWITCHES HANDLE DURING TAP ii A i INTERLOCK CHANGE mt 4 ra RAISE ni RAISE i ve NE 1 mt 11 j A 1 LOWER XE 1 LOWER T N ea ra 11 RAISE H x m zm 1 1 085 CLOSED STEP BY STEP LOWER DURING TAP CHANGE RTMU 1m MASTER LOCKOUT RELAY TRIP COIL j RUNAWAY PREVENTION 2 1 I 1 Figure 11 Typical tap change control circuit v2 0 Page 18 of 31 RTMU Control amp Monitor Relay RTMU RESISTOR TPI 25 1 038 27 I MOVING CONTACT 230 4 p 4 33 20 BCD TPI SWITCH Figure 12 Tap position indicator connections v2 0 Page 19 of 31 RTMU Control amp Monit
10. 1kV Series transverse mode lt 3 deviation Electrostatic Discharge 8kV contact discharge no maloperation Fast Transient 4kV 5 50us 2 5 repetitive lt 3 deviation Mechanical Classification Durability in excess of 10 operations v2 0 Page 15 of 31 3 Applications RTMU Control amp Monitor Relay Figure 9 to Figure 12 show some application drawings for a voltage control scheme incorporating the RTMU relay MAINTAINING SWITCH DRIVEN BY MECHANISM RAISE LOWER 0 fo Bie 10 llo 1 OPERATING RAISE LOWER HANDLE ISOLATOR OVERLOAD CONTACTOR CONTACTOR LIMIT SWITCHES INTERLOCK NA I Y 1 1 T 1 NE 1 POWER A Nr MOTOR SUPPLY 1 X 1 NE x I 1 MASTER RELAY TRIP COIL RUNAWAY PREVENTION Figure 9 Typical tap change motor circuit EGEGE Z ZZ ZZ GEF v2 0 Page 16 of 31 RTMU Control amp Monitor Relay TRANSFORMER UJ S1 S2 CT VT PHASE ROTATION A B C EARTHING O O O NOT SHOWN T VOLTAGE CONTROL RELAY RTMU RELAY RVM OR SUPERTAPP n Figure 10 VT and CT connections v2 0 Page 17 of 31 RTMU Control amp Monitor Relay
11. ET O MANUAL AUTO MONITOR LOW CONTROL EXTENT OF VISIBLE RETURN TO SITE AREA WITH COVER CENTRE OFF ON CONDITIONING REMOVED RTMU 2m SWITCHES Figure 8 RTMU Xm fascia 1 5 2 Indications Indications provided are shown Table 1 Table 1 Indications Function Colour Indication TAP IN PROGRESS Amber Operation of the tap changer via the Raise Lower In Progress contact or Tap Position LOCKOUT not RTPI 1m Red Invaid tap change operation HIGH RTMU Red System voltage is above a maximum level LOW RTMU Red System voltage is below a minimum level ALARM RTMU Red System voltage has remained at an abnormal level not zero for more than 15 minutes TAP POSITION LCD The current tap position v2 0 Page 12 of 31 RTMU Control amp Monitor Relay m 7 1 5 3 Controls Control Manual Auto A control switch is provided which allows the tap change control system to be operated under hand control or under the control of a voltage control relay 5 3 2 Manual Raise Lower When the control switch is set to manual this switch with a centre off position allows manual electrical control of the tap change mechanism 5 3 3 High A high setting adjustment is provided which allows the high limit of normal voltage to be set 5 3 4 Low A low setting adjustment is provided which allows
12. al a lockout relay is operated which can be used to disable the tap change motor 1 3 2 Voltage Monitor In automatic operation the voltage monitor continuously checks the output voltage of the power transformer and inhibits tap change operations which would cause the voltage to go above or below pre set maximum and minimum voltage levels If for any reason the maximum or minimum levels are exceeded instantaneous indication is provided followed by closing of an output contact after 15 minutes for a remote alarm All phases are monitored Any out of balance inhibits unwanted raise tap change operations for example those which could be caused by a blown H V voltage transformer fuse v2 0 Page 5 of 31 RTMU Control amp Monitor Relay N A A 1 1 ro 1 oh 1 NEUTRAL FOR R L amp IP DETECTORS BCD INPUT AVAILABLE ON REQUEST TAP POSITION RAISE POSITION CHANGE LOWER INDICATOR DETECTOR DETECTOR CONDITIONING SWITCHES IN PROGRESS LOGIC PROCESSOR DETECTOR VOLTAGE MEASURE 95 115 L 90 105 VOLTAGE LIMIT RAISE LOWER INHIBIT INHIBIT Figure 1 RTMU 1m block diagram v2 0 Page 6 of 31 N A EE RTMU Control amp Monitor Relay WN 2 NEUTRAL FOR R L amp DETECTORS TAP POSITION INDICATOR PROGRESS DETECTOR POSITION RAISE CHANGE LOWER DETECTOR DETECTOR CONDITIONING SWITCHES LOGIC PROCESSOR VOLTAGE MEASURE
13. d for the purposes of this document 5 3 Test Supplies A good quality rms sensing voltmeter and a variable output transformer can be used to confirm operation of the relay 4 Tests 5 4 1 Insulation It is an advantage to have an insulation resistance testing schedule It is usual to measure and record the insulation resistance section by section each section being defined by its supply sub fuse Insulation resistance can be measured before the supply fuses and links are inserted by testing from the load side of the fuse and link bases These tests should be carried out with all the wiring in a section shorted together therefore temporary connections will be needed to link in any wiring separated by normally open contacts etc While tests are being carried out on one section all other sections should be earthed using temporary connections Where particular circuits are normally earthed e g CT secondary circuits one earth link at a time should be removed to permit the testing of its associated circuits Replacement of the earthing links and the removal of all temporary connections including temporary earth connections should be confirmed by an entry in the insulation resistance testing schedule The insulation resistance values that should be considered to be acceptable depends upon the amount of wiring involved Where a considerable amount of multi core cabling is included a reading of 2 5 to 3 0 megohms is reasonable but for shorter len
14. d without a further genuine control signal being sent a lockout is initiated which can be arranged to disconnect supply to the tap change drive motor This applies to manual or automatically initiated electrical operations Some tap changers have transfer positions where more than one operation is required to complete a tap change In this event the unit can be configured to allow for transfer tapping v2 0 Page 8 of 31 RTMU Control amp Monitor Relay Lockout Logic For atap change to be correct the following sequence must take place as shown for a normal operation Figure 4 1 Acontrol signal must be sent to initiate the process 2 Thetap position must change to a new position 3 The tap change mechanism must stop completely On most schemes an In Progress IP auxiliary switch is also closed and used to indicate the operation of the mechanism the operation of this contact is also shown To confirm correct operation of the runaway logic a definite break between successive tap change operations must be detected as indicated by the reclaim time in Figure 4 to Figure 6 OPERATION RECLAIM TIME RAISE LOWER C F ia i PM L _ 0 L OPTIONAL LOCK OUT IP INDICATION Figure 4 Normal operation For an incorrect tap change Figure 5 where the mechanism over runs or continues to operate a new control signal AND
15. e Runaway Prevention Unit should lock out soon after the first complete tap change operation depending upon the tap change operating time Repeat for the lower direction lt 2 0 Page 27 of 31 RTMU Control amp Monitor Relay For very fast tap change mechanisms more than one tap change operation may occur before the lockout operates In this case great care should be exercised if the test is carried out with the transformer on load 6 2 4 Alarms Operate a tap changer to lockout and check operation of alarm contacts after 15 minutes 6 3 Completion On completion of tests all settings can be returned to normal v2 0 Page 28 of 31 RTMU Control amp Monitor Relay Notes RTMU Control amp Monitor Relay RTMU Control amp Monitor Relay
16. e detection SW1 sw2 SW3 SW4 SW5 SW6 SW7 SW8 Disable Enable Table 6 Switch settings for voltage difference sensitivity SW1 sw2 SW3 SW4 SW5 SW6 SW7 SW8 10 5 Set basic control to force RVM relay to raise voltage Confirm raise control signals are blocked Page 26 of 31 RTMU Control amp Monitor Relay 6 1 Introduction Voltage control systems are continually operative when in service Any deviations in accuracy and control will directly affect the customers connected to the controlled power system The SuperTAPP n voltage control system has been designed with reliable voltage control circuitry with continuous separate monitoring of the resultant system voltage including the voltage transformer Minimal checks can be carried out on the relay during operation to confirm correct operation Maintenance of equipment should be carried out only by skilled personnel trained in relay operation and capable of observing all the necessary safety precautions and regulations appropriate to this equipment and also the associated primary plant Ensure that all test equipment and leads have been correctly maintained and are in good condition No specialist test equipment is required 6 2 As the tests can be best carried out with the transformers l
17. ete type Where the relay is used with a suffix type tap changer the sender unit resistor or BCD should be arranged to send the same signal for each of the suffix positions and SW6 should be set to Off normal Resistor types should have the appropriate resistors on the sender unit shorted out see Figure 15 7 8A 8B 8C 9 Figure 15 Shorting out sender unit resistors Where the relay is used with a tap change having discrete transfer positions this switch should be set to On transfer The relay is normally supplied to allow for two discrete transfer tap change operations per control signal Replacement controller IC s are available on request for nonstandard schemes including BCD with an even number of taps and Discrete types with more than 2 consecutive transfer operations Table 4 Switch settings for type of tap change SWi SW2 SW3 SW4 SW5 SW6 SW7 SW8 Transfer TPI Operation Operate the tap changer to the highest tap position and confirm correct indications If the transformer cannot be taken out of service the top tap position can conveniently be simulated by temporarily disconnecting the wire going to terminal 26 and then shorting 26 to 27 After replacing any temporary connections check the indication through the full range of the tap changer if possible v2 0 Page 24 of 31 RTMU Control amp Monitor Relay In the unlikely event that satisfac
18. fication 2 1 Introduction Performance to IEC255 3 2 2 Power Supply Auxiliary Supply 110V or 220Va c Range 45 140 Burden 3VA 2 3 Voltage Transformer Rated voltage 60V to 140V true rms default 110V rms Burden 3VA 4 Tap Position Resistor Sender Minimum value of each resistor 10 ohms Maximum value of each resistor 470 ohms Recommended value 100 ohm 1 Watt 1 BCD Sender Bit weighting 1 2 4 8 10 20 Binary Bit weighting 1 2 4 8 16 32 5 Settings Range High Voltage limit 95 115 continuously adjustable Low Voltage limit 90 105 continuously adjustable Voltage difference Disable 5 or 10 Number of taps 11 to 41 in Resistor mode or 11 to 39 in BCD mode Transfer tap position 2 each side of mid position or any arrangement by request Alarm 15 min ee Page 14 of 31 RTMU Control amp Monitor Relay 2 6 Accuracy High Voltage limit 1 Low Voltage limit 1 Voltage Difference 10 at 5 setting 15 at 10 setting Alarm 15 min 10 sec 2 7 Output Contact Ratings Lockout V high and V low 10A 240V AC maximum 450mA 110V DC maximum Alarm 240V maximum 450mA 110V DC maximum 2 8 Environmental Withstand Temperature Operating range 10 to 506 Storage range 25 70T Transient Overvoltage Between all terminals and earth or 5kV 1 2 50us between any two terminals High Frequency Disturbance 2 5kV Common longitudinal mode lt 3 deviation
19. gths of panel wiring higher readings should be expected A reading 1 0 megohm or less should not be considered satisfactory and should be investigated 5 5 RTMU Relays 5 1 Control Module The module may be panel mounted or rack mounted as required A check should be made to ensure that the tap changer functions correctly for both automatic and manual operations lt 2 0 Page 22 of 31 RTMU Control amp Monitor Relay 5 5 2 Position Indicator Three connections are required to a remote resistance type sender unit Please note that on some older types of control circuit the 110V AC supply may have been connected directly across the remote sender unit and in this case it must be removed before connecting the new unit For older units it is recommended that the opportunity is taken to clean and lubricate the contacts of the remote sender unit particularly if the Runaway Prevention feature is to be used Conditioning The site conditioning switches are located at the bottom right of the RTMU fascia plate see Description of Operation section of this document and are arranged as shown in Figure 14 SW1 SW8 1 Maximum Position For calculation of the actual tap position SW1 to SW4 must be set for the maximum number of taps for the particular tap changer If the tap changer has an even number of taps with a resistor type sender unit an extra resistor should be inserted at the top of the resistor chain a
20. her to B the alarm timer is initiated the voltage control relay if operating correctly will initiate a lower tap change operation and the system voltage will be changed to C before the alarm time out is exceeded and the timer is reset As the system voltage reduces to D the raise blocking contacts are released allowing raise tap change operations to take place if needed The reverse action takes place if the system voltage drifts in the lower direction Unlike the voltage control relay which uses two of the three available voltage transformer VT phase voltages for measurement purposes the voltage monitor uses all phases and detects any voltage difference between phase voltages as a check against VT HV or LV fuse failure If a difference is detected the monitor will inhibit tap change raise operations but allow lower operations 1 5 User Interface 1 5 1 General 5 The design of the relay fascia plate is user friendly each function is shown as a set of logical functions organised to be easily understood Fascia plate arrangements for the RTMU 1m and RTMU 2m relays are shown in Figure 8 v2 0 Page 11 of 31 RTMU Control amp Monitor Relay TPI A D VOLT MONITOR TAP IN PROGRESS TAP CHANGE MANUAL zt CALIBRATION CONTROL UNIT Type RTMU XM FUNDAMENTALS LTD fundamentalsltd co uk LOWER RAISE TAP POSITION LOCKOUT VOLTAGE F RES
21. nd the switch selected for Max 1 Figure 14 Site Conditioning Switch Table 2 Switch settings for maximum tap position Number of Taps SW1 SW2 SW3 SW4 SW5 SW6 SW7 SW8 11 13 15 17 19 lt gt eu EC CO EC N 0 0 0 0 0 0 0 0 00 00 00 00 0000 0000 v2 0 Page 23 of 31 RTMU Control amp Monitor Relay Type of Sender Unit Set SW5 according to the type of sender unit resistor or binary coded decimal BCD Table 3 Switch settings for type of sender unit SW1 SW2 SW3 SW4 SW5 SW6 SW7 SW8 Resistor BCD Some tap changers have transitional tap positions where more than one operation is carried out for single raise or lower control signal Furthermore some tap changers have these transfer positions indicated as say 8A 8B amp 8C where positions 8B and 8C are not used for voltage change For the same effect another tap changer may have positions 8 9 amp 10 where 8 amp 10 are not used for voltage change To clarify the types of transfer tap changers those with suffix letters A B C etc are termed suffix type those with discrete numbers e g 8 9 10 are termed discr
22. ng the formula Basic Voltage Full Load LDC Boost Upper Bandwidth 1 2 for safety Similarly the low setting formula is Basic Voltage 6 Load Shed Lower Bandwidth 1 2 for safety e g With a 100 basic setting 5 LDC setting and plus minus 1 5 band width setting the high setting would be 107 and the low setting 92 The raise and lower inhibit relays are automatically set to operate 2 before the Alarm settings thus preventing the tap changer from operating in a direction which would cause the voltage to go outside the alarm limits Checking for Correct Operation The voltage monitor can be checked using a variable test supply and an accurate voltmeter The voltage difference feature will need to be disabled The High and Low LED s will indicate when the alarm settings are reached During this test the proper functioning of the inhibit circuits and 15 minute alarm can also be checked Voltage Difference SW7 should be set for phase voltage difference detection SW8 determines the voltage difference sensitivity The correct operation of the voltage difference detector can be confirmed by removal of the VT fuse which does not supply the accompanying voltage control relay SuperTAPP n or RVM In this case the voltage monitor will block any raise control signals v2 0 Page 25 of 31 RTMU Control amp Monitor Relay v2 0 Table 5 Switch settings for phase voltage differenc
23. oad care should be taken to ensure that no operation of the tap changers can take place when settings are changed As settings will be changed for testing purposes the operational levels should be noted prior to testing 6 2 1 Voltage Monitor Levels Use a good quality rms measuring voltmeter to measure the incoming voltage transformer level Move High monitor level control until High Indication move High monitor level control until Low Indication Check that the two settings are within 1 296 of the measured voltage 2 2 Difference The correct operation of the voltage difference detector can be confirmed by removal of the VT fuse which does not supply the voltage control relay In this case the voltage monitor will block any raise control signals Set basic control to force the voltage control relay to initiate a raise operation Confirm raise control signals are blocked 2 3 Runaway Prevention Checking for Normal Operation Operate the tap changer in the raise direction and observe the normal correct operation of tap changer Immediately the in Progress LED goes off operate the tap change once more in the same direction and again observe correct operation Repeat for the lower direction Checking for Lockout Carry out a raise operation but this time simulate a potential runaway condition by permanently energising the raise or lower contacts or alternatively repeated operation of the tap change control switch Th
24. on logic only for runaway prevention can be supplied to specific order 1 4 5 System Voltage Levels The voltage monitor checks the maximum and minimum levels of system voltage each level being dependent upon the settings applied to the voltage control relay For security the voltage monitor settings and measurement circuits are not included in the accompanying voltage control relay SuperTAPP n or RVM The voltage level is monitored for valid upper and lower limits The limits beyond which the system voltage should not persist is set by the voltage control relay settings i e Basic LDC and V Offset Active blocking of Raise or Lower control signals takes place automatically 2 within the upper and lower alarm limits v2 0 Page 10 of 31 RTMU Control amp Monitor Relay To clarify the action of the voltage monitor refer to Figure 7 When the system voltage moves to point a raise blocking contact is opened As the voltage is now within 2 of the normal upper limit the voltage control relay should not correctly request a raise operation UPPER ALARM B LEVEL 7 H 1 7 i BAND AT 77 Isa FULL LOAD UPPER BLOCKING 777 gt Sea lt 7 24 LEVEL lt gt A D lt VOLTAGE DEVIATION LOWER BLOCKING LEVEL BAND AT NO LOAD V Red LOWER ALARM LEVEL Figure 7 Voltage monitor blocking and alarm As the system voltage increases furt
25. or Relay 4 Installation 4 1 Unpacking Storage and Handling On receipt unpack the relay and inspect for any obvious damage It is not normally necessary to remove the relay from its wrapping unless some damage is suspected or if it is required for immediate use If damage has been sustained a claim should immediately be made against the carrier also inform Fundamentals Ltd When not immediately required return the relay to its carton and store in a clean dry place Equipment should be isolated from auxiliary supplies prior to commencing any work on an installation 4 2 Recommended Mounting Positions The use of the SuperTAPP n relay and RTMU monitor relay allows a complete voltage control system to be contained in a 19 inch rack at 4U height The mounting of two relay systems in a cubicle allows two transformers to be operated in parallel providing an economic use of space The relays are normally mounted flush to the panel front using either a sub rack in a rack cubicle or 4mm screws when mounted directly in custom slots The diagrams at the end of this section give details of case size and fixing dimensions 43 Relay Dimensions Details of the key relay dimensions are shown in Figure 13 1 Standard 19 rack 2 4mm screws 4 Connections All connections are made using the supplied 4BA pan head screws each connector point allows a maximum crimp terminal width of 7 5mm v2 0 Page 20 of 31 RTMU Control amp Monitor Relay
26. r tap change operations in the wrong direction when connected into the raise and lower contactor initiation circuits Alarm An output relay with a normally open contact is provided for external alarm if a tap change runaway or voltage abnormality is detected after a time delay For general use the RTMU 1m relay is available to meet the requirements of standard tap change schemes The RTMU 2m relay has modified Auto Manual with return to centre off position control switch for use with some systems lt 2 0 Page 4 of 31 RTMU Control amp Monitor Relay Figure 1 and Figure 2 are block diagrams of the relay functional structure 1 3 4 Tap Position Indication The tap position is indicated by a liquid crystal display LCD driven via a filtered input circuit from a resistor type sender unit A digital input circuit is additionally available as standard on the RTMU 2m or as an option on the RTMU 1m This can be either binary coded decimal BCD or true binary If used with a resistor sender unit the tap position indicator will read the correct tap position regardless of the number of taps or the resistor values within the limits set see specification Underlying the tap position indicator is the runaway prevention logic where detection of raise or lower signals is used to determine the valid operation of the tap change mechanism If a tap change operation takes place without a previous raise or lower tap change initiation sign
27. tory calibration cannot be obtained the sender unit resistors should be replaced Suitable resistors are 1000hm 1Watt 1 tolerance metal film resistors Checking for Normal Operation Operate the tap changer in the raise direction and observe the normal correct operation of tap changer Immediately the in Progress LED goes off operate the tap change once more in the same direction and again observe correct operation Repeat for the lower direction Induced voltages on quiescent raise lower and In Progress wiring can if excessive power the In Progress LED The application of a 0 22uF mains suppression capacitor between the relevant input terminals and neutral of the RTMU relay will attenuate these false signals Checking for Lockout Carry out a raise operation but this time simulate a potential runaway condition by permanently energising the raise contactor or alternatively by repeated operation of the tap change control switch The runaway prevention Unit should lock out soon after the first complete tap change operation depending on the tap change operating time Repeat for the lower direction For very fast tap change mechanisms more than one tap change operation may occur before the lockout operates In this case great care should be exercised if the test is carried out with the transformer on load 5 5 3 Voltage Monitor Determination of high and low alarm settings is shown below The High setting is calculated usi
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