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R8140B | Relay | Transformer
R8140B
Uploaded by azminord
TYPE MHOA 04, MHOB 04, MHOC 04
Translay Feeder Protection Schemes
2 3.1 3.6 3. 4.5.1 3. 2.2 3.5 3. COMMISSIONING TEST RECORD REPAIR FORM 17 18 19 19 20 20 21 21 22 22 23 24 25 26 27 29 33 Page 4 .3 3.1 3.3 3.1.5 3. 3.2 3. 2.7.1 3.3 2.CONTENTS SAFETY SECTION 1.4 3.1 5.3.1.4 3.1.1 2.3.5. INTRODUCTION INSTALLATION General Unpacking Storage Site COMMISSIONING Commissioning preliminaries Inspection Wiring Earthing Insulation Electrical tests Current transformer tests Ratio test Magnetisation curve test Polarity test (dc flick test) Phasing tests Relay setting tests Relay stability tests MHOB and MHOC relays MHOA relay Pilot loop resistance Trip circuit The commissioning instructions for the MRTP01 are given below: Adjust as follows: MAINTENANCE Routine tests COMPATIBILITY 5 9 9 9 9 10 10 10 10 10 10 11 11 11 11 11 12 12 12 12 13 13 13 14 14 14 15 16 16 17 Table 1: Nominal relay settings Table 2: Current transformer requirements Figure 1: Current transformer ratio test Figure 2: Current transformer magnetisation curve test Figure 3: Current transformer dc flick test Figure 4a: Single phase injection Figure 4b: Two phase injection Figure 5a: Relay setting test using primary injection – earth fault A–N Figure 5b: Relay setting test using primary injection – phase fault A–B Figure 6: Stability test using primary injection test set through A–B phase fault Figure 7: Stability test using phase load current – through A–N earth fault Figure 8: Type MHOA/HOA4 plain feeder protection Figure 9: Type MHOB/HOB4 plain feeder protection Figure 10: Type MHOC/HOC4 plain feeder protection Figure 11: MRTP connections with a Translay scheme 6.2 4.7 3.4 3.1.4 3.7.2 2.3.1 3.2 3.3.
Installing. It is assumed that everyone who will be associated with the equipment will be familiar with the contents of the Safety Section. power supply. Terminals exposed during installation. Page 5 . Commissioning and Servicing Equipment connections Personnel undertaking installation. the correct crimp terminal and tool for the wire size should be used. Caution: refer to product documentation Caution: risk of electric shock Protective/safety *earth terminal Functional *earth terminal. Note: this symbol may also be used for a protective/ safety earth terminal if that terminal is part of a terminal block or sub-assembly eg. If there is unlocked access to the rear of the equipment. Health and safety The information in the Safety Section of the product documentation is intended to ensure that products are properly installed and handled in order to maintain them in a safe condition. commissioning or servicing the equipment. To ensure that wires are correctly terminated. *Note: The term earth used throughout the product documentation is the direct equivalent of the North American term ground. Voltage and current connections should be made using insulated crimp terminations to ensure that terminal block insulation requirements are maintained for safety. is given below. commissioning or servicing work on this equipment should be aware of the correct working procedures to ensure safety. care should be taken by all personnel to avoid electric shock or energy hazards. commissioning and maintenance may present a hazardous voltage unless the equipment is electrically isolated. Explanation of symbols and labels The meaning of symbols and labels which may be used on the equipment or in the product documentation.SAFETY SECTION This Safety Section should be read before commencing any work on the equipment. The product documentation should be consulted before installing.
Current transformer circuits Do not open the secondary circuit of a live CT since the high voltage produced may be lethal to personnel and could damage insulation. these should not be viewed directly. External resistors Where external resistors are fitted to relays. Battery replacement Where internal batteries are fitted they should be replaced with the recommended type and be installed with the correct polarity. Integrity of earth connection (where applicable) Equipment operating conditions The equipment should be operated within the specified electrical and environmental limits. if touched. these may present a risk of electric shock or burns. Fibre optic communication Where fibre optic communication devices are fitted. CT circuit rating and integrity of connections. Before energising the equipment.Before energising the equipment it must be earthed using the protective earth terminal. to discharge capacitors. the following should be checked: Voltage rating and polarity.5 mm2. or the appropriate termination of the supply plug in the case of plug connected equipment. to avoid possible damage to the equipment. Page 6 . Insertion of modules and pcb cards These must not be inserted into or withdrawn from equipment whilst it is energised. Protective fuse rating. Optical power meters should be used to determine the operation or signal level of the device. Omitting or disconnecting the equipment earth may cause a safety hazard. unless otherwise stated in the technical data section of the product documentation. since this may result in damage. The recommended minimum earth wire size is 2. At the end of each part of the test. before the test leads are disconnected. Insulation and dielectric strength testing Insulation testing may leave capacitors charged up to a hazardous voltage. the voltage should be gradually reduced to zero.
to avoid any risk of electric shock. this should not be inserted or withdrawn from the equipment whilst it is energised. CT shorting links must be in place before insertion or removal. This is to avoid possible shock or damage hazards. Insertion and withdrawal of extender cards When using an extender card. Particular regulations within the country of operation. to avoid any risk of electric shock. taking precautions to avoid short circuits. Mechanical adjustments The electrical power to the relay contacts should be removed before checking any mechanical settings. the capacitors should be safely discharged via the external terminals prior to decommissioning.may apply to the disposal of lithium batteries. It is recommended that incineration and disposal to water courses is avoided. may expose hazardous live parts such as relay contacts.Older Products Electrical adjustments Equipments which require direct physical adjustments to their operating mechanism to change current or voltage settings. Draw out case relays Removal of the cover on equipment incorporating electromechanical operating elements. To avoid electric shock or energy hazards. Disposal: Page 7 . to avoid potentially lethal voltages. Any products containing batteries should have them removed before disposal. Decommissioning and Disposal Decommissioning: The auxiliary supply circuit in the relay may include capacitors across the supply or to earth. after completely isolating the supplies to the relay (both poles of any dc supply). Insertion and withdrawal of heavy current test plugs When using a heavy current test plug. should have the electrical power removed before making the change. The product should be disposed of in a safe manner. Hazardous live voltages may be accessible on the extender card.
fixed installation. 0. Installation Category (Overvoltage): Environment: IEC 61010-1: 1990/A2: 1995 Pollution degree 2 EN 61010-1: 1993/A2: 1995 Pollution degree 2 73/23/EEC Product safety: EN 61010-1: EN 60950: Page 8 . between all supply circuits and earth and also between independent circuits.5J. Equipment in this category is qualification tested at 5kV peak. Compliance with the European Commission Low Voltage Directive. Distribution level. unless otherwise stated in the technical data section of the product documentation.Technical Specifications Protective fuse rating The recommended maximum rating of the external protective fuse for this equipment is 16A. Insulation class: IEC 61010-1: Class I EN 61010-1: Class I IEC 61010-1: Category III EN 61010-1: Category III 1990/A2: 1995 1993/A2: 1995 1990/A2: 1995 1993/A2: 1995 This equipment requires a protective (safety) earth connection to ensure user safety. 1993/A2: 1995 1992/A11: 1997 Compliance is demonstrated by reference to generic safety standards.2/50µs. Red Spot type or equivalent. Compliance is demonstrated by reference to generic safety standards. 500Ω. 1.
especially where the pilot wires are in close proximity to power conductors. Section 2. although generally of robust construction. At all times handling must be by skilled persons only. Particular attention should be given to the pilot wire circuits statement. the performance of current transformers and relays is capable of giving the expected results. Translay protection schemes have been well proven under the most arduous operating conditions in all parts of the world. however. It is usually not feasible to reproduce actual fault conditions. The relays are either despatched individually or as part of a panel/rack mounted assembly in boxes specifically designed to protect them from damage.1 General Protective relays. a claim should be made to the transport company concerned immediately. Stability to external faults is equally as important as operation for internal faults but it is more difficult to test under actual operating conditions. Therefore elaborate site testing is unnecessary. If damage due to transit is evident. Relays which are supplied unmounted and not intended for immediate installation should be returned to their protective polythene bags. so it cannot readily be tested under actual operating conditions as can other forms of electrical plant. By observing a few simple rules the possibility of premature failure is eliminated and a high degree of performance can be expected. Translay relays are designed to withstand such voltages. require careful treatment prior to installation and a wise selection of site. INTRODUCTION Protective equipment is solely concerned with fault conditions. Under fault conditions considerable voltages may be induced in pilot wires. These voltages are relative to earth. Page 9 . 2. and the nearest AREVA T&D representative should be promptly notified. Periodic routine tests are designed to verify the integrity of the relays to prove that they have not been damaged. INSTALLATION Before carrying out any work on the equipment the user should familiarise himself with the contents of the Safety Section. and no components have been damaged in transit or during installation. 2. The peak of these voltages may rise momentarily to some thousands of volts. The object of commissioning tests is to ensure that all connections of the protection scheme are correct. to ensure satisfactory operation of the protection it is desirable to keep the pilots clear from earth and to avoid connecting them to auxiliary switches or other items that may have inadequate insulation strength.Section 1. Many forms of protective equipment remain stable when faults occur outside the zone of protection. Relays should be examined immediately they are received to ensure that no damage has been sustained in transit.2 Unpacking Care must be taken when unpacking and installing the relays so that none of the parts are damaged or settings altered.
Section 3. find its way into the relay.1. The site should preferably be well illuminated to facilitate inspection. An outline diagram is normally supplied showing panel cutouts and hole centres.3 Storage If relays are not installed immediately upon receipt they should be stored in a place free from dust and moisture in their original boxes and where dehumidifier bags have been included in the packing. For individually mounted relays these dimensions will also be found in publication R6140. on subsequent unpacking. 2. It is essential that such switches are fitted across all CT circuits. This document will be useful when individual relays are to be assembled as a composite rack or panel mounted assembly. Page 10 . The action of the dehumidifier crystals will be impaired if the bag has been exposed to ambient conditions and may be restored by gently heating the bag for about an hour. COMMISSIONING Before carrying out any work on the equipment the user should familiarise himself with the contents of the Safety Section.2 Wiring Check that the external wiring is correct to the relevant relay diagram and scheme diagram.4 Site The installation should be clean. Dust which collects on a box may. dry and reasonably free from dust and excessive vibration. 3. Note: The shorting switches shown on the relay diagram are fitted internally across the relevant case terminals and close when the module is withdrawn. Relays which have been removed from their cases should be left in a dust and damp free environment. 3. This particularly applies to installations which are being carried out at the same time as constructional work. Carefully remove any elastic bands/packing fitted for transportation purposes.1 3. The storage temperature range is -25°C to +70°C. they should be retained. 2.Relays should be examined for any wedges. in damp conditions the box and packing may become impregnated with moisture and the dehumidifying agent will lose its efficiency. case and cover are identical and that the model number and rating information are correct. The relay diagram number appears inside the case.1 Commissioning preliminaries Inspection Carefully examine the module and case to see that no damage has occurred during transit. These should be removed after installation and before commissioning. Check that the serial number on the module. Particular attention should be given to the pilot wire circuits statement. clamps or rubber bands necessary to secure moving parts to prevent damage during transit.1. R7012 is a Parts Catalogue and Assembly Instructions Publication. prior to replacing it in the box.
When type MMLG test block facilities are installed. 3. however. which correspond to the current transformer secondary windings.1 Current transformer tests Ratio test Inject current into the primary of the A (red) phase current transformer and measure the current in the secondary winding. 3.1. an MMLB 02 single finger test plug must be terminated with an ammeter BEFORE IT IS INSERTED to monitor CT secondary currents. having a dc voltage not exceeding 1000V.5 Insulation The relay and its associated wiring may be insulation tested between: • all electrically isolated circuits • all circuits and earth An electronic or brushless insulation tester should be used. The ratio between the primary and secondary currents will be approximately equal to the turns ratio of the current transformer. Refer to Figure 1. REFER TO THE SAFETY REQUIREMENTS OF THE COUNTRY OF INSTALLATION. SUITABLE PRECAUTIONS SHOULD BE TAKEN BEFORE HANDLING PILOT WIRES.2 Electrical tests DANGER: DO NOT OPEN CIRCUIT THE SECONDARY CIRCUIT OF A CURRENT TRANSFORMER SINCE THE HIGH VOLTAGE PRODUCED MAY BE LETHAL AND COULD DAMAGE INSULATION. the procedure is generally correct. FOR SAFE HANDLING OF PILOT WIRES. This should be repeated for the current transformers in the B (yellow) and C (blue) phases.4 Earthing Ensure that the case safety earth connection at the top of the rear terminal block is used to connect the relay to a local earth bar. Similarly. the difference being equal to the magnetisation current taken by the current transformer. THESE CAN RISE TO A LETHAL HIGH VOLTAGE RELATIVE TO THE GROUND POTENTIAL UNDER LINE FAULT CONDITIONS. The instructions have been written assuming that not all schemes are fitted with a test block. it will be necessary to determine the appropriate test block terminals for applying the voltages and monitoring relay operation from the scheme diagram. Where a test block is used. the connections are made to the live side of the test block (coloured orange with odd terminal numbers). it is important that the sockets in the type MMLB 01 test plug.If the test block type MMLG is provided. are LINKED BEFORE THE TEST PLUG IS INSERTED INTO THE TEST BLOCK. 3. Page 11 .3 3.1. Accessible terminals of the same circuit should first be strapped together.3. 3. The auxiliary supply voltage to the scheme should be routed via test block terminals 13 and 14.
3. B and C phase currents will be the same with negligible current flowing in the neutral ammeter. the primary winding is energised and the dc milliammeter should give a momentary positive deflection. the milliammeter should give a momentary negative deflection. A dc milliammeter of the moving coil permanent magnet.2 times higher than the nominal relay settings due to the current transformer magnetisation current. in series with a single pole switch. is connected across the primary winding. A more convenient method of phasing out is by using the primary balanced load current. refer to Figure 4a. For correct phasing. When the primary winding is deenergised.4 Relay setting tests The following tests are applicable for MHOA. For correct phasing the current reading of the A phase and neutral ammeters will be the same with negligible current in the B & C phase ammeters. 3.4 Phasing tests Inject current into the primary of the A phase CT. The tests are carried out by raising the test current until the relay operates. Secondary injection of current may be used to check the relay settings if insufficient current is available by primary injection. Avometer set to DC mA. C-N and checking the current values. This test should be repeated by injecting across the A & C phase. Refer to Figure 2. Other checks which should be carried out are: • check flag operate/reset • check CT shorting switches • check contact operation Page 12 . This should be repeated for the B and C phases. The arrangements for checking the relay settings are similar to those required for current transformer polarity tests using a primary injection test set. refer to Figure 4b. Refer to Figure 3. If higher settings are required the torsion head may be rotated to achieve it at this time. For correct phasing the current reading of the A & B phase ammeters will be the same with negligible current in the C phase and neutral ammeters.2 Magnetisation curve test The magnetisation curve of all current transformers should be checked at the minimum number of points necessary to identify the current transformer and to determine its suitability for the intended duty.3. Nominal relay settings are shown in Table 1 at the end of this publication but the effective settings will normally be 1. During these tests the torsion head on the relay should be set to the minimum setting mark. 3. If one CT was reversed then approximately twice phase current will appear in the neutral ammeter. MHOB and MHOC relays. Refer to Figures 5a and 5b.1 to 1. 3. Where a centre zero ammeter is not available a moving coil multi-meter should suffice eg. centre zero pattern is connected across the secondary winding and a low voltage battery. Inject primary current across A & B phases with a primary short on the other side of the CT.3. by opening the switch. This is equivalent to a single end feed condition. the A.3 Polarity test (dc flick test) All current transformers should be tested to confirm that the primary and secondary polarity markings are correct. On closing the switch.3. In addition the torsion head settings should be checked by injecting on one phase.
5.5.2.5 Relay stability tests These stability tests can be considered conclusive ONLY if the phasing tests at each end of the scheme have been performed beforehand. Apply a test current equal to the rating of the current transformer and record the pilot voltage and current.5. Refer to Figure 7. The above test should be repeated for B and C phases. 3. The test procedure for the MHOA.2 MHOA relay 3.5. These tests should now be repeated for the B phase with the A and C phase current transformers disconnected and shorted and also for the C phase with the A and B phase current transformers disconnected and shorted. This should be repeated for the B phase with A and C phase current transformers disconnected and shorted and also for the C phase with the A and B phase current transormers disconnected and shorted. apply load current between ends A and B only. The current reading should not exceed 10mA and the relay should remain stable. Page 13 . Repeat this test with the pilot wires reversed and check that the current in the pilot millammeter increases and the relay operates or tends to operate depending upon the value of test current.3. the increased line impedance may make it impossible to produce sufficient current for the above test. Refer to Figure 6.1 Inject primary current at end A across A and B phases with a primary short circuit across the phases at end B after the current transformers. From these tests definite pilot wire polarity may be proved. 3.5.2.5. noting that the relay restrains or tends to restrain.1 MHOB and MHOC relays 3.2 The following tests should be carried out using primary load current. The tests for the MHOA are carried out in a slightly different manner. If a current equal to the primary rating of the current transformer cannot be obtained then the actual primary current should be recorded. reversal of the pilots will be indicated by an increase in the current in the pilot wire ammeter and a tendency for the relay to operate.1. The test should also be repeated for B and C phases.1. In such cases it will be necessary to perform the test described in Section 3. These tests should then be repeated between ends B and C with test current injected at end B and the primary short circuit at end C only and again between C and A with test current injected at end C and the primary short circuit at end A only. In the case where the test current is less than the effective relay setting. This test is now repeated with the pilot wire reversed.1. The above test should be carried out between A and B phases as shown in Figure 6. Where these relays are applied to a long section of line.1 For a 3 ended system the stability tests should be carried out between ends A and B with test current injected at end A and the primary short circuit at end B only. 3. energise the system and record the pilot voltage and current for future reference. With the A phase current transformers only connected in circuit and the B and C phase current transformers disconnected and shorted at each end of the feeder.2 With only A phase current transformers connected in circuit and B and C phase current transformers disconnected and shorted at all the ends of the scheme.2.5. MHOB and MHOC relays is given below. 3.
Apply the appropriate ac supply for the supervision circuit and the normal dc supply. Failure to reset is almost invariably due to the absence of correct ac or dc supplies. The latter is primarily intended as an aid during the setting of the adjustable resistor marked SET. and again between ends C and A. 3. It is recommended that 250V grade pilot wires are used. For the MHOB 04 and MHOC 04 relays the maximum recommended loop resistance is 1000Ω with a maximum intercore capacitance of 3µF. If any of these indicators are operated. Operate the disc manually using an insulated tool. The top red LED is to indicate failure of the ac supervision supply. Adjustment is made by a worm drive screw which is connected directly to a resistor. This current should be approximately 1. and is the current flowing in the pilots. The MRTP01 will provide supervision at the local end while an MRTP02 can be used at the remote end. 3.1 The commissioning instructions for the MRTP01 are given below: Monitor the current which should flow in the pilot using a dc milliammeter. There are three red LED indicators and a green LED indicator. When correctly connected and energised from the appropriate ac supply voltage the relay will inject a dc supervision supply across a capacitor in series with the pilots. 3. If pilot supervision is required with the MHOB or MHOC relay then MRTP01 and MRTP02 relays can be used. Reclose the circuit breaker after the test. the ac supervision supply fail indicator should reset when the reset push button is pressed. These relays are suitable for pilot isolation up to 4kVrms for 1 minute.7 Trip circuit With primary load current flowing in the feeder and the pilots correctly connected. For the MHOA 04 relay the maximum recommended loop resistance is 400Ω with a maximum intercore capacitance of 1mF. using a digital voltmeter. resetting should be attempted by pressing the reset button. Assuming that the ac and dc supplies are present. The middle red LED indicator is to indicate pilot fail open circuit whilst the lower one is to indicate pilot fail short circuit. Note the reading on the dc milliammeter. To facilitate the setting of the pilot supervision there is a test push button Page 14 . If 15kV isolation is required then an MBCI translay scheme is recommended. This allows for a fine adjustment in the relay calibration.The above test should be repeated with load current applied between ends B and C. a trip should be initiated and the circuit breaker should open. For systems which have 4 ends or more the tests should be carried out in a similar manner.6 Pilot loop resistance Short out the pilot at the remote end of the line at the relay terminals and measure the pilot loop resistance at the local end of the line at the relay terminals.2mA dc. the relay should be restraining.7. This procedure should be repeated at the other end of the feeder. The adjustable resistor is changed by the use of a small screwdriver through a hole in the front plate marked SET. In either case set the adjustable resistor as detailed in the following tests. The following tests are applicable if MRTP relays are used. The pilot fail indicators may be in the operated or reset state.
CT shorting links removed and tripping tests carried out on the circuit breakers from the relays. It is advisable to check that if the pilots are open circuit. turn it clockwise for 30 complete turns. The meter must be suitably set either to measure volts. where the contacts have not opened. Release the test button. The dc supply should also be checked. Turn the screwdriver clockwise by half the number of turns counted previously. or ohms if there are no other connections to the terminals. Turn the screwdriver anticlockwise until either the green LED goes out and the contacts open or the worm drive has been turned 30 complete turns. Depress the test button again. the green LED comes on instantaneously and the pilot fail short circuit indicator operates after approximately 10 seconds. The contacts should also close. Depress the test button (which closes the supervision zone). Reset the pilot fail circuit red LED. After restoring the pilots to normal. If it is considered desirable to monitor the position of the normally open contact of the pilot fail relay. In the latter case.2mA dc and is the current flowing in the pilots (a low dc current in the pilots indicates that the pilot resistance is much higher than the limit of 1000 ohms). After restoring the pilots to normal. if the circuits are live.2 Adjust as follows: With the screwdriver engaging the worm drive of the SET resistor. Release the test button. The pilot supervision is now correctly set. Page 15 . With the test button held depressed. On completing the tests all trip links should be restored.7. Keeping the test button depressed. Check that if the pilots are short circuit. the green LED should not illuminate. counting the number of turns until the green LED comes on again. Replace the relay cover and press the reset button. Approximately 5 seconds after restoration of the ac supply it should be possible to reset the supervision supply fail indicator. 3. If the green LED is out and the contacts open. check that the dc and ac supplies are present. Disconnect the milliammeter from the pilots and restore pilot connections. check the reading on the dc milliammeter. This current should be approximately 1. reference should be made to the fault finding instructions. whichever is more convenient. This completes the tests on the supervision module. the green LED comes on instantaneously and the pilot fail open circuit indicator operates after approximately 10 seconds. reset the pilot fail open circuit indicator. connect a multimeter across terminals 1 & 3 or 2 & 4. The green LED should illuminate. the green LED should come on. slowly turn the screwdriver anticlockwise until the green LED extinguishes. Confirm that removal of the ac supply operates the supervision supply indicator after a delay of approximately 10 seconds. reset the pilot fail short circuit indicator. followed by the pilot fail open circuit red LED approximately 10s later.which if depressed reduces the supervision band width inside which the pilots are considered healthy. continue to turn the screwdriver anticlockwise. If both these checks are satisfactory.
If any doubt exists manually move the disc. (We recommend using a burnishing tool . Refer to the safety requirements of the country of installation. • Inspect the relay for foreign matter and clean out if necessary. Check that the relay resets from the tripped position. available from ourselves. for safe handling of pilot wires. 4. • Measure and record the pilot voltage and current and the corresponding load current. The frequency of such tests cannot be laid down since much depends upon local conditions. The following tests are recommended for the MHOA. These can rise to a lethal high voltage relative to the ground potential under line fault conditions. Also it is normally advisable to check protective equipment after operation due to a fault. periodic inspection and test is recommended. • Check that all indicators operate satisfactorily. have been removed from the panel and then refitted. knives. under favourable conditions. Operation of the relay contacts should coincide with the respective LED indicator illuminating. place a short circuit across the pilot terminal of one relay. leaving the back up protection in service. noting the reduction in restraining torque compared to normal operating conditions. Inspect the contacts but do not disturb them unless badly pitted. which may be carried out with the feeder on load. files or abrasive materials be used). • With all trip links restored and all connections normal check that the trip circuit is healthy. to refurbish badly pitted contacts. • Remove the trip circuit isolating link of the translay relay. As a general guide. • Reverse the pilots and note that both relays close their contacts. • With the pilot connections restored to normal. MHOB and MHOC relays. Page 16 . If the load current is less than the three phase operating level of the relay there may be a small movement of the relay disc. or associated equipment. MAINTENANCE Suitable precautions should be taken before handling pilot wires. and an increase in pilot current. This check should preferably include tripping of the circuit breaker. especially the magnet gaps which should be cleaned with a feather. For the MRTP relay. This is necessary as under normal conditions protective gear is normally stable.1 Routine tests Routine tests should be carried out to confirm that the protection is still effective. the results of which should show a close relationship to the previously recorded commissioning test results. however. Routine tests need not be as comprehensive as commissioning tests unless any relays. annual tests should be adequate.Section 4. during testing the LED indicators should be checked for operation. Check also that the flag can be reset using the reset push button mounted in the relay cover. If the load current is less than the three phase operating level of the relay there may be a small movement of the relay disc. Periodic maintenance is not necessary. On no account should cleaning fluids. Check that operation is clean with no tendency to stick.
5% 13% 15% 90% 90% 45% 52% Table 1: Nominal relay settings Notes: 1. 3. HO4 and HOC4 respectively. For a four ended system these figures will have to be multiplied by 1. MHOB04 and MHOC04 relays are compatible with the previous equivalents. HOA4. Refer to the relay wiring diagram for the connections. the earth fault sensitivity can be altered.25.25 and N=6 on the MHOC relay. On the translay scheme an SJA relay would be used at one end with a cross pilot detection box at the other end. The fault settings will increase in proportion to any additional pilot resistance. Figure 11 shows how MRTP relays should be connected in a translay scheme. The settings in the above table for the MHOA are for a three ended system. Page 17 . By adjusting the effective neutral turns between N=2. The SJA was for use with protective schemes requiring a low impedance path for ac in the pilot circuit. The circuit diagrams in Figures 8. 4. The capacitors within the MRTP supervision relay have identical injection filters to those used in the SJA static pilot supervision relay. COMPATIBILITY The MHOA04. Now if an MHOB or MHOC protection scheme is in use and pilot supervision is required then MRTP relays would be necessary. Fault A–N B–N C–N A–B B–C C–A A–B–C MHOA (3 end) 13V 46% 56% 80% 180% 180% 90% 104% 26V 35% 45% 60% 140% 140% 70% 80% MHOB 22% 28% 40% 90% 90% 45% 52% MHOC N=2.Section 5. For the MHOA the alternative sensitivities are available by the use of different taps on the quadrature CT (13V or 26V). 9 and 10 show the pilot wire connections between these different relays. This relay contained a capacitor bank which was connected across the input terminals to the relay. The settings increase proportionally. 2. For 4kVrms 1minute isolation an MRTP01 will be used at the local end with an MRTP02 at the remote end.25 22% 28% 40% 90% 90% 45% 52% N=6 11. The settings for all three types of relay are quoted for a pilot of negligible resistance.
When two sets of current transformers are connected in parallel the allowable magnetisation current should be halved. the allowable magnetisation current may be increased. = Maximum secondary through fault current. = Reactance/resistance ratio (X/R) of the power system. The impedance of other phase connected devices. = Maximum secondary through phase fault current. 3. Where the minimum internal fault level is greater than this value. If the reactance/resistance ratio of the power system is not known assume that Q = 5. 2. must be added to the term in brackets when calculating the required voltage. Notes 1. The secondary magnetising current limit applies where the system minimum internal fault level is less than three times the current transformer rated primary current.05In at 10 + In(RCT + 2RL) In MHOC 04 Table 2: Current transformer requirements where In IF IFP IFE RL Q = Rated current. = Resistance per lead from current transformer to the relay. including both the source impedance and the impedance of the feeder to be protected.016In at 10 + In(RCT + 2RL) In 0. The kneepoint voltage of a CT is defined as that point of the magnetisation curve at which a 10% increase in voltage would cause a 50% increase in magnetisation current. Page 18 . = Maximum secondary through earth fault current. RCT = Resistance of the current transformer secondary winding. 4. 5.002In at 40 + In(RCT + 2RL) In MHOA 04 MHOB 04 IFQ 7 + R + 2R CT L 15 I2 IFPQ 7 + R + 2R CT L 15 I2 IFEQ 12 + R + 2R CT L 15 I2 0. such as instruments.Relay type Minimum secondary kneepoint voltage (V) 350 + IF(RCT + 2RL) In Secondary magnetising current limit (A) at the stated voltage (V) 0.
A P1 P2 S1 Primary injection test set S2 A Figure 1: Current transformer ratio test P1 S1 P2 S2 A V VARIAC (or equivalent) Figure 2: Current transformer magnetisation curve test Page 19 .
P2 P1 S2 S1 + Milliammeter DC Figure 3: Current transformer dc flick test Busbars A Feeder B C A A A A A B C N To pilots Primary injection test set Relay Figure 4a: Single phase injection Page 20 .
Busbars A Feeder B C Primary short circuit A A A A A B C N To pilots Primary injection test set Relay Figure 4b: Two phase injection Busbars A Feeder B C A B C N Primary injection test set Relay mA V To pilots Figure 5a: Relay setting test using primary injection – earth fault A–N Page 21 .
Busbars A Feeder B C Primary short circuit A B C N Primary injection test set Relay mA V To pilots Figure 5b: Relay setting test using primary injection – phase fault A–B Primary short circuit End 'A' A B C End 'B' A B C Primary injection test set N mA V A B C N Relay Relay Figure 6: Stability test using primary injection test set through A–B phase fault Page 22 .
End 'A' A B C End 'B' A B C N mA V A B C N Relay Relay Figure 7: Stability test using phase load current – through A–N earth fault Page 23 .
CT connections are typical only Note 4. If there is no possibility of an in feed from the remote end only a quad CT is required 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Module terminal block viewed from rear Figure 8: Type MHOA/HOA4 plain feeder protection . Earthing connections are typical only Note 3.A Protected zone P2 S2 S1 P1 TEE 'A' P2 TEE 'B' Protected zone A B C P1 S1 C B Phase rotation S2 See Note 3 1P2 1P1 1P1 1P2 23 24 25 27 28 MHOA 04 18 Pb Pb 18 17 R BK Pilot wire 1 Case earth 2 see Note 2 3 4 21 22 1P2 1P1 23 25 26 27 28 3P1 3P2 MHOA 04 18 17 Pb S1 S2 S3 Pa A B C Pb S1 S2 S3 Pa 3P1 3P2 A B C Pilot wire see Note 5 2P1 2P2 24 2P1 2P2 1P2 1P1 BK See Note 4 R 1 3 2 4 2P1 2P2 1 Case earth 3 see Note 2 2 21 4 22 2P2 2P1 26 Case earth 1 MHOA 04 17 2 3P2 3P1 Case earth see Note 2 2WR 21 2WW 22 23 2WBK 24 25 26 R 27 BK 28 3P1 3P2 Pa S1 S2 S3 3 4 5 6 Pa Quad CT 7 8 S3 S2 S1 Page 24 9 10 11 12 Pilot wire Note 1. Coil connections viewed from front Note 5. (a) (b) (c) CT shorting links make before (b) & (c) disconnect Short terminals break before (c) Long terminal Note 2.
CT connections are typical only Note 4.A Protected zone Phase rotation P2 P2 S2 S2 C Protected zone B P1 S1 A P1 B S1 C 1 3 2 4 3WR W R1 BK & 2WR 2WBK 3WBK 4 2 21 22 23 24 25 26 27 28 MHOB 04 18 S2 S2 18 R See Note 4 17 S1 S1 17 Pilot wires CT shorting links make before (b) & (c) disconnect Short terminals break before (c) Long terminal Note 2. Coil connections viewed from front BK BK R 3 Case earth See Note 2 1 Case earth Case earth See Note 2 R 21 22 23 24 25 26 27 28 MHOB 04 1 2 3 4 5 6 7 8 9 10 Page 25 11 12 13 14 See Note 3 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Note 1. (a) (b) Module terminal block viewed from rear (c) Figure 9: Type MHOB/HOB4 plain feeder protection . Earthing connections are typical only Note 3.
25 N=6 See Note 5 N=2. 27 28 (a) (b) Module terminal block viewed from rear (c) Figure 10: Type MHOC/HOC4 plain feeder protection . Note 4.25 N=6 See Note 5 19 20 21 22 23 24 25 26 Note 1. Earthing connections are typical only CT connections are typical only Coil connections viewed from front Make appropriate connection for required earth fault sensitivity (see fault settings table) BK BK 4 21 2 3 Case earth See Note 2 Case earth See Note 2 R 21 22 23 24 25 26 27 28 MHOC 04 1 Case earth 1 2 3 4 5 6 7 8 9 10 Page 26 11 12 13 14 See Note 3 15 16 17 18 N=2. Note 5.A Protected zone Phase rotation P2 S2 Protected zone C B P1 S1 A P1 P2 B S1 S2 C 1 3 2 4 3WR W BK & 2WR 2WW 2WBK 3WBK R1 22 23 24 25 26 27 28 MHOC 04 18 S2 S2 18 R R See Note 4 17 S1 S1 17 Pilot wires CT shorting links make before (b) & (c) disconnect Short terminals break before (c) Long terminal Note 2. Note 3.
(a) Module terminal block viewed from rear (b) (c) Figure 11: MRTP connections with a Translay scheme .S1 S2 Pilots 18 17 19 Case earth MRTP 02 OP Reset OP Reset OP DC power supply Reset RL6 1 RL7 1 V V V 20 18 S1 Translay Translay S2 17 V AC auxiliary supply 20 V Case earth 1 RL1 L1 2 19 V >I AC power supply RL2 L2 Supply fail 3 4 27 5 6 28 <I RL8 1 RL3 L3 Pilot S/C RL4–1 Output contacts change state for pilot fail Pilot O/C RL4 2 RL5–1 RL4–2 7 8 13 9 10 Vx Page 27 11 12 14 13 14 15 MRTP 01 +VE RL1 –1 Start –1 –1 RL2 RL3 RL1 –2 16 >I 17 18 19 20 21 22 RL2 –2 RL3 –2 RL5 2 RL5–2 Output contacts change state for supply fail 23 24 Case earth 25 26 t 27 CT shorting links make before (b) & (c) disconnect Short terminals break before (c) Long terminal 28 Note 1.
5% 13% 18% 90% 90% 45% 52% Page 29 . for safe handling of pilot wires. Translay protection relay Site: ____________________________________ Model No. C ______________________ N ___________________________ Relay settings (at minimum setting mark) Fault MHOA (3 end) 13V Nominal A-N B-N C-N A-B B-C C-A A-B-C 46% 56% 80% 180% 180% 90% 104% 26V MHOB N=2. These can rise to a lethal high voltage relative to the ground potential under line fault conditions. Refer to the safety requirements of the country of installation.: ____________________________ Diagram: ______________________________ Settings: _______________________________ _____________________________________________________________ _____________________________________________________________ A.Section 6.: _____________________________ Rating: _________________________________ Pilot Length: _____________________________ Current transformer tests CT ratio test CT magnetisation test CT polarity test Phasing out tests A ________________ B _________________ C __________________ Circuit: ________________________________ Serial No. B.25 MHOC N=6 Actual Actual Nominal Actual Nominal Actual Nominal Actual Nominal 35% 45% 60% 140% 140% 70% 80% 22% 28% 40% 90% 90% 45% 52% 22% 28% 40% 90% 90% 45% 52% 11. COMMISSIONING TEST RECORD Suitable precautions should be taken before handling pilot wires.
Monitor pilot fail contacts ____________________________________________ V ____________________________________________ V __________________________________________ mA _____________________________________________ _____________________________________________ Page 30 . Check supplies – AC V(n) – DC V(x) 2.Other checks: Flag operate/reset _______________________ Trip isolating switch _____________________ CT shorting switches _______________________ Contact operation ______________________ Relay stability tests Pilots normal Test A-N B-N C-N A-B B-C C-A A-B-C Pilot loop resistance ________________________ Ω Trip circuit test _____________________________ Pilot voltage Pilot current Relay restrains Pilot voltage Pilots crossed Pilot current Pilot operates MRTP ac pilot circuit supervision relay Site: ___________________________________ Model No. Set adjustable resistor 4. Monitor pilot current 3.:_______________________________ Rating AC V(n): _______________________ V Diagram: ________________________________ DC V(x) _______________________ V 1.: ____________________________ Circuit: __________________________________ Serial No.
Check supervision supply fail Remarks: _____________________________________________ ___________________________________ (green LED) _____________________________________ (red LED) ___________________________________ (green LED) _____________________________________ (red LED) ______________________________________ (redLED) Commissioning Engineer Date Customer Witness Date Page 31 .5. Check indications Pilot fail open circuit – instantaneous – 10s delay Pilot fail short circuit – instantaneous – 10s delay 6.
Which type of test was being used? 3. This form may also be used in the case of application queries. What did you expect to happen? continued overleaf ! . What parameters were in use at the time the fault occurred? AC Volts DC Volts AC current Frequency ___________________ ___________________ ___________________ ___________________ Main VT/Test set Battery/Power supply Main CT/Test set 2.REPAIR FORM Please complete this form and return it to AREVA T&D with the equipment to be repaired. Leonards Works Stafford ST17 4LX England For : After Sales Service Department Customer Ref: AREVA Contract Ref: Date: ___________________ ___________________ ___________________ Model No: Serial No: ___________________ ___________________ 1. List the relay settings being used Yes / No 5. AREVA T&D St. Were all the external components fitted where required? (Delete as appropriate) 4.
When did the fault occur? Instant Time delayed By how long? Yes / No Yes / No ___________________ Intermittent (Delete as appropriate) Yes / No 8.6. What did happen? 7. Any other remarks which may be useful: Signature Name (in capitals) Title Company name ! . What indications if any did the relay show? 9. Was there any visual damage? 10.
com T&D Worldwide Contact Centre online 24 hours a day: +44 (0) 1785 25 00 70 http://www.Publication: R8140B AREVA T&D's Automation & Information Systems Business www.areva-td.com/contactcentre/ .areva-td.
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