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Ferrite kit Accessory for timing of GIS circuit breakers using TM1800 with DualGround™ User’s Manual WWW.MEGGER.COM ZP-CG04E Ferrite kit Accessory for timing of GIS circuit breakers using TM1800 with DualGround™ User’s Manual NOTICE OF COPYRIGHT & PROPRIETARY RIGHTS © 2009, Megger Sweden AB. All rights reserved. The contents of this manual are the property of Megger Sweden AB. No part of this work may be reproduced or transmitted in any form or by any means, except as permitted in written license agreement with Megger Sweden AB. Megger Sweden AB has made every reasonable attempt to ensure the completeness and accuracy of this document. However, the information contained in this manual is subject to change without notice, and does not represent a commitment on the part of Megger Sweden AB. Any attached hardware schematics and technical descriptions, or software listings that disclose source code, are for informational purposes only. Reproduction in whole or in part to create working hardware or software for other than Megger Sweden AB products is strictly prohibited, except as permitted by written license agreement with Megger Sweden AB. TRADEMARK NOTICES Megger® and Programma® are trademarks registered in the U.S. and other countries. All other brand and product names mentioned in this document are trademarks or registered trademarks of their respective companies. Megger Sweden AB is certified according to ISO 9001 and 14001. Megger Sweden AB Eldarvägen 4 Box 2970 SE-187 29 TÄBY Sweden ZP-CG04E T +46 8 510 195 00 F +46 8 510 195 95 [email protected] www.megger.com Ferrite kit 3 Contents 1 Safety ____________________________________ 6 5 Application examples ___________________________________ 16 1.1 General................................................................ 6 Without and with transformer disconnector............. 16 1.2 Safety instructions................................................ 6 Insulated ground switch only available on the bus bar....................................................... 16 2 Introduction ____________________________________ 8 Application area......................................................... 8 Principle of a ferrite.................................................... 8 When is a ferrite required................................... 8 2 Kit description ___________________________________ 10 Insulating ground switches missing.......................... 17 Cable grounded in another substation..................... 17 Generator circuit breaker set-up............................... 18 6 Specifications ___________________________________ 20 Index....................................................................... 22 Ferrite kit parts......................................................... 10 3 Basics ___________________________________ 12 Prerequisites............................................................ 12 Insulated ground switch.................................... 12 Shape of shunts and spacing between shunts and casing............................................................... 12 Shunts need to have insulation washers............ 12 Flexible cables with ferrites attached................. 12 Alternative paths for the ground current........... 13 Maneuver shafts............................................... 13 Shielded cables................................................. 13 All other ground connections............................ 13 Too many parallel ground connections.............. 13 Too long measurement loop............................. 13 4 Mounting / Set-up ___________________________________ 14 Mounting combinations........................................... 14 Attaching the hook and loop fastener ............. 14 How to connect the DCM-cables............................. 14 Set mode for DCM and tune the system.................. 15 How to enter the GIS mode.............................. 15 To switch back to normal mode........................ 15 Tuning.............................................................. 15 4 Ferrite kit ZP-CG04E ZP-CG04E Ferrite kit 5 1 Safety 1 Safety 1.1 General 1.2 Safety instructions Sharp edges Important Read and comply with the following instructions. Always comply with local safety regulations. 6 Ferrite kit The ferrites have sharp edges and have to be handled by care to avoid personal injury. Fragile The ferrites are very fragile and need to be handled with care. For example dropping the ferrite to the ground will most probably cause that it will crack. Due to this there is no warranty on damaged ferrites. ZP-CG04E 1 Safety ZP-CG04E Ferrite kit 7 2 Introduction 2 Introduction Application area Principle of a ferrite Time measurement, using TM1800 with Dynamic Capacitive Measurement (DCM), on Gas Insulated Switchgear (GIS) Circuit Breakers (CB) grounded on both sides using ground switches / earth switches. One property of the ferrite is that it increases the impedance of a conductor it surrounds. Since the DCM technology uses high frequency AC current as test current we can take advantage of this property to increase ground loop impedance. When is a ferrite required Ferrites are needed when the ground loop has low impedance compared to the circuit breaker loop. On Air Insulated Switchgear (AIS) ferrites are normally not required due to that the ground loop is considerably longer than the circuit breaker loop. On GIS breakers, though, the ground loop is usually about the same length as the circuit breaker loop and therefore ferrites are required to increase the impedance in the ground loop. 8 Ferrite kit ZP-CG04E 2 Introduction Test leads Test leads Circuit breaker loop Circuit breaker loop Ground loop Ground loop CB CB To DCM module Insulation Insulation Ferrite Ferrite To ToDCM DCMmodule module Test leads Circuit breaker loop Ground loop Test leads module To DCM To DCM module Circuit breaker loop Ground loop To DCM module To DCM module Relation between ground loop and CB loop on GIS, open air and dead tank circuit breaker. ZP-CG04E Ferrite kit 9 2 Kit description 2 Kit description Ferrite kit parts Designation Pcs Art.No. Transport case 1 GD-00440 C-shape ferrite 7 XB-40010 I-shape ferrite 4 XB-40020 Round ferrite 4 30-67090 Hook and loop fastener 4 09-10140 User’s Manual 1 ZP-CG04E 10 Ferrite kit ZP-CG04E 2 Kit description ZP-CG04E Ferrite kit 11 3 Basics 3 Basics Prerequisites Flexible cables with ferrites attached Insulated ground switch If the dimensions of the shunt and/or the spacing don’t allow attaching a ferrite, the shunt can be replaced by a flexible cable on which a round shaped ferrite can be attached. At least one of the ground switches need to be of insulated type, i.e. there must be a part, connected to the inner conducting part (through the closed ground switch), that is possible to disconnect electrically by detachable jumpers or shunts. CB Conducting part Important Before replacing the shunt with a cable the following points must be obeyed: Always comply with local safety regulations. Insulation Ferrite Detachable shunt Insulated ground switch with shunt and ferrite attached Shape of shunts and spacing between shunts and casing The shunts have to be shaped in a way that it is possible to attach a ferrite around it. Likewise, there must be enough space between the shunt and the casing of the ground switch to fit a ferrite. Shunts need to have insulation washers The circuit breaker must be closed and grounded on both sides. The shunt replacement (cable) must be mounted before the shunt is removed. The cable must have the same as, or better conducting capability than, the shunt. The shunt replacement must be approved by the manufacturer of the GIS circuit breaker. Examples of flexible cables with ferrites attached The bolts holding the shunts have to be equipped with insulation washers. If not, attaching ferrites around the shunts will have no effect since the current is conducted through the bolts. Insulation washer Ferrite Grounding shunt Insulation washer No insulation washer Current path with and without insulation washer 12 Ferrite kit ZP-CG04E 3 Basics All other ground connections In some installations the isolated part of the ground switch is not only grounded through the shunts but also has a separate grounding bar. In such case ferrites need to be applied on the grounding bar. Too many parallel ground connections A parallel shunt / ground connection decreases the impedance by half although ferrites are applied on both paths. If there are too many parallel shunts/connections to ground the resulting impedance might be too low for DCM to sense a difference between closed an open circuit breaker. Where the limit of number of parallel paths is cannot be stated generally, but has to be tested out from installation to installation. On the contrary, putting ferrites in series on the same shunt / ground connection increase the impedance. So this might be a solution when there are too many parallel paths to ground. Too long measurement loop Alternative paths for the ground current To achieve desired functionality ferrites must be applied on all shunts and/or devices that interconnect the insulated part of the ground switch to ground, for example: Maneuver shafts The DCM measurement circuit is optimized for best amplitude response when connected to GIS circuit breakers having reasonable distance between ground switches, say 10 m (33’), however, distances up to 20 m (66’) might be managed. Note This is not guaranteed functionality, and it has to be tested out from case to case. Long distances between groundings can be found in out-door GIS installations or if the bus bar is equipped with an insulated ground switch. The ground switch might be operated by a maneuver shaft that transfers the power from the operating mechanism to the switch, in case the operating mechanism is externally located. If this maneuver shaft is made of a conducting material you need to apply a ferrite around it. If the same maneuver shaft operates all three phases, ferrites need to be applied between the phases to separate them from each other. Shielded cables If there is a signal cable going to the ground switch it is most likely of shielded type and then it is necessary to apply a ferrite around the cable. ZP-CG04E Ferrite kit 13 4 Mounting / Set-up 4 Mounting / Set-up Mounting combinations Important Always comply with local safety regulations. There are three mounting possibilities with the ferrite kit: A] Round ferrite to attach on cables or maneuver shafts B] C-shape combined with I-shape when the spacing between shunt and casing is small C] Two C-shapes when the shunt is thicker than 12 mm (½ ”) Combination B and C How to connect the DCMcables The access point for one of the test lead clamps is on the isolated part of the ground switch. However, choosing the second access point might not be equally obvious. The principles for selecting measurement lead access points are: ▪▪The longer ground loop the better ▪▪The shorter loop through the circuit breaker the better So, if there is a choice of access points the most suitable ones according to the above rules should be selected. In most cases though it is sufficient to connect the test clamps on each side of the ferrite. Attaching the hook and loop fastener If the space between shunt and casing is small it might be wise to first apply the hook and loop fastener to the I-shaped ferrite before it is entered behind the shunt, and then apply the C-shaped ferrite. Note To obtain full effect of the ferrites they must be fastened tight together, without any air gap between the contact surfaces. 14 Ferrite kit ZP-CG04E 4 Mounting / Set-up Set mode for DCM and tune the system The TM1800 DCM module has two modes – Normal mode and GIS mode. The difference between the two modes is that the GIS mode is more sensitive. After starting TM1800 the DCM mode is always reset to normal mode. 2] Press the TUNE button shortly. The tuning is performed automatically channel by channel and its corresponding LED flashes. Tuning will take about half a minute and when finished all channel LEDs, with cables connected, will be lit. 3] Proceed as a normal time measurement. ▪▪The normal mode shall be used on open air circuit breakers. ▪▪The GIS mode shall be used for GIS circuit breakers but it can also be used for open air circuit breakers having one interrupter per phase. How to enter the GIS mode 1] Keep the TUNE button pressed down for more than five seconds. The DCM module will confirm the mode change by flashing all LEDs simultaneously. Once the TUNE button is released the tuning will start in opposite channel order, i.e. beginning with channel C2 and ending with channel A1. The reversed tuning order is an indication of that the DCM module is in GIS mode. To switch back to normal mode 1] Keep the TUNE button pressed down for more than five seconds. The DCM will confirm the mode change by flashing all LEDs simultaneously. Once the TUNE button is released the tuning will start beginning with channel A1 and ending with channel C2. Note If tuning is not successful (LEDs off after completed tuning) it could hint that the impedance of the circuit is too low. To fix this problem the DCM cables between the small box and the clamps can be spread from each other. If you move the position of a DCM cable’s high frequency part (between small box and circuit breaker) you need to re-tune the system. The same applies if ferrites are moved/ added/removed. Tuning Once all ferrites are attached the system need to be tuned. This must be done when the circuit breaker is in closed position. 1] Check that the circuit breaker is in closed position. ZP-CG04E Ferrite kit 15 5 Application examples 5 Application examples Without and with transformer disconnector Insulated ground switch only available on the bus bar Both are possible with DCM. In this example the B bus bar need to be taken out of A service. B A B A A B B CB CB CB CB GIS GIS GIS GIS A B Measurement lead access points are shown with red arrows. CB GIS Measurement lead access points are shown with red arrows. 16 Ferrite kit ZP-CG04E 5 Application examples Insulating ground switches missing Cable grounded in another substation Access points outside GIS e.g. on transformer or line. In these examples ferrites might be needed on the transformer and line grounding. Important Before you connect the test leads you must confirm that there is less than 0.7 A volts potential difference between the B access points when the circuit breaker is open. A B No ferrites needed in this example. Access point to conducting part of cable can, on certain GIS designs, CB be found at the bushing where the cable connects to the GIS. On some designs an insulation cone can be removed to get access to the conducting part. CB A B GIS GIS CB Optional ferrite Line Optional ferrite A A B B GIS Cable grounded in another substation CB Measurement lead access points are shown with red arrows. GIS Optional ferrite Line Measurement lead access points are shown with red arrows. ZP-CG04E Ferrite kit 17 5 Application examples Generator circuit breaker set-up No ferrites needed in this example. The generator’s winding gives sufficient impedance in the ground loop. G GCB Measurement lead access points are shown with red arrows. 18 Ferrite kit ZP-CG04E 5 Application examples ZP-CG04E Ferrite kit 19 6 Specifications 6 Specifications Specifications Dimensions A B C D E F F C-shape ferrite Note: Measures does not include hook and loop A E 101.5 mm (4") 20.5 mm (0.81") 37.5 mm (1.48") 13.5 mm (0.53") 85.5 mm (3.37") 8 mm (0.31") fastener D C B I-shape ferrite A B C 102 mm (4.02") 7.5 mm (0.3") 37.5 mm (1.48") Note: Measures does not include hook and loop A fastener B C A B C 55.5 mm (2.18") 43 mm (1.69") 26 mm (1.02") Max. cable diam. 25.4 mm (1") C Round ferrite A Hook and loop fastener B 26 X 290 mm (1.02 X 11.4") Transport case 390 x 310 100 (15.4" x 12.2" x 3.9") Weight 20 4.5 kg (9.9 lbs) total kit including transport case Ferrite kit ZP-CG04E 6 Specifications ZP-CG04E Ferrite kit 21 Index Index A Application examples..................................... 16 C Connect the DCM-cables............................... 14 C-shape ferrite................................................ 10 F Flexible cables................................................ 12 G GIS mode....................................................... 15 Ground current............................................... 13 Ground switch................................................ 12 H Hook and loop fastener...........................10, 14 I Insulated ground switch.................................. 12 Insulation washers.......................................... 12 I-shape ferrite................................................. 10 M Maneuver shafts............................................. 13 Measurement loop.......................................... 13 Mounting......................................................... 14 N Normal mode.................................................. 15 P Parallel ground connections........................... 13 Principle of a ferrite.......................................... 8 R Re-tune........................................................... 15 Round ferrite................................................... 10 S Set mode for DCM.......................................... 15 Shielded cables.............................................. 13 Shunts............................................................ 12 T Tune the system............................................. 15 22 Ferrite kit ZP-CG04E Your “One Stop” Source for all your electrical test equipment needs ▪▪ Battery Test Equipment ▪▪ Cable Fault Locating Equipment ▪▪ Circuit Breaker Test Equipment ▪▪ Data Communications Test Equipment ▪▪ Fiber Optic Test Equipment ▪▪ Ground Resistance Test Equipment ▪▪ Insulation Power Factor (C&DF) Test Equipment ▪▪ Insulation Resistance Test Equipment ▪▪ Line Testing Equipment ▪▪ Low Resistance Ohmmeters ▪▪ Motor & Phase Rotation Test Equipment ▪▪ Multimeters ▪▪ Oil Test Equipment ▪▪ Portable Appliance & Tool Testers ▪▪ Power Quality Instruments ▪▪ Recloser Test Equipment Megger is a world leading manufacturer and supplier of test and measurement instruments used within the electric power, building wiring and telecommunication industries. ▪▪ Relay Test Equipment ▪▪ T1 Network Test Equipment ▪▪ Tachometers & Speed Measuring Instruments With research, engineering and manufacturing facilities in the USA, UK and Sweden, combined with sales and technical support in most countries, Megger is uniquely placed to meet the needs of its customers worldwide. ▪▪ TDR Test Equipment ▪▪ Transformer Test Equipment ▪▪ Transmission Impairment Test Equipment For more information about Megger and its diversified line of test and measurement instruments: www.megger.com ▪▪ Watthour Meter Test Equipment ▪▪ STATES® Terminal Blocks & Test Switches ▪▪ Professional Hands-On Technical and Megger is certified according to ISO 9001 and 14001. ▪▪ Safety Training Programs Megger is a registered trademark UK Archcliffe Road, Dover CT17 9EN England T +44 (0) 1304 502101 F +44 (0) 1304 207342 E [email protected] Other Technical Sales Offices Dallas USA Norristown USA Toronto CANADA Trappes FRANCE Oberursel GERMANY Johannesburg SOUTH AFRICA Kingdom of BAHRAIN Mumbai INDIA Chonburi THAILAND Sydney AUSTRALIA WWW.MEGGER.COM SWEDEN Megger Sweden AB Eldarvägen 4 Box 2970 SE-187 29 TÄBY T +46 8 510 195 00 F +46 8 510 195 95 E [email protected] Subject to change without notice. Printed matter No. ZP-CG04E Doc. CG1842BE 2009
