EPOXY MICA COUPLING CAPACITOR. Installation Manual. Epoxy Mica Coupling Capacitor - Installation Manual P/N: I1A-100

Transcription

1 EPOXY MICA COUPLING CAPACITOR Installation Manual Copyright VibroSystM Inc., 2013 Epoxy Mica Coupling Capacitor - Installation Manual P/N: I1A-100

2 Epoxy Mica Coupling Capacitor - Installation Manual

3 INSTALLATION OF EPOXY MICA COUPLING CAPACITORS JUNE 2010 Dynamic Ratings, Inc Electrical Diagnostic Innovations Aspen Lane N # Brooklyn Park, MN

4 TABLE OF CONTENTS 1.0 Introduction Main Technical data for DYNMAIC RATINGS couplers Capacitor Installation Locations Primary connections and grounding Secondary connections Recommended tools and materials Installing the coupler High Voltage connections: Ground connections: Detailed installation instructions Preparation of Coax Cable Mounting of the Capacitor Installation using insulating boot Taping the Connection instead of using the boot Couplers on hydro-generators Couplers on large generators Coupler connections in bus ducts Coupler connection in transformers Appendix A APPENDIX B - Sample Installtion Pictures Smarter Solutions For Today and Tomorrow

5 1.0 INTRODUCTION An epoxy-mica coupling capacitor (coupler) is a device for sensitive detection of the partial discharges in the electrical insulation of medium voltage AC apparatus, such as switchgears, motors, generators, transformers and other auxiliary medium voltage equipment. Refer to the nameplate for the rating of the coupler and compare the rating with the equipment voltage class before attempting installation! TO PERFORM INSTALLATION OF THE PRODUCT DESCRIBED IN THIS INSTRUCTION MANUAL, THE SUBJECT ELECTRICAL EQUIPMENT HAS TO BE DEENERGIZED AND SUITABLY SAFEGUARDED. ALL WORK HAS TO BE PERFORMED BY PERSONELL WHO ARE QUALIFIED TO WORK ON HIGH-VOLTAGE ELECTRICAL EQUIPMENT WHILE STRICTLY ADHERING TO THE LOCAL SAFETY REGULATIONS. DISCLAIMER AND INDEMNIFICATION Any person, firm or individual who installs or arranges for any other person, firm or individual, other than DYNMAIC RATINGS., to install the PDA capacitive coupler system, shall assume all risks and damages relating to or arising out of such installation. DYNMAIC RATINGS. hereby disclaims any responsibility or obligation whatsoever for or in connection with the installation of the PDA capacitive coupler system. The purchaser shall indemnify and save DYNMAIC RATINGS. harmless against any and all liabilities, losses, damages, claims, suits and expenses of whatsoever kind and nature imposed or asserted against DYNMAIC RATINGS. relating to or arising out of the installation of the PDA capacitive coupler system. COPYRIGHT NOTICE 3 Smarter Solutions For Today and Tomorrow

6 The information contained in this document is confidential and the property of DYNMAIC RATINGS. Photocopied or electronic reproduction in whole or in part without the written consent of DYNMAIC RATINGS. is strictly prohibited. This document shall not be sold, transferred or otherwise made available to any third party. Failure to comply with the copyright notice will result in penalties as prescribed by law. 4 Smarter Solutions For Today and Tomorrow

7 2.0 MAIN TECHNICAL DATA FOR DYNMAIC RATINGS COUPLERS Dynamic Ratings supplies three voltage levels of epoxy mica coupling capacitors. Common Parameters Operating Temperature - 40 o C to 150 o C. Construction Epoxy Mica Mounting Vertical or Horizontal Diameter, inches/cm 3.5/9.1 Sensitivity, pc < 1 Capacitance, pf pf Frequency Range 0.5 MHz to 500 MHz Voltage Rating (kv) AC Hipot (kv) BIL (kv) Height (mm / Inch) with mounting base / / / Additional Specifications Mass (kg) Meets ANSI/IEEE C ) Electrical Tracking Resistance Easily withstands 30 kv for 1500 hours (IEEE 1043) Voltage Endurance Test Dielectric Strength: 775 V/mil Insulating boots are provided to reduce installation time since no taping is required High Temperature Silicone jumper cable is provided for connection to the high voltage. Resists cracking and is extremely flexible compared to standard jumper cable 5 Smarter Solutions For Today and Tomorrow

8 Unlike many other capacitor installations, the Dynamic Ratings capacitor is grounded at the point of installation and not at an external termination box. The Dynamic Ratings protection is located at the capacitor. This provides a couple of key advantages. A. Additional Safety to operating and testing personnel. If the protection located in the termination box fails, high voltage can appear at the test terminals that could produce a life threatening shock. B. Provides for better signal propagation for better measurements. There is no concern in looping cables or making sure they lie on a grounded surface. 3.0 CAPACITOR INSTALLATION LOCATIONS Since there are no standards in designs of motors and generators, the location of mounting the capacitors always varies. Each installation must be evaluated to determine the best location. In all instances, the capacitor is connected from each phase to ground. In addition, Radio frequency current transformers (RFCTs) for motors and cable connected generators or a set of additional capacitors on large generators can be installed to determine pulse direction. Also, Dynamic Ratings uses the existing RTDs in the windings as PD sensors. Refer to our Application Guides and other documentation for additional information. It is desirable to locate the capacitor as close as possible to the machine windings in the machine termination box and to keep the cable connecting the capacitor to the HV bus as short as possible. Additional length on the cable can greatly attenuate the PD signals and lower sensitivity. Typically capacitors installed at the line terminals only cover approximately 15% of the winding closest to the terminations. Any PD occurring deeper in the winding will not be detected. This is why Dynamic Ratings uses the RTDs as additional sensing point. Refer to our web site ( or contact Dynamic Ratings for additional information on this topic. The following illustrations show sensor configurations and preferred methods of capacitor installation. IN ALL CASES, USE COMMON SENSE AND BE PRACTICAL. DO NOT COMPLETELY REDO A MOTOR TERMINATION BOX JUST TO COMPLY WITH THE RECOMMENDATIONS. 6 Smarter Solutions For Today and Tomorrow

9 Preferred method Alternate method 7 Smarter Solutions For Today and Tomorrow

10 4. PRIMARY CONNECTIONS AND GROUNDING To ensure minimum inductance, all primary connections should be as short as possible. The coupler can be installed in the following ways: A) Directly attached to metal cabinet floors, walls or ceilings. When using this option you need to drill holes or cut into the metal surface or install a spacer, so the outgoing coaxial cable from the secondary terminals of the coupler on is grounded and provide sufficient space for the coax wire. B) Attached with the custom-made ground bars or brackets at least 1 wide, or strong enough to support the capacitor and connections. The bus bars and brackets should be as short as possible and directly grounded on both ends to the frame. C) If ground bonding of the mounting surface is questionable, use additional ground wire to the ground bus or grounded frame. Always check the integrity of the coupler ground before energizing. D) The connections to the primary (high voltage) circuits should be no longer than 2-3 and made of a bus bar with a cross-section not less than 1 x 0.1 or of A non-shielded high voltage bare or insulated conductor of a size not less than #4 AWG should be used. Excessive length of cables should be trimmed to minimum. E) The conductors must be routed to ensure proper clearances between the grounded and live parts, as required by appropriate ANSI standards covering the equipment enclosures in which the coupler is being installed. As an example of a rule of thumb for a system rated 15 kv, the ground clearances for the bare conductors should be at least 6 and the clearances between the live parts of different phases at least 8. Use of appropriate barriers or insulated conductors may allow significant reduction of such clearances but requires dielectric testing of the equipment before returning to operation. F) The connections must be free of partial discharges and corona. Avoid sharp edges; if connections should be taped, use proper semi-conductive and grading tapes to avoid local concentration of electric stresses that can cause partial discharges. G) Coupler connections to surge capacitors or surge arresters terminals should be avoided if possible. Such installation will significantly decrease the sensor sensitivity because these capacitors and arresters have essential stray capacitance, thus reducing the impulse current flowing inside the sensor. 8 Smarter Solutions For Today and Tomorrow

11 5. SECONDARY CONNECTIONS The coupler design requires sufficient free space around the secondary signal connections made to the two inserts at the bottom of coupler. For this reason, the secondary terminals are located to one side of a 3/8 deep recess to allow easier connection to the instrumentation using standard 50-Ohm coaxial cable terminated with crimped-on ring terminals. The signal conductor is terminated by red ring terminal and the shield by blue ring terminal. A standard length cable (25 ) is included with each coupler as well as connecting hardware and tie wraps. If the sensors are to be installed on a flat solid surface, an opening has to be provided in the surface to accommodate the secondary cable. It is recommended that a suitable rubber bushing or grommet be used to protect the cable from sharp edges of the opening. As an alternative, a suitable recess in the grounded surface, or a suitable mounting bracket can be provided to allow the access to the secondary connections. Note: Avoid application of excessive torque or tension to the coaxial cable connections; secure the cable with cable ties. 9 Smarter Solutions For Today and Tomorrow

12 6. RECOMMENDED TOOLS AND MATERIALS Mounting bolts, nuts, washers and drill bits to mount the capacitor base to a grounded metal structure. High voltage conductor (bare or insulated) for coupler connection to HV Circuits. Minimum conductor size of #4 is recommended. If the installation kit including 15 kv cables was additionally ordered it would be included into the shipment. The aluminum brackets included in the shipment: Grounding bars (if necessary) copper bars with cross-section not less than 1 x ¼. Coaxial cables (included in the shipment): either of the standard 25 length or in spools of 1000 with additional payment for the length in excess of the standard 25 feet per sensor, according to the Customer order. 7. INSTALLING THE COUPLER HIGH VOLTAGE CONNECTIONS: o o o o By direct connection to HV bus bars (if the bus is covered with an insulating Sleeve, or a coating, make sure that the bolt has a good electrical contact to the conductor); By connection to HV bus or termination with an insulated conductor (maximum 4 length, but make it as short as possible); By connection to HV bus or termination with a bare stranded or solid conductor or bus bar. 10 Smarter Solutions For Today and Tomorrow

13 GROUND CONNECTIONS: By direct mounting on grounded surface; By mounting of a group of sensors on a single grounding bar anchored to the metal cabinet surface with an additional ground wire to assure good ground connection; By mounting of an coupler on a its bracket anchored to the metal cabinet Surface, if necessary- with an additional ground wire to assure good ground connection. Always check electrical connections to HV circuits and ground before Energizing after capacitor installation. Dielectric tests after installation are preferred. 8. DETAILED INSTALLATION INSTRUCTIONS 8.1 PREPARATION OF COAX CABLE A. Place one piece of heat shrink insulation over the coax wire B. Strip approximately 1 inch (25 mm) of outer insulation from the wire C. De-braid the shield wire and twist tightly D. Remove about ¼ inch or 6 mm of insulation from the center conductor E. Crimp the Red ring terminal on the exposed central conductor F. Crimp the Blue ring terminal on the twisted shield wire G. Slip the Heat shrink tubing over the connection as tight as possible and heat to hold in place. H. Mount the capacitor on to the bracket using two 3/8 inch bolts and lock washers (provided) I. Make sure the shield wire does not ground to the bracket. J. To ensure proper connection, you should measure 1,500 3,000 ohms between the shield and center conductor from the other end of the cable. 11 Smarter Solutions For Today and Tomorrow

14 8.2. MOUNTING OF THE CAPACITOR A. The coupler mounting base, shown here is to be attached to a convenient position within the termination box, generator or bus duct, using two M8 or 3/8 inch or similar bolts. Drill holes as necessary. Before mounting the base, mount the capacitor to the base and secure the green ground wire to the base using the 6-32 screw and nut provided. Ensure all bolts are secured against vibration. Hardware is not provided for installation of the base. B. Once the capacitor is mounted, determine what length of the high voltage jumper cable you require. Tightly attach the cable to the top of the capacitor using one 3/8 bolt and lock washer (Provided). If it is more convenient for a short connection, copper strips can be used instead of high voltage cable. This strip should be cut to length and drilled appropriately. Ensure that any expected thermal expansion is allowed for in connection lengths. 12 Smarter Solutions For Today and Tomorrow

15 8.3. INSTALLATION USING INSULATING BOOT In place of tape, Dynamic Ratings provides insulating boots that go over the connection. This is suitable more most applications for motors and switchgear. If the temperature is going to exceed 90 o C then taping is recommended. Slip the boot over the high voltage cable and the top of the capacitor. Fasten the boot closes with plastic screws or tie wraps. Completed Capacitor 13 Smarter Solutions For Today and Tomorrow

16 8.4 TAPING THE CONNECTION INSTEAD OF USING THE BOOT. C. To insulate the cable connection, the following instructions should be followed. In some rare situations it may not be required to insulate the HV connection, but this should only be decided after a full study by an engineer for each situation. For example, situations where insulation is required include: The coupler is not well clear of other potentials (inc. earth) and there is not full HV clearance at the top, The coupler top is not absolutely assured that there is no risk of other conductors approaching (inc during a fault). The HV system is insulated in the vicinity of the coupler installation, such as inside a machine, or has insulated bus bars. If there is any policy or preference to insulate HV in the intended mounting position. If there is any vibration risk that the coupler connection may loosen, which the insulation will secure. D. Smooth the connection point using putty tape (Rotunda 2571), Stretch the tape to 50% elongation and apply under tension pressing down firmly around the bolt/lug. Rotunda 2571 E. Insulate the connection using 4 half-lapped layers of PIB tape (Rotunda 2501). Stretch the tape to at least 2/3 of its original width. Tapes should cover the top AND the first 19 mm (3/4 ) from the top of the Coupler. 14 Smarter Solutions For Today and Tomorrow

17 PIB tape application F. Cover the PIB tapes with two layers of silicone tape. (All layers should half-overlap) Silicone tape application 15 Smarter Solutions For Today and Tomorrow

18 G. Two layers of fiberglass tape should be applied if tape insulated part is to be coated with air-drying varnish (for example, Synthite AC-43, manufactured by John C. Dolph company) Fiberglass tape application 16 Smarter Solutions For Today and Tomorrow

19 9. COUPLERS ON HYDRO-GENERATORS The easiest way is to connect coupler to the ring bus of the generator. For larger generators two sets of coupler is recommended for better coverage. Each set will service a half of winding. Coupler should be connected to the ring bus close to the leads of opposite parallels. 10. COUPLERS ON LARGE GENERATORS On large generators coupler installation will highly depend on the design of the output lead chamber and the adjacent bus sections. The best way is to install coupler sensors in the lead bushing chamber. If it is not possible, coupler could be installed in the beginning of the adjacent bus section. Additional sets could be installed in the bus duct for noise rejection and bus monitoring purpose. 11. COUPLER CONNECTIONS IN BUS DUCTS Two sets of three coupler devices each should be installed at both ends of a bus duct for PD detection. The two sets are necessary for accurate identification of PD site location along a bus utilizing a time-of-arrival method. 12. COUPLER CONNECTION IN TRANSFORMERS Three coupler, one per phase, are typically required at the medium voltage side of a transformer. If the connection is a bus duct, one set of coupler can serve for detection of PD in both the transformer and the bus duct. 17 Smarter Solutions For Today and Tomorrow

20 APPENDIX A For proper installation of the PD system, the coaxial cables running from the couplers to the termination box have to be placed inside a conduit. Check the local regulations for the conduit material to be used. During the machine operation, there is very strong electrical field present in the vicinity of the isophase bus. Since the conduit is always installed close to isophase bus it is highly important that conduit is laid out in such a way to prevent circulating currents from occurring. In order for PD system to be properly installed, termination box and conduit itself have to be grounded. This has to be done on one and only one place preferably close to the termination box itself. Make sure that coaxial cables conduit is insulated from any other conducting surface (i.e. conduit support holders, I beams, bus duct enclosure, etc.). A rubber hose or few layers of insulation tape can be used to insulate conduit from conduit holders. To insulate conduit from bus duct enclosure, short runs of plastic conduit or plastic bushings can be used. Dynamic Ratings, Inc Electrical Diagnostic Innovations Aspen Lane N # Brooklyn Park, MN 55428

21 APPENDIX B - SAMPLE INSTALLTION PICTURES 19 Experts in Diagnostic Monitoring Technologies