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DELTA 4000

ZM-AH02E

Summary of Contents for DELTA 4000

Page 1: ...WWW MEGGER COM Reference Manual Applications Guide DELTA4000 12 kV Insulation Diagnostic System ZM AH02E Advanced Test Equipment Rentals www atecorp com 800 404 ATEC 2832 Established 1981...

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Page 3: ...f 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 schematic...

Page 4: ...nsformer excitation current tests 19 Shunt reactors 21 Potential transformers 21 Current transformers 21 Voltage regulators 21 Dry type transformers 22 Bushings 22 Introduction 22 Definitions 22 Bushi...

Page 5: ...ZM AH02E DELTA4000 5...

Page 6: ...HV terminal and the current is measured at the LV terminal Voltage and current are accurately measured in amplitude and phase and CHL capacitance dissipation factor power loss etc are calculated and d...

Page 7: ...phase angle q q 90 It is more convenient to use the dielectric loss angle d where d 90 q For low power factor insulation Ic and I are substantially of the same mag nitude since the loss component Ir...

Page 8: ...internal measure ment connections UST Ungrounded specimen testing Test mode Measure Ground Guard UST R Red Blue UST B Blue Red UST RB Red and Blue GST Grounded specimen testing Test mode Measure Grou...

Page 9: ...ZM AH02E DELTA4000 9 1 Introduction...

Page 10: ...lar types of insulation used Changes in the normal capacitance of an insulation material indicate such abnormal conditions as the presence of a moisture layer short circuits or open circuits in the ca...

Page 11: ...factor values Typical power factor values 20 C New Old Warning alert limit Power trans formers oil insulated 0 2 0 4 0 3 0 5 0 5 Bushings 0 2 0 3 0 3 0 5 0 5 IEEE 62 1995 states The power factors reco...

Page 12: ...ielectric loss which in turn causes a further rise in temperature etc thermal runaway It is important to determine the dissipation factor tempera ture characteristics of the insulation under test Othe...

Page 13: ...may be contaminated enough to cause a signifi cant error Surfaces of potheads bushings and insulators should be clean and dry when making a measurement It should be noted that a straight line plot of...

Page 14: ...to the test specimen Other sources for interference may be corona discharges espe cially at high humidity and is some cases DC fluctuations in the grounding system Trouble from magnetic fields encoun...

Page 15: ...ZM AH02E DELTA4000 15 2 Interpretation of measurements...

Page 16: ...its from each other and it can increase or decrease the apparent value of a capacitor an inductor or a resistor Furthermore the transformer enables us to transmit electrical energy over great distance...

Page 17: ...applying any voltage on the transformer make sure that all bushing current transformers are shorted out 4 Never perform electrical tests of any kind on a unit under vacuum Flashovers can occur at volt...

Page 18: ...additional tests of the tertiary winding In some cases transformers are constructed so that the inter windings are shielded by a grounded electrostatic shield or a concentric winding arrangement This...

Page 19: ...e Subscripts are test num bers H High voltage winding L Low voltage winding T Tertiary winding G Ground Autotransformers In the design of an autotransformer the secondary winding is actually part of t...

Page 20: ...nd on wye connected transformers Also note that in many cases the maximum applied voltage is limited by the maximum current output Test voltage must always be the same as prior tests if any comparison...

Page 21: ...tial transformer is securely grounded to a system ground before testing begins this also includes testing of spare transformers Test procedure Ensure the test set is securely grounded 1 Record all tes...

Page 22: ...handle high electrical stress they could be subjected to mechanical stresses affiliated with connectors and bus support as well Although a bushing may be thought of as somewhat of a simple device its...

Page 23: ...e the space between the core and the insulating envelope being filled with oil Resin bonded paper insulated bushing A bushing in which the internal insulation consists of a core wound from resin coate...

Page 24: ...ual inspection Power factor Tan delta test Hot collar test Dete rioration of cemented joints Moisture enters Oil and or gas leaks Filler leaks out Visual inspection Power factor Tan delta test Hot col...

Page 25: ...e plate voltage rating of the bushing under test If 10kV exceeds the rating of the bushing test at or slightly below the voltage rating 3 Proceed with the test and record the results 4 Identify each s...

Page 26: ...5kV to prevent inadvertent damage to the insulation An excessive voltage may puncture the insulation and render the tap useless Some bushings do not have a power factor or capacitance tap or an isola...

Page 27: ...y and Surface Leakage if tests are made under unfavorable weather conditions Test connections GST Connect a ground wire between the test set and the host apparatus for the bushing under test 1 Install...

Page 28: ...rminal in that phase should be guarded It is also desirable to test samples of the liquid insulation Oil circuit breakers Oil circuit breakers are composed of a steel tank filled with insulating oil A...

Page 29: ...uld be recorded on the test form Enter all the nameplate information of the oil circuit breaker Identify each set of readings with the bushing se rial number Record manufacturer type or model and othe...

Page 30: ...loss indexes without the unit being defec tive or deteriorated The losses in an oil circuit breaker are different between an open circuit test and a closed circuit test because the voltage stress on t...

Page 31: ...rounded Test procedure Tests are performed at 10kV or a voltage suitable for the insulation rating 1 All tests are conducted with the breaker in the open position 2 Identify each set of readings with...

Page 32: ...s High capacitance s compared to similar tests may be the result of short circuited sections in one or more of the grading capacitors Vacuum circuit breakers These circuit breakers operate on a differ...

Page 33: ...voltage or slightly above rated voltage The tip up value is obtained by subtracting the value of the dissipation factor measured at the lower test voltage from that measured at the higher test voltage...

Page 34: ...t at the winding surface Avoid prolonged exposure to high humidity conditions before testing because such exposure may result in moisture absorption in the insulating materials It is desirable to make...

Page 35: ...s such as thyrite autovalve etc This material has a resistance that decreases dramatically with increasing volt age Arresters are effectively switching devices that serve as an insulator under normal...

Page 36: ...dependent non linear may be built into an arrester Except for the specific purpose of investigation surface leak age the exposed insulation surface of an arrester should be clean and dry to prevent le...

Page 37: ...ate contact is made with the critical areas of the insulation Pe troleum jelly or Dow Corning 4 insulating grease applied at the interface surface often helps to obtain better physical contact It may...

Page 38: ...imen Test The capacitance value from this test is C1 Figure 14 TTR Capacitor measurement The second step of the procedure is to connect the test set and the HV TTR Capacitor to the transformer winding...

Page 39: ...ZM AH02E DELTA4000 39 3 Testing power system components that no temperature change has occurred and the trans former ratio determined by this method is correct...

Page 40: ...nce 14 H High Voltage turns ratio measurements 38 Hot collar test 27 Humidity 13 I IEEE 62 1995 power factor values 11 Insulating envelope 23 Internal insulation 23 Interpretation of measurements 10 I...

Page 41: ...nnections 36 Surge lightning arresters 35 T Temperature 12 Testing power system components 16 Three winding transformers 18 Transformer excitation current tests 19 Transformers 16 Two winding transfor...

Page 42: ...eactors IEEE New York 1995 2 US Bureau of Reclamation Transformer Diagnos tics Facility instructions standards and techniques Vol 3 31 2003 3 US Bureau of Reclamation Testing and Mainte nance of High...

Page 43: ...ZM AH02E DELTA4000 43...

Page 44: ...TYPES S SI SM TYPE U 0 32 0 1 09 0 93 1 00 1 18 1 26 1 02 1 33 8 1 09 0 94 1 00 1 17 1 25 1 02 2 35 6 1 09 0 95 1 00 1 16 1 24 1 02 3 37 4 1 09 0 96 1 00 1 15 1 22 1 02 4 39 2 1 09 0 97 1 00 1 15 1 2...

Page 45: ...59 0 1 00 0 95 1 12 1 03 16 60 8 1 00 17 62 6 1 00 18 64 4 1 00 19 66 2 1 00 20 68 0 1 00 1 00 1 00 1 00 21 69 8 1 00 22 71 6 1 00 23 73 4 1 00 24 75 2 1 00 25 77 0 1 00 1 04 0 89 0 97 26 78 8 1 00 2...

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Page 48: ...d Dover CT17 9EN England T 44 0 1304 502101 F 44 0 1304 207342 E UKsales megger com Other Technical Sales Offices Dallas USA Toronto CANADA Trappes FRANCE Oberursel GERMANY Oberkulm SWITZERLAND Johann...

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