Biddle CTER-91_UG 电路图.pdf

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1、 Part #- 14356 Rev. 4 Date 6/19/02 INSTRUCTION MANUAL For CURRENT TRANSFORMER EXCITATION TEST SET MODEL CTER-91 It is essential that this instruction book be read thoroughly before putting the equipment in service. RadioFans.CN 收音机爱 好者资料库 Part #- 14356 Rev. 4 Date 6/19/02 REVISION HISTORY Revision E

2、CN # Date 1 26127 10/26/94 2 26460 5/25/95 3 28099 6/30/98 4 29340 6/19/02 IMPORTANT The information and data contained within this instruction manual are proprietary with AVO MULTI-AMP Corporation. The equipment described herein may be protected by one or more U.S. letters patent. AVO MULTI-AMP spe

3、cifically reserves to itself all rights to such proprietary information as well as all rights under any such patent, none of which is waived by the submission of this instruction manual to anyone. The recipient, if a Government agency, acknowledges that this instruction book and the equipment descri

4、bed were procured with Limited Rights to technical data as described in ASPR 9-203 (b). Copyright AVO MULTI-AMP Corporation, 1992 RadioFans.CN 收音机爱 好者资料库 TABLE OF CONTENTS SAFETY PRECAUTIONS . 1 PRINCIPLES OF OPERATION. 2 GENERAL DESCRIPTION. 2 DESCRIPTION OF CONTROLS. 2 SERVICING . 3 DESCRIPTION OF

5、 TESTS . 4 OPERATING INSTRUCTIONS . 7 Ratio Test. 7 Polarity Test. 8 Saturation Test. 9 METROLOGY AND REPAIR DATA. 10 CALIBRATION CHECK 11 APPENDIX. 13 FIGURE 1-SATURATE AND RATIO TEST. 14 FIGURE 2-POLARITY TEST. 15 FIGURE 3-MULTI-RATIO CT TEST. 16 FIGURE 4-TESTING BUSHING CTS IN CIRCUIT BREAKERS. 1

6、7 FIGURE 5-TESTING BUSHING CTS IN TRANSFORMERS. 18 FIGURE 6-TEST SET CONNECTIONS . 19 FIGURE 7-SATURATION CURVES. 20 FIGURE 8-SATURATION CURVES. 21 SCHEMATIC DIAGRAM . 22 INDEX. 23 RadioFans.CN 收音机爱 好者资料库 1 SAFETY PRECAUTIONS Please read this manual carefully and completely prior to using the unit.

7、Read and understand all safety, caution and operation instructions before attempting to use this unit. Should a situation arise that is not covered in the general or specific safety precautions, contact your local Multi-Amp representative or Multi-Amp Corporation, Dallas, Texas. Repairs should be ma

8、de with the unit disconnected from the power source. Should repair or adjustment of energized equipment be required, under no circumstance should the work be done alone. Additional personnel should be present to render aid if required. NOTE: MAKE SURE ALL CONNECTIONS ARE MADE PROPERLY TO AVOID ACCID

9、ENTAL OPENING OF THE CURRENT TRANSFORMER SECONDARY WHICH CAN LEAD TO DAMAGE OF THE TRANSFORMER UNDER TEST. Model CTER-91 is designed for a maximum continuous output of 2.0 amperes at 600 volts. The instrument incorporates circuitry to disable the output if excessive current is generated. It is good

10、practice, however, to limit the output current to the design maximum. CAUTION: Do not exceed 2.0 amperes output to prevent the possibility of damage of the instrument. 2 PRINCIPLES OF OPERATION GENERAL DESCRIPTION Multi-Amp Model CTER-91 is lightweight, portable unit for performing excitation, ratio

11、 and polarity tests on current transformers using the voltage comparison method. Utilizing the latest technology, Model CTER-91 provides a variable voltage output and precision instrumentation for testing single and multi-ratio CTs. All three tests, excitation, ratio and polarity, can be performed w

12、ithout changing any leads. Current transformers may be tested in their equipment configuration, such as being mounted in transformers, oil circuit breakers or switch gear. This eliminates the need to remove bushings or remove CTs from switchgear. Of course, it is necessary for the equipment to be to

13、tally isolated from the electrical system prior to testing. DESCRIPTION OF CONTROLS Power ON/OFF Switch Energizes the test set. MAIN OUTPUT ControlA variable autotransformer with four ranges, 0-40 volts, 0-150 volts, 0-600 volts and 0-1000 volts which provides continuous control of the output voltag

14、e. The variable transformer must be at zero before the unit can be initiated. FINE OUTPUT Control A vernier for finer control of the output voltage. This vernier controls 10% of the MAIN OUTPUT value. The vernier control is connected to subtract from main output. RUN/HOLD Switch In HOLD mode, the te

15、st set will freeze the latest readings on the AC Ammeter, AC Secondary Voltmeter, and AC Primary Voltmeter. In RUN mode, the meters will provide continuous update. VOLTAGE RANGE Switch Selects either OFF, 0-40 volt, 0-150 volt,0- 600 volt or 0-1000 volt range. TEST SELECTOR Switch Selects the desire

16、d test to be performed. CB-2 A 12 ampere Push to Reset breaker which protects the main output transformer. PRIMARY/EXTERNAL VOLTS Voltmeter Measures the voltage on the primary of CT under test. If EXT VOLTS function is selected, it reads voltage present at EXT VOLTS binding posts. 3 SECONDARY VOLTS

17、Voltmeter Measures voltage in the output circuit that is connected to the secondary of the CT under test. Ammeter Measures current in the output circuit. EXT AMPS Binding Posts Provides a means of connecting an external ammeter in the circuit. It is not to be used to measure an external ac circuit.

18、Note: Leave sliding short in place except when using external series ammeter. EXT VOLTS Binding Posts Enables the primary voltmeter to read an external ac voltage of 0-1000 volts when the selector switch is in the external voltmeter position. GND - Ground Binding Post In addition to an input source

19、ground an external ground terminal is provided to ensure that the test set chasis is grounded. X1, X2, H1, H2 Binding Posts Connects the CT under test to the test set. SERVICING This test set utilizes straightforward circuits and components which require little or no service except for routine clean

20、ing, tightening of connections, etc. The following maintenance is recommended: 1. Open the unit every six months and examine for: a. dirt b. loose connections 2. Remove dirt with dry, compressed air or a vacuum cleaner. 3. Tighten all connections, especially on the larger current wires. 4. Check the

21、 carbon wiper on the output powerstat, it should not be too loose. 4 DESCRIPTION OF TESTS Ratio Test The ratio is defined as the number of turns in the secondary as compared to the number of turns in the primary. Apply one volt per turn to the secondary of the CT under test. Raise voltage slowly whi

22、le observing meters. When one volt per turn has been reached on the secondary voltmeter, one volt should appear on the primary meter. If the CT saturates before one volt per turn is reached, apply a smaller voltage which is a convenient fraction of one volt per turn. (e.g. .5v per turn). The Primary

23、 voltmeter should read the chosen fraction of a volt. If a multi-ratio CT is being tested, the selector switch can be placed in the External Meter position. The primary voltmeter can be used to read the voltage between taps on the secondary winding while a known voltage per turn is applied to the wi

24、nding, either between taps or to the full winding. CAUTION: TO PROTECT AGAINST INSULATION FAILURE, DO NO EXCEED MORE THAN 1000 VOLTS ON ANY OF THE SECONDARY WINDINGS OF THE CT UNDER TEST. Leads should be connected to the test set EXT VOLTS binding posts only when the selector switch is in the EXT ME

25、TER CONNECTION position. Polarity Test Indicates the designation of the relative instantaneous directions of the currents entering the primary terminals and leaving the secondary terminals during most of each 1/2 cycle. Switch the rotary switch to the SEC ? 10 + PRI position. Raise the secondary vol

26、tage to a known voltage per turn or to a percent of volts per turn that will not saturate the CT. Voltage displayed on the primary meter should be secondary voltage divided by 10 plus the primary voltage. Switch the rotary switch to SEC ? 10 - PRI position voltage displayed on the primary meter shou

27、ld be secondary voltage divided by 10 minus primary voltage. Example: With a CT with a ratio of 120:1, 600:5 current ratio, and one half the voltage applied voltage or 60 volts, the polarity is correct if the primary meter reads 6.5, which is 60 divided by 10 plus the voltage from the primary meter.

28、 Switch the TEST SELECTOR Switch to SEC ? 10 - PRI and the reading should be 5.5 The divide by 100 positions may be used in the same manner. SEC ? 100 + Primary = (.6 + .5) = 1.1 volts SEC ? 100 - Primary = (.6 - .5) = .1 volts Saturation Test IEEE defines saturation as the point where the tangent i

29、s at 45? to the secondary exciting amperes. (See Figures 7 and 8). 5 With the test set secondary binding posts X1 and X2 connected to the CT secondary and the H1 and H2 binding posts connected to the CT primary, increase output observing the ammeter and secondary voltmeter. Increase voltage until a

30、small increase in voltage causes a large increase in current. Most CTs will saturate at 1 amp or less and 600 volts or less. Note: It may be necessary to plot a curve to detect the saturation point. See Figures 7, 8 and ANSI/IEEE C57.13 for illustrations of typical curves for Class C transformers. T

31、est Preparation Notes Notes on the Theory of Current Transformer Ratio and Polarity Testing Using Secondary Voltage Injection. 1. Carefully observe the polarity when connecting the CT. 2. Be careful not to saturate current transformer during ratio or polarity tests or results will be in error. 3. Ap

32、ply no more than rated voltage, as indicated by the turns ratio, to the secondary taps being tested. Example: A 600:5 CT implies a 120:1 turns ratio. Therefore, 120 volts impressed on the entire CT secondary winding should produce 1.0 volt reading, H1-H2 terminals, on the primary voltmeter. If satur

33、ation occurs, reduce the impressed voltage to 60 volts which should read 0.5 volts on the primary meter. 4. The test leads connecting the meters to the H1-H2-H3 terminals of the device under test are shielded and the shields nearest the meters are tied together and grounded. 5. When testing CT ratio

34、s, where CTs are connected INSIDE the delta winding connection, only 2/3 voltage will be measured on the phase to phase primary. This is a result of the voltage dividing network created by the connection. (See drawings). 6 OPERATING INSTRUCTIONS Set-up controls before testing Control Position Power

35、ON/OFF OFF Output Controls Zero (counterclockwise) TEST SELECTOR Switch Saturate and ratio test TEST VOLTAGE Switch As required RUN/HOLD Run Range Switch As required CAUTION: FOR OPERATOR AND EQUIPMENT SAFETY, MAKE SURE CURRENT TRANSFORMERS ARE DE-ENERGIZED BEFORE ANY TESTING IS STARTED. Ratio Test

36、1. Refer to the appropriate Figure in the Appendix for test connections. 2. Verify that the Power ON/OFF switch is OFF. Connect the test set to a suitable source of power (as indicated on the nameplate) and ground. 3. Connect the test set secondary output binding posts X1 and X2 to secondary of curr

37、ent transformer X1 and X2. Observe polarity marks on the CT (X1 on the CTER-91 is polarity). 4. Connect the test set primary binding posts H1 and H2 to CT primary bushings H1 and H2. Observe polarity marks (H1 on the CTER-91 is polarity). 5. Turn Power ON/OFF switch to ON. 6. Slowly increase MAIN OU

38、TPUT control to apply approximately 100% - 105% output voltage to the transformer under test. Use FINE CONTROL to adjust to 100% output voltage. Example: A 300:5 transformer implies a turns ratio of 60:1. Therefore, 60 volts impressed on the entire secondary should produce 1.0 volts on the primary v

39、oltmeter. If saturation occurs reduce impressed voltage to 30 volts, which will produce 0.5 volts on the primary. (In some cases, a further reduction of the 7 impressed voltage might be required to keep the CT from saturation. The procedure remains the same, regardless of the 8 impressed voltage val

40、ue). 7. When the expected value is read on the secondary voltmeter, a voltage will appear on the primary voltmeter. Switch the RUN/HOLD switch to HOLD. 8. Slowly decrease OUTPUT control to zero and record data. 9. Return RUN/HOLD switch to RUN. Polarity Test 1. Move TEST SELECTOR Switch to SEC ? 10

41、+ PRI position. 2. Refer to the appropriate Figure in the Appendix for test connections. 3. Verify that the Power ON/OFF switch is OFF. Connect the test set to a suitable source of power (as indicated on the nameplate) and ground. 4. Connect the test set secondary output binding posts X1 and X2 to s

42、econdary of current transformer X1 and X2. Observe polarity marks on the CT (X1 on the CTER-91 is polarity). 5. Connect the test set primary binding posts H1 and H2 to CT primary bushings H1 and H2. Observe polarity marks (H1 on the CTER-91 is polarity). 6. Turn Power ON/OFF switch to ON. 7. Slowly

43、increase OUTPUT control to a known voltage. 8. Switch the RUN/HOLD Switch to HOLD. Return OUTPUT control to zero. Read and record the values. 9. Return RUN/HOLD Switch to RUN. Polarity is correct if the primary voltmeter indicates the secondary voltage being applied divided by ten plus voltage feeding back from the primary. For example, using a 200: