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1 Y.K.Nama Germany

2 Topics Meter testing practices around the world Scenario of applicable standards New findings in measurement New trends Value addition by meter testing Questions still need to be answered

3 Meter testing practices Who Test Meter Manufacturer Electric utilities in Laboratory Electric utilities at site When Meter manufacturer While manufacturing For inspection of lot Utilities Before installation During installation During service Rate of testing 100% Sample testing

4 Objective of meter testing Meter manufacturer Utilities at Laboratory To certify accuracy class of meter To follow regulatory requirements As part of purchase agreement To ensure quality of meter To ensure proper functioning & features Check Measurement accuracy Quality control & Inspection Regulatory requirements Utilities at On Site To detect tamper/solve customer complain To ensure proper functioning of meter To evaluate the installed meter population To form Basis for replacement or maintenance To follow regulatory requirement

5 Testing Practices & Method Laboratory At Sites Challanges in laboratory testing Efficient & Proper testing for large volume New design with complex features Testing of closed link meters Maintaining in-house legal metrology system Methods:-Using large test benches Utilities are going for systematic lab accreditation as per ISO Challanges in on-site testing Access to meter Testing regulation and acceptance criteria Methods:- Real load Phantom load

6 On-site testing, using existing load Reference meter with clamp on C. T. meter scanning head reference meter rotor disk SC voltage connection U1 U2 U3 N I1 I2 I3 display Clamp on CT

7 Pros-Cons of using existing load Pros Cons Economic solution Less time required and easy in testing No disturbance to meter wiring Often seen in Asian countries, Middle East, and also Where tempering is a big problem Limited Testing Highly dependant on the consumer load Does not provide basis for decision making of pass/fail Legally not recognised

8 On-site testing, using phantom load Reference meter and source scanning head meter rotor disk SC voltage connection U1 U2 U3 N I1 I2 I01 I02 display reference meter I3 I03 I1 I2 I3 I01 I02 I03 U1 U2 U3 N source

9 Pros-Cons of using phantom loads Pros Cons No dependency on the consumer load. Closer to laboratory testing. Provides good basis for decision making on performance of meter. Registration and other functional testing can be performed. Legal recognition in some countries. Advance and complex testing is possible with modern electronic phantom load Additional cost of source. Meter needs to be reconnected after testing Often Seen in European countries

10 Testing intervals Vary from country to country Germany, Switzerland, Austria 16/8 years India :-<2 years for bulk & 5 years for domestic consumer Hongkong, Croatia, colombia :- No planned testing Singapore, Russia once in a year for bulk consumer Consumer complained basis

11 Applicable standard For laboratory testing IEC , IEC , 21,22, 23 For on-site testing CEA guide line and IS is a good steps in this direction accuracy of portable reference standard & other metrological properties. What need to be checked Same as IEC standard with/without additional allowance MID (EN50470) approach can be very useful International efforts for test equipment & test procedure IEC : For Stationary Meter Testing Equipment IEC : For onsite testing

12 New findings in measurement Due to small DC component in voltage circuit Experience from european utiltities Due to mixed core Frank Hermann :- Current Static Watt-hour meters- Critical combined cores CT and DC test Metering International Issue 3/2007, Page 121 Reactive measurment is inappropriate in the presence of harmonic and further affecting KVA demand calculation PF calculation

13 New trends in on-site testing Expanded beyond the accuracy test Connection check Burden measurement Harmonic analysis Detailed about the harmonic Who generated this Accuracy testing of instrument transformer Complete installation testing

14 The complete installation testing Reference Meter Scanning head mounted on the meter and connected to reference Standard k l Special adopter K L Current Sensor L1 Voltage Sensor Sensors are directly connected to reference standard and measure the primary side voltage, current

15 What bring the onsite testing. Reduction in energy tampering Finding defective meters Consumer satisfaction Finding connection fault Correction of CTVT ratio Correction in CTVT burdens Detailed error analysis in the presence of harmonic

16 Further value addition... Statistical evaluation of meter type, brand, performance of meters after given years of operation, which further helps deciding on test interval.see the detailed report carried out by Swiss utility Qualitative feed back for future procurements of meters and instrument transformers. Detection of theft through regular and extensive testing at site. See DERC report on CPRI testing conducted in Delhi Screening of a particular area or zone so that surveillance interval/frequency of particular zone can be increased or decreased.see how NDPL and BSES has developed logic to filter out such type of meters In terms of customer confidence, minimizing customer complains & legal cases, and image building.

17 What meter testing can do??? No Solution through technology for the social devil Area where systematic testing can do value addition

18 Question still need to be answered Performance of CTVT in the presence of harmonic and actual HV environment Performance of new energy meter after warranty period Performance of testing equipment under the electromagnetic interference (EMI/EMC ) Life /reliability of meter

19 Thank you for attention Look forward for your querries/question