ISRAEL ELECTRIC CORP.METER TESTING LABORATORIES

DEPARTMENTSTANDARDS LABORATORY

Development

of the Electricity Metering

Laboratories

in Israel

Shalomygin Maxim

Gueta Itshak

Standards Laboratory;

Mahban Khosrow

Electronic Meters Development;

National Metering Department

Israel Electric Corporation

17 ,Halehi Street, Bnei Brak 51200, Israel.

maxims@iec.co.il

Preparing of the tests and calibrations procedures.

Calculation of the measuring and calibration uncertainties.

Training of the laboratory personnel.

Background

Electrical energy is one of the main factors for the strategic development of our country.

Proper generation and consumption of electrical energy should be based on metrological aspects.

Technological progress is impossible without metrological support.

Accredited laboratories in Israel

Electricity meters tests Laboratory

South consumpti

on departmen

t

North consumptio

n department

Standard Laboratory

External laborator

y

External laboratory

The Internationa

l Accreditatio

n Forum (IAF)

The Internationa

l, Laboratory Accreditatio

n Cooperation

(ILAC)

Israel Laboratory Accreditation Authority

(ISRAC)

The Standard Metering Laboratory of the Israel Electric Corp. maintains and develops a system of national standards for the electrical power and energy metering.

This system depends on a rigid hierarchic quality control system.

The main aim of the metering laboratory is maintaining traceability.

Traceability Chain

Precision Electricity

Meter

Laboratory Test Bench

Instrument Transform

er

Electrical Energy Measurement

Electricity Meter

Measuring Bridge

PTBNPL, PTB

Mobile Test

Bench

On site Mobile

Test Bench

Reference Transform

er

Reference Meter

Reference Meter

Reference Meter

Measuring Devices

Electricity meters and EPE meters.

Transducers and transformers for support of the EPE meters.

Adjustable power sources.

Calibration methods for the measuring system

Energy dosage, delivered to device under test.

Indirect methods to test electricity meters.

Direct calibration with standard devices.

Precision in measuring predetermines technology progress. It makes possible to develop new technologies, produce new systems and devices .

It is extremely important to reduce uncertainty of measurements .

The CMC (Calibration and Measuring Capability) of our laboratory is 150 ppm for the calibration of the electrical power and

energy meters .

Optionally we can achieve about 70 ppm.

Automation of the measuring procedures.

Unification and standardization of the different measuring system types.

Improve metrological compatibility of the measuring systems and units under test.

The reference electricity meter includes sources/references of the DC voltage and frequency sources .

They should be calibrated periodically

(at least once every 3 months.)

Storage of data of the calibrations gives the opportunity to provide statistical analysis .

Statistical analysis is an important and useful activity of our laboratory. We provide tests of hypotheses, method of maximum probability and regression analysis.

Measurement and analysis of dynamic processes. Characteristics of some physical processes depend on different dispositions and non-synchronous measuring. In these cases some processes could be regarded as random processes.

Competition and collaboration between laboratories.

Expanding the capability of the metering laboratory.

Correct calibration of the electricity meters requires compliance with the validated methods, and taking into account the influence factors.

Human factor

Power quality of the power sources

Electromagnetic compatibility (EMC) of measuring equipment, cables and external equipment.

Normal ambient conditions

Transducers, transformers and assessment equipment.

Since results of calibrations are highly sensitive to the influence factors, the metering laboratory must expand its capability to take into account the influence factors.

Methodological Expansion

Examples of the methodological expansion

*There are several schemes for electricity meter connections to the three phase network.

*Reference meters have a limited range of measuring capability.

*Reliable calibrations period depends on the drift of deviation of the unit under test from traceable values.

Tests of the drift include:

Comparison between precision EPE meters;

Test of the internal counter and generator of the specific pulses frequency;

Test of the internal meter and source of DC voltage.

Simple pair-wise comparison of the measuring results is calculated by formula:

C = R + D – B;

Where:

R – measured result of the comparison;

D – result of the calibration of the meter which counts pulses;

B – result of the calibration of the meter which generates pulses;

There are three criteria of acceptable drift level:

*C smaller than the calculated value of CMC in specified range;*Absolute difference of present and previous results of the comparisons is less than half of the annual drift limit value; *Standard square root deviation of the results of pair-wise comparisons between a few precision meters should be smaller than admissible value. Admissible value of the standard square root deviation could be calculated according to the Neiman-Pierson criterion.

These are a few practical recommendations, and I hope it will prove interesting for the different kinds of the calibration laboratories.

Thank you for your attention.

Technical Expansion

FLUKE 6100A