Chapter-15 Testing and Commissioning of Electricity Energy Meters

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TESTING AND COMMISSIONING OF ELECTRICITY ENERGY METERS

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<p>Chapter-15</p> <p>TESTING AND COMMISSIONING </p> <p> OFELECTRICITY ENERGY METERS</p> <p>15.1 ENERGY METERS COMMISSIONING.</p> <p>A short note on Commissioning as applied here serves as a key to open this chapter, in order to signify its importance and simultaneously to literate the reader being Testing and Commissioning person, to feel his responsibilities. Elaborate discussion on testing of energy meters will then be followed after this brief glimpse. </p> <p>Commissioning is carried out to testify the incorporated metering scheme along with proper working of the associated wiring and ancillary equipment and to validate it. Commissioning is considered to be essential when set-up was laid down initially or any change or alteration has been incorporated subsequently at later stage, in existing metering scheme or wiring re-routing. Testing and Commissioning Engineer certifies that the scheme is appropriate to the objective and test it thoroughly, in order to certify the correctness of associated wiring and intervening protection, healthiness and also declare that the accuracy class of metering confirms to the manufacturers specifications. He also certify that the complete lay out also confirms to as built drawing which will be the replica of schematic diagram. After certification, the case has been put up for approval from the competents concerned for energization. Alternatively, commissioning is concerned about, complete functionality of the metering scheme along with all the necessary peripherals, fully prepared and kept as ready to energize. 15-115.2.1 ENERGY METER TESTING.</p> <p>The testing of electricity energy meters for commercial work has been standardized initially by the provisions of the Electricity Supply (Meters) Act, 1936 in the United Kingdom, encompasses different clauses covered under B.S.S (British Standards Specifications) commonly known as B.S.S.</p> <p>.</p> <p>Similarly Working on the parallel platform, later on, International Electro-Technical Commission (I.E.C) regulate and standardize, among other, The Testing of the Electricity Energy Meters Act 1956 introduced in France, subsequently revised and reached in present shape in 1986 under S.I units (stands for Standards de International or International Standards) and now accepted in all the Europe, commonly known as S.I Units. For example, Accuracy Class: Active Energy 0.2S or 0.5S (IEC 62053-22), Reactive Energy: Class 2, 3 (IEC 62053-23), calibrated up to 0.5 %, Apparent Energy: Calibrated up to 0.5 % etc. and lay down different provisions regarding testing of the electricity energy meters.</p> <p> The Electricity Commissioners (in the United Kingdom) issued a series of papers*, which contain details of the methods of testing and should be employed and the approved apparatus which should be installed in meter-testing stations / labs for the purpose of such tests. These papers should be studied by the reader who is interested in the subject of energy meters testing. Due to scarcity of space, only few of the more important provisions can be given here,</p> <p>* E.g. Electricity Supply (Meters) Act, 1936 : approved apparatus for testing stations, etc.; Explanatory Memorandum concerning the Testing of Electricity Meters; The apparatus approved for use in Meter Testing Stations, etc.; Further Explanatory Notes concerning the Testing and Certification of Electricity Meters, etc.: Supplementary Notes in Amplification of the Explanatory Memorandum, etc, published by H.M. Stationery Office, United Kingdom.</p> <p>15.2.2APPROVED APPRATUSDealing with the approved apparatus first, this is listed as follows:-</p> <p>15-2</p> <p>Standard Apparatus</p> <p>D.C. Potentiometer.</p> <p> Standard Testing Set of desired Accuracy Class. i.e. 0.5, 0.1 or 0.02 etc.</p> <p> A.C. Rheostat for having Proper input voltage to the testing set.</p> <p> Substandard Apparatus </p> <p>Indicating Wattmeter.</p> <p>Rotating Meter.</p> <p>Phase Sequence detector.</p> <p>Ammeter.</p> <p>Voltmeter.</p> <p>Clamp-On Multimeter</p> <p>Electrolytic Ampere-Hour Meter.</p> <p>Time Standard</p> <p>Ships Chronometer or Pendulum-Type Clock.</p> <p>Time Substandard</p> <p>Stop watch or some other timing device.</p> <p>Tools Required </p> <p>Screw driver set.</p> <p>Precession Screw drivers set.</p> <p>Pair of pliers and nose pliers.</p> <p>Wire Stripper.</p> <p> Screw driver type tester.</p> <p>Banana plugs, crocodile clips, thimbles (sufficient stock).</p> <p>Connecting wires, (ample stock).</p> <p>Three Phase / Single Phase extension boards with earth wires.</p> <p>Soldering iron with stand holder, and soldering wire / Rasin.</p> <p> Hand Drill Machine with steel/ concrete / wooden bits.</p> <p>Air Blower, Cleaning brushes, Cotton swabs.</p> <p> Grease, WD-40 for loosening of rusted parts / nut &amp; bolts.</p> <p>15-3</p> <p>Contact cleaner.</p> <p> Emery / Sand paper.It is laid down that the rheostat and potentiometer shall be tested at intervals at the</p> <p>National Physics Laboratory, and that the other apparatus shall be tested at regular intervals of time (i.e. Annually, or bi-annually) against some standard apparatus or against substandard indicating instruments at stated intervals.</p> <p>Specifications are given for the approved apparatus, and these include constructional requirements and allowable accuracy limits.</p> <p>15.2.3 PERSONNEL PROTECTIVE EQUIPMENT (P.P.E)</p> <p>As per international standards, P.P.E : Personnel Protective Equipment is as essential as breathing is to life. No job is permitted without the wear of the properly maintained P.P.E. This is for the individual betterment and concern about overall safety and simultaneously lay downs favorable working environment for all, and can be attributed as hereunder.</p> <p>The priority level and work methodology should adhere to;1. Personnel safety.</p> <p>2. Equipment safety.</p> <p>3. Then Comes the Work. </p> <p>The objective of safety is to provide such a means as to protect the individuals from any possible hazard and provide a healthy working environment to get maximum output from the limited and highly expert human resource. Then comes the equipment safety : Provide such a safe working practices as to protect the costly equipment against any possible damage. By protecting the equipment, two ultimate objectives are attainable:</p> <p>15-4</p> <p>1. Suppress the wide spread catastrophe, so that major collapse of the system could be averted, giving rise to stable continuity of service and hence better consumer confidence.</p> <p>2. Could save heavy financial and time constrained loss, which improves upon the cost (minimized) and minimizing the planned outages.Having all of the foregoing practices, there comes the execution of work. As every individual have strived to the noble cause of providing a shield against hazards, he actually endeavor to better service quality and to improve upon building consumer confidence. Additionally every one feels the responsibility, protecting the environment, by saving against the hazards, and reduction in material processing (as mass of the universe is constant, so appearing new things merely is the fast material processing i.e. simply decomposing and recomposing).Now Came to the essentials to P.P.E (Personnel Protective Equipment):Helmet: To provide coverage to head against falling / hitting objects.</p> <p>Pair of Gloves. : Protects hands against mess and stresses. Pair of Goggles. : Protects eyes from foreign bodies. Chest Shield.: Protects chest against impacts.Jute Matting.: To provide electrical insulation while on work. </p> <p>Safety Shoes: Steel toed, safety shoes, protects feet from fallen heavy Loads.</p> <p>Harness Belt: To provide safe overhead working.</p> <p>15.3SAFETY SLOGANS : Here are few Safety Slogans; they are worth it, on the subject of Safety. These Quotes, emphasis the importance of Safety, at our work place, daily lives and all around us. It is really a life. </p> <p> Simply: Walk like you are on a slippery surface. Additionally: Safety never takes a holiday.15-5Safety Slogans in English. Chance takers are accident makers. Courtesy and Common Sense Promote SAFETY.</p> <p> Do your work with pride, put safety in every stride. Don't be a fool, cause safety is cool, so make that your rule. Don't be safety blinded, be safety minded. To avoid a scene keep your work place clean. Working without safety is a dead end job. Ignoring a warning can cause much mourning. The greatest gift you can give your loved ones is to come Home Safely. My job provides my paycheck, but SAFETY takes me Home! Reduce Incidents With a Steady Diet of Safety! Winter, Spring, Summer, Fall: Play it safe throughout them all! The freedom to choose....choose to work safely. If someone trip, he will be not in safe grip. Wear Safety Gears, Protection Everywhere. People don't Plan to Fail.........They Fail to Plan!</p> <p> Safety doesnt slow the job down but mishaps do.</p> <p> Safety is our mission, Not an intermission. Walk like you are on a slippery surface. The right shoes will save your toes, may be your Life!</p> <p> Hands are my friends along with Policies and Procedures. Remember! Dont Dare Take Care, Observe Safety Everywhere. There is no face like Your Own, wear face Protection. Safety is a cheap and effective insurance. Safety never takes a holiday.15-6Safety Slogans in Urdu. ! Courtesy: Mr.Sohail, Manager Electrical,</p> <p> Engro-Gen, Ghotki, Sindh, Pakistan.</p> <p>5.4 METHODS OF TESTS ;</p> <p>15.4.1 ELECTRO-MECHANICAL ENERGY METERS.For motor meters, three methods of test are dealt with, as described hereunder;</p> <p>Method A;</p> <p>Long-period dial tests, using substandard rotating meters.</p> <p>Method B;</p> <p>(a) Tests (other than long-period dial tests) using substandard rotating meters.</p> <p>(b) One long-period dial test.</p> <p> Method C; (a) Tests by substandard indicating instruments and stop watch.</p> <p>(b) One long-period dial test.</p> <p>15-5It is laid down that Method C alone is to be used for testing direct current motor meters.</p> <p>All meters are to be tested (a) at the lowest percentage of their marked current specified in the limits of error for meters of their class under the electricity (Supply) Acts; (b) at one intermediate load; and (c) at the highest percentage of marked current specified in the limits of meter.</p> <p>In the case of a.c meters, they are also to be tested at marked current and marked voltage at 0.5 power factor lagging. </p> <p>Watt-hour must also be tested for creep by applying 10 percent overvoltage to the voltage coil, the main circuit (current-coil circuit) being open. The meter must not run under these conditions.</p> <p>It will be observed that the testing engineer has the liberty of choice between the above mentioned three methods of test (in a.c. meters), but all three methods involve at least one dial test.</p> <p>Numerous sorts of the tests of electricity energy meters are applicable in market. From manufacturer to end users, these tests are to affirm assurance that the behavior of these meters remain satisfactory under prevailing market conditions and to ensure their endurance under toughest of operating conditions. Apart from all these assurances, majority from the lots get defective and provides way out to manufacturer and applicator (end users) to sit together in order to fix the reasons behind these failures and improve upon the quality, to have a customer satisfaction. Despite these challenges, the Testing Engineer has given the responsibility to sort out these type of problems in the field and should have a competency level of such an extent, that he should be able to convince and tackle the stakeholders, in order to provide viable solution to these problems. However, these tests are mainly classified under two sub-sectors.</p> <p>1) In-House or Laboratory Testing: </p> <p>a)Also covers In-Door Testing, Production Testing, Quality Control Testing commonly known as FAT (i.e. Factory Acceptance Tests).</p> <p>15-8b) With-Stand Tests: Electrical, Mechanical / Thermal and Environmental Tests, such as High Frequency interference with-stand test, Dielectric strength with-stand tests, Shock / Impact with-stand tests, Thermal stress with-stand tests, Temperature, Humidity and Rain with-stand tests. </p> <p>c) Preventive Maintenance Tests / Routine Tests, etc.</p> <p>Such as Dial Tests, Creepage Tests and Accuracy Tests, either off-load or on-load tests, etc.</p> <p>2) Out-Door Tests / Field Tests</p> <p>a) Routine / Preventive Maintenance Tests.</p> <p>Bi-Annually or Annual Tests.</p> <p>Such as Dial tests, Creepage tests and Accuracy tests either off-load or on-load tests, etc.</p> <p>b) Sector Specific Tests.</p> <p>To cover up subsequent difference of recording (after commissioning), between Primary and Back-up Metering due to errors introduced by instrument transformers i.e. C.Ts and P.Ts, and to fix the problem. i.e. to adopt a compensation factor or to add the compensation resistors in C.Ts and P.Ts circuits.</p> <p>Or</p> <p>Drastic change in recording by the energy meter has been observed.</p> <p>Or</p> <p>Improper recordings of some measurands which demands re-testing and for fixing the problem (i.e. improper recording of the reactive energy when import of active energy is too low on a high tension, less loaded, longer line or too low a power factor results in high penalties to consumers) i.e. re-programming the energy meter, for recording of reactive energy quadrant wise for proper reactive energy recording.</p> <p>15-9Or </p> <p>Summation Metering or data-logger requirements may arise, when multi-feed in and out arrangement is there for the dispersal of power at the interconnection point i.e. grid station of the power house. </p> <p>* 2b above applies generally to digital energy meters.</p> <p>Though there is no sharp line of demarcation between these tests, their suitability and provision is solely detrimental to Pre-facture / utility policy and how much utility wants to invest-in, on testing and commissioning phases of the metering. As a guide line, where un-visible financial fragmentation has been carried out in electrically integrated infrastructure, the pricing of energy quantum transaction is important rather than the cost of metering facilities. So emphasis should be on the recording of energy transactions, but not on the cost involvement on lay downing the metering structure , in this way, financial disputes ( worth billion of rupee) can be reduced among different utilities and smooth operation of the system is possible. Alternate Classification ;</p> <p>Another classification for testing of the energy meters is as under:</p> <p>D.C Energy Meter Testing.</p> <p>A.C Energy Meter Testing.</p> <p>Active Energy Meter Testing.</p> <p>Reactive Energy Meter Testing.</p> <p>Special Purpose Meter Testing.</p> <p>15.4.2 SOLID STATE / DIGITAL ENERGY METERS ;OPENING A DIALOGUE TO DECIDE WHICH WAY TO ADOPT; .</p> <p>With static / digital energy meters, the manufacture of components, previously under the control of the manufacturer in respect of electromechanical designs, is largely in the hands of specialist electronic components manufacturers. 15-10This means that to ensure the requisite, high reliability, energy me...</p>