P-E-01—Procedures for calibrating and certifying electricity meter calibration consoles pursuant to EL-ENG-12-01—Requirements for the certification of measuring apparatus—electricity meter calibration consoles

6.0 Procedures for the assessment of technical requirements
(EL-ENG-12-01, s. 6.0) (part 2 of 2)

6.3 Mechanical requirements (EL-ENG-12-01, s. 6.3) (part 2 of 2)

6.3.5 Operating mode (EL-ENG-12-01, s. 6.3.6)

6.3.5.1 Guidelines

The requirement set forth in section 6.3.6 ensures that meters can be verified with their current circuits connected in series and their voltage circuits connected in parallel. Some calibration consoles facilitate this mode of testing with provisions for physically making the appropriate connections. In this case, all current circuits are energized from the same source and voltage circuits are also energized from the same source. Other consoles operate with independent isolated amplifier circuits to each coil of a MUT. The independent amplifiers energize the coils of a MUT in a simulated series/parallel configuration. This procedure checks the proper functioning of both methods.

6.3.5.2 Procedure for the assessment of the operating mode
  1. Review operating manuals or schematics if required and determine whether the console connects meter coils in a true series/parallel configuration or whether it simulates a series/parallel configuration.
  2. If the console connects meter coils in a true series/parallel configuration, no further testing is required.
  3. If the console simulates a series/parallel configuration, follow the steps outlined below to verify this feature.
  4. Place shorting bars in all but one of the MUT positions.
  5. Place the test socket in one MUT position.
  6. Ensure the console is operating in simulated series/parallel mode by enabling that function.
  7. Set up the console for testing a three-element meter with the voltage set to the highest test voltage used for testing meters, and the current set to the highest test current used for testing meters (if the highest test current used for testing meters is greater than 50 amps, use 50 amps for this test). If the console does not use all three elements for meter testing, the unused elements need not be tested (e.g. a console used only for testing single-phase meters need only have the left and right elements tested, the middle element may be excluded from this test).
  8. Using the appropriate leads, connect the Radian standard to the "Left" current circuit of the test console, and to the "Left" voltage circuit of the test console. Ensure all of the other current circuits are shorted at the test socket.
  9. Set the Radian standard to measure voltage, energize the MUT position and record the voltage. Set the Radian standard to measure current and record the current.
  10. Repeat step (9) for each of the voltage and current circuits. This step can easily be combined with the following steps.
  11. Set the Radian standard to measure "watts". Set the console for a "Series, 0.5 power factor test" and energize the MUT position. Record the watt reading and de-energize the MUT test position.
  12. Leaving the current circuit as it is, connect the Radian standard to the "Middle" voltage circuit of the calibration console and repeat step (11).
  13. Leaving the current circuit as it is, connect the Radian standard to the "Right" voltage circuit of the test console and repeat step (11).
  14. Connect the Radian standard to the "Middle" current circuit of the test console, and to the "Left" voltage circuit of the test console. Ensure all of the other current circuits are shorted at the test socket.
  15. Repeat steps (11) to (13).
  16. Connect the Radian standard to the "Right" current circuit of the test console, and to the "Left" voltage circuit of the test console.
  17. Ensure all of the other current circuits are shorted at the test socket.
  18. Repeat steps (11) to (13).
6.3.5.3 Remarks

The watt, voltage and current readings are to be within the tolerances specified in Table 1 of section 6.4.3 of EL-ENG-12-01. The spread of the watt, voltage and current readings between the elements must also be within the tolerances specified in Table 1, section 6.4.3 of EL-ENG-12-01. In the Operating Mode section of the worksheets record whether the console is capable of series-parallel testing, whether it simulates series-parallel testing and whether it satisfies the requirements of EL-ENG-12-01 for series-parallel testing.

6.3.6 Individual elements (EL-ENG-12-01, s. 6.3.7)

6.3.6.1 Guidelines

Calibration consoles are required to be able to test individual elements of meters. This test is performed on meters in order to determine if there is a balance between the errors of individual elements. When evaluating a console for individual element test capabilities, it is important that the test load applied to each element from the console be the same. In the case of manual consoles, this is not an issue since the operator sets all loads. Manual consoles that have all of the elements marked on control switches will be assessed for their correct identification and use. A semi-automatic or fully automatic console, however, is to be evaluated to ensure loads are applied consistently. A console is evaluated by setting the load to the highest current test point or 50 amps, whichever is lower, and the lowest current test point used for verifying meters.

6.3.6.2 Procedure for the assessment of individual elements for non-manual operating consoles
  1. Connect three ammeters or one Radian standard to the left, right and middle current circuits of the test socket. If the console is to be certified for meters that do not use the middle current circuit, the ammeter does not have to be connected in that position.
  2. Place shorting bars in the remaining MUT to allow testing in series.
  3. Energize the console and set the current to operate on the "Left" current element at the highest current test point used for verifying meters or to a maximum of 50 amps, whichever is lower. This initial setting will be set by the operator and cannot be changed or adjusted for semi-automatic consoles.
  4. Record the value of the current in the worksheet for the "Left" current element. If using a clip-on ammeter, clip on the left current element and record the value on the worksheet. Clip on the other elements to ensure there is no current flowing in the other elements.
  5. Switch the highest current as established in step (3) to the "Right" current element using the correct switching operation procedures for the test console.
  6. Record the value of the current in the worksheet for the "Right" current element. If using a clip-on ammeter, clip on the right current element and record the value on the worksheet. Clip on the other current elements to ensure there is no current flowing in the other elements.
  7. Switch the highest current as established in step (3) to the "Middle" current element if this element is used for verifying meters.
  8. Record the value of the current in the worksheet for the "Middle" current element. If using a clip-on ammeter, clip on the middle current element and record the value on the worksheet. Clip on the other current elements to ensure there is no current flowing in the other elements.
  9. Switch the highest current as established in step (3) for series operation using the correct switching operation procedures for the test console.

    Note: If using a Radian standard ammeter with the inner, outer and middle current elements connected to each tap, do not apply a current that will exceed the rating of the standard when all three taps are used.

  10. Record the value of the current in the worksheet for the total current value of the series circuit divided by the number of elements measured. If using a clip-on ammeter, clip on each current element and record the average of the elements measured on the worksheet.
  11. Repeat steps (3) to (10), substituting the lowest current test point used for verifying meters for the highest current test point and record these values on the worksheet.
  12. Record on the worksheets whether regulators were on or off during this test.
6.3.6.3 Procedure for the assessment of individual elements for manual operating consoles
  1. Connect three ammeters or one Radian Standard to the "Left", "Right" and "Middle" current circuits of the test socket. If the console is to be certified for meters that do not use the middle current circuit, the ammeter does not have to be connected in that position.
  2. Energize the console and set the current to operate on the "Left" current element at a convenient current test point used for verifying meters.
  3. If using a clip-on ammeter, clip on the left current element. Clip on the other elements to ensure there is no current flowing in the other elements.
  4. Switch the current as established in step (2) to all the other appropriate current elements using the correct switching operation procedures for the test console. When switching the current to the other elements, determine whether the switches are correctly labelled and the console is capable of individual element testing.
6.3.6.4 Remarks

The difference between the values of the current recorded on the individual current elements and the series current element values measured are not to be greater than 2.0 percent of the nominal current setting. If this tolerance is not met, the console may be certified to be used as a manual console only.

6.4 Procedures for the assessment of electrical requirements (EL-ENG-12-01, s. 6.4)

6.4.1 Creep switch (EL-ENG-12-01, s. 6.4.1)

6.4.1.1 Guidelines

Most calibration consoles are equipped with a creep switch in order to reduce the current supplied to the MUT positions to zero. In some circumstances, the current is not entirely reduced to zero. This procedure determines if there is an unacceptable amount of current passing through the MUT positions while the creep switch is engaged. If the switch does not function to the tolerance pursuant to the requirements, the console certificate will indicate that the creep switch is not to be used. An alternate method of determining if a meter creeps may be established.

A watt-hour standard is used to determine if any energy can be registered while the creep switch is engaged. Registration outside the limits established in EL-ENG-12-01 indicates that the creep switch is not functioning as required. Calibration consoles are to indicate when the creep switch or other such device is activated.

6.4.1.2 Procedure for the assessment of the creep switch
  1. Connect the voltage and current inputs of the watt-hour standard to a MUT position on a console. Use a socket adapter if necessary.
  2. Install shorting bars in all other MUT positions.
  3. Apply the test voltage to each MUT position.
  4. Set the console for series current operation.
  5. Energize the console and set the voltage to the highest voltage used for verifying meters.
  6. Set the current to the lowest current value used for verifying meters.
  7. Enable the creep switch to reduce the current supplied to the MUT position to zero.
  8. Verify that a status indicator of an acceptable type (e.g. indicating light, on-screen indication, or current indicating instrument reduces to zero, etc.) shows that the creep switch is active.
  9. Record any watt-hour energy registration indicated on the standard during a fifteen- minute interval.
  10. Calculate the allowable energy registration using the following formula:
    Whmax =  (0.1% × (volt max) × (current min × 15) ÷ 60

    Where:

    • Wh max is the maximum allowable energy that can be recorded by the watt-hour standard in a fifteen-minute period with the creep switch enabled
    • Volt max is the maximum voltage used for verifying meters
    • Current min is the minimum current used for verifying meters

    Example: Let, volt max = 600 volts, current min = 0.1 amps

    Then Whmax =  (0.001 × (600) × (0.10) × 15) ÷ 60

    = 0.015 watt hours

  11. Complete the worksheets related to this procedure.
6.4.1.3 Remarks

If the watt-hour standard registers less than 10% of the allowable energy after 5 minutes, the creep switch will be deemed to have met the requirements of EL-ENG-12-01.

6.4.2 Indicating instruments (EL-ENG-12-01, s. 6.4.2)

6.4.2.1 Guidelines

The indicating instruments are required to indicate all voltages, currents, phase angles and loads necessary to verify all the meter types to be verified on the console. This test is conducted by measuring voltages, currents, phase angles and loads at a MUT position with a standard indicating those values and comparing the results with the results of the calibration console indicating instruments. The console shall be equipped with a voltmeter, ammeter, and phase angle or power factor indicating meter. Consoles used for watt or watt-hour testing shall be equipped with a watt meter. Consoles used for VA or VA-hour testing shall be equipped with a volt ampere power meter (rms or average as required). Consoles used for Var meter testing shall be equipped with a Var power meter. Applying a multiplier to the indicating instruments in order to obtain the true value is permitted. If a console is equipped with two instruments that can measure the same quantity, both instruments shall be tested for precision within their maximum range. Requirements for power indicating instruments may be satisfied by calibration console reference meters as stated in section 6.4.3.3 of EL-ENG-12-01. All indicating instruments should be readily accessible and easily viewed by the operator while setting loads. If a power standard is used as an indicating instrument for monitoring power, its accuracy as an indicating instrument is sufficiently evaluated by assessments carried out under section 7.8 of EL-ENG-12-01.

6.4.2.2 General procedure and guidelines for indicating instrument assessment
  1. Record test results with two digits of resolution after the decimal point unless it is not practical (e.g. power meters may be assessed by determining the acceptable range provided by the tolerance and indicating either a pass or fail on the worksheets).
  2. Enable regulators as required to obtain stable readings.
  3. When testing manual or semi-automatic consoles, set the loads using the normal operating procedure for the console. With fully automatic consoles, input the required load values and the console sets the load automatically.
  4. Verify all consoles for volts, amps, and the phase angle. Tests for power meters are required for each power quantity used for verifying meters on the console, unless power indicating instruments are calibrated as reference meters as well.
  5. Calculate target quantities before carrying out the assessment using the information provided in the sections below and record the target values on the worksheets.

Note: A list of target test points for this procedure is provided pursuant to section 6.4.3.3, Tables 2 to 5 of EL-ENG-12-01. The values identified in the tables are sufficient for establishing compliance with indicating instrument requirements for meter verification test points that fall within the identified values. Only values applicable to the meters that are verified on the console are required to be assessed. Any target test points found in the tables of EL-ENG-12-01 that exceed the range of test points used for verifying meters are not required to be evaluated. Tolerances for indicating instruments may be found in section 6.4.3.3, Table 1 of EL-ENG-12-01.

6.4.2.3 Procedure for the assessment of voltmeters and ammeters
  1. Plug the test socket adapter in a MUT position.
  2. Using two leads, connect the voltage input of a standard to the test socket binding posts.
  3. In the same MUT, connect the current circuit of the standard in series with the test socket.
  4. Install jumpers or meters of appropriate current rating in the remaining MUT positions.
  5. Select "volts (rms)" or "amps (rms)" on the console and the standard.
  6. Energize the voltage or current circuit of the console.
  7. Set the target test voltage or test current on the console pursuant to section 6.4.3.3, Table 2 of EL-ENG-12-01.
  8. Read the true voltage or current value on the standard and console indicating instrument and record the readings on the voltmeter or ammeter calibration worksheet.
  9. Repeat for all required test voltages and currents.
6.4.2.4 Power indicating instrument assessment
  1. Select "watt", "Var", "VA(rms)" or "VA(average)" on the console and the standard.
  2. Energize current and voltage circuits.
  3. Set the test current, voltage, phase angle and target power on the console pursuant to section 6.4.3.3, Tables 3 and 4 of EL-ENG-12-01.
  4. Read the true power on the standard and console indicating instrument and record the readings on the "watt", "Var", "VA(rms)" or "VA(average)" meter calibration worksheet.
  5. Repeat steps (3) and (4) for all required loads.
6.4.2.5 Phase angle and power factor meter assessment
  1. Plug the test socket adapter in a MUT position and connect the current coils of two standards in series with the test socket or a standard that measures the phase angle directly.
  2. Connect the voltage coils of the two standards in parallel with the voltage output at the test socket.
  3. Use coaxial cables to connect the input resets of the two standards in parallel with a T-adapter and connect the stop/start switch (see formulae in 6.4.2.7).
  4. When testing with current lagging by 0 degrees (1.0 Pf), −30 degrees (0.866 Pf), or −60 degrees (0.50 Pf), set the display of one standard to Wh and the other to VAh. The other option is to use a standard that measures the phase angle or power factor directly and compare the standard measurement of the phase angle or power factor with the indicating instrument being assessed.
  5. Energize current and voltage circuits.
  6. Set the first current, voltage, phase angle or power factor, and power meter target as determined pursuant to section 6.4.3.3, Table 5 of EL-ENG-12-01.
  7. Start both standards and let them register for 10 seconds.
  8. Read the standards displays and the phase angle meter or the power factor indicator of the console.
  9. To calculate the angle, refer to section 6.4.2.7 and record the results on the phase angle or power factor worksheet.
  10. Repeat steps (7) and (8) for all required phase angles or power factors as determined pursuant to section 6.4.3.3, Table 5 of EL-ENG-12-01.
6.4.2.6 Remarks
  1. The preferred location for connecting the voltage leads is at the test socket voltage binding posts. An alternative is to connect the voltage leads to the voltage binding posts of this position on the console panel. Late model consoles may not have voltage binding posts on the console panel, in which case, a test socket with voltage binding posts must be used.
  2. If the test current exceeds the maximum rated input of a single current standard current coil, the input and output current leads can be connected to two or three paralleled input current coils on the standard (e.g. Radian standards). This allows the standard to measure higher currents without the use of external current transformers.
6.4.2.7 Formulae
  1. Calculate the true phase angle from the readings of the two standards with current lagging voltage by 0 degrees (1.0 Pf), −30 degrees (0.866 Pf), or −60 degrees (0.5 Pf) as follows:
    PhaseAngle = Inverse cos (Wh÷VAh)
  2. Examples of phase angle error calculations:

    Example 1: The target phase angle is 60 degrees

    The Pf indicated on the console is 0.49242

    The calculated (true) Pf using reference standards is 0.49546

    %error = ([Indicated−True]÷True) × 100

    %error = ([(cos A) − (cos B)]÷(cos B)) × 100

    %error = ((0.49242 − 0.49546) ÷ 049546) × 100

    = 0.61%

    Example 2: The target phase angle is 60 degrees

    The phase angle indicated on the console is 60.5 degrees

    The calculated (true) phase angle using reference standards is 60.3 degrees

    Angular error = Indicated − True = 60.5 degrees − 60.3 degrees = 0.2 degrees

6.4.3 Accuracy and repeatability of load settings (EL-ENG-12-01, s. 6.4.4)

6.4.3.1 Guidelines

In order to ensure consistency in electricity meter testing, fully automatic and semi-automatic consoles are required to be tested to ensure they can set and reset currents, voltages, phase angles and loads with accuracy and repeatability within one minute of any change in setting. In this procedure, the console is energized to the test load determined pursuant to section 7.2.2 of EL-ENG-12-01. The voltage, current, power and phase angle are measured at a MUT position and compared to the values set for the console. The console is then set and reset without adjusting the load three successive times and the resulting voltage, current, power and phase angle are measured after each resetting of the load.

6.4.3.2 Procedure for the assessment of the accuracy and repeatability of load settings
  1. Place shorting bars in all but one of the MUT positions.
  2. Place the test socket in one MUT position.
  3. Using the appropriate leads, connect the Radian standards in series with the "Left" current circuit of the test console and in parallel with the "Left" voltage circuit of the test console. Ensure the other two current circuits are shorted at the test socket.
  4. Energize the console to the test load determined pursuant to section 7.2.2 of EL-ENG-12-01.
  5. For semi-automatic consoles, manually adjust variacs or rheostats to obtain as close as possible the expected voltage, current, power and phase angle.
  6. For fully automatic consoles, record the resulting voltage, current, power and phase angle in the Repeatability of Load Setting section of the worksheets. The measured values should not differ from the expected results by more than the tolerances specified in section 6.4.2.2, Table 1 of EL-ENG-12-01.
  7. De-energize the console according to the normal operating procedure for the console (i.e. activate the "stop" or "reset" switch).
  8. Re-energize the console according to the normal operating procedure for the console (i.e. activate the "start" or "test" switch). Record the resulting voltage, current, power and phase angle on the Repeatability of Load Setting section of the worksheets.
  9. Repeat steps (7) and (8) two more times.
  10. All measured values should be within the tolerances specified in section 6.4.3.3, Table 1 of EL-ENG-12-01.

Note: Do not make any manual adjustments while following steps (7) to (10).

6.4.3.3 Remarks

Calibration consoles that do not meet the requirements of EL-ENG-12-01 for this test may be certified for use as manual consoles only. Manual consoles are also required to be able to set voltages, currents, and phase angles within the tolerances specified in section 6.4.3.3, Table 1 of EL-ENG-12-01.

6.4.4 Calibration console energy and demand reference meters (EL-ENG-12-01, ss. 6.4.5 to 6.4.7)

6.4.4.1 Guidelines
  1. In order to reduce uncertainties of the energy (i.e. watt-hours, var-hours, volt ampere hours, etc.) and demand (i.e. watt, VA or Var) meters being verified on a console, highly accurate and precise reference meters are necessary.
  2. The limits prescribed for energy and demand reference meters must comply with sections 6.4.6 and 6.4.7 of EL-ENG-12-01.
  3. Compliance with EL-ENG-12-01 can be met through calibration of the console by counting pulses ten times greater than pulses used for verifying meters.
  4. Calibration consoles that automatically calculate and display errors are required to display the errors to a resolution of two significant digits to the right of the decimal point when the console is being calibrated.
  5. A demand reference meter is required for verification of electromechanical demand meters and electronic block interval meters that cannot be verified using energy test methods. The demand reference meter can be a high accuracy power meter. This demand/power meter is required to display a minimum number of significant digits as prescribed in section 6.4.7.1 of EL-ENG-12-01.
  6. It is recommended that all available information relating to the reference meter types that will be verified on the console be reviewed in order to determine their correct use.
  7. A demand reference value used for calibration of the console or assessment of meters shall be established by averaging at least three power readings taken periodically during the calibration of the console, as well as when using the console for demand verification.
6.4.4.2 Procedure
  1. Review the electrical quantities used for verifying meters and determine the electrical quantities energy reference meters and demand reference meters will be required to measure when using the console.
  2. Enter the information in the required worksheet and indicate the type of energy reference meters required (e.g. watt-hour, volt ampere-hour (rms), volt ampere-hour (average), Var-hour or other).
  3. Enter the information in the required worksheet and indicate the type of demand reference meters required (e.g. watt, volt ampere (rms), volt ampere (average), Var or other).

    Note: If the console is used for testing block interval demand meters only and a control circuit is used for testing demand meters, demand reference meters are not required as per section 6.4.7 of EL-ENG-12-01.

  4. Enter in the worksheet the pulse output value for the energy reference meters and indicate if the requirements of EL-ENG-12-01 are met.
  5. Enter in the worksheet the number of significant digits of the test errors displayed by the console if the console automatically displays test errors. If the console does not automatically display the MUT errors, make a note to that effect on the worksheet.
  6. Enter in the worksheet the significant digits of the demand reference meters and indicate if the requirements of EL-ENG-12-01 are met.
  7. Enter in the worksheets the number of MUT positions equipped with the control circuits for verifying demand meters using energy test methods.
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