PSC 113.0914
PSC 113.0914 Testing of polyphase electromechanical and completely solid state electronic meters used with instrument transformers at fixed periodic intervals. In this section, “meter" or “meters" may refer to metering system(s).
PSC 113.0914(1)
(1) Polyphase meters used with instrument transformers, together with associated equipment such as demand equipment, pulsing devices, phase-shifting transformers, control devices, etc., shall be tested on the customer's premises, a central testing facility or in a mobile test facility, except for pars.
(a) and
(d), for accuracy at unity and 50% power factor under the following circumstances.
PSC 113.0914(1)(a)
(a) Before being placed in service. For new meters given a prior test by the manufacturer, the manufacturer's certified test results may be substituted for this requirement.
PSC 113.0914(1)(e)
(e) Within a period of 4 months before or 4 months after 2 years of service for non-magnetic-bearing electromechanical meters, 4 years of service for electromechanical magnetic-bearing surge-proof meters and 6 years of service for completely solid state electronic meters with electronic registers capable of down-loading voltage and current monitoring readings from the instrument transformers to digital meter reading devices at meter reading intervals. Exception: Electronic (solid state) meters may be tested instead in accordance with the plan outlined in s.
PSC 113.0921.
PSC 113.0914(2)
(2) A stator balance test shall be performed on all new meters before being placed in service.
PSC 113.0914(3)
(3) Meters with electronic programmable registers may be shop tested on a periodic basis.
PSC 113.0914 History
History: Cr.
Register, July, 2000, No. 535, eff. 8-1-00;
CR 02-027: am. (1) (intro.) and (a),
Register December 2002 No. 564, eff. 1-1-03.
PSC 113.0915
PSC 113.0915 Testing of metering installations utilizing pulse devices. PSC 113.0915(1)(1)
Metering installations utilizing pulse initiators and pulse recorders shall be checked for accuracy each billing period by comparing the recorded pulse count against the registration of the corresponding meter. When the results are not in agreement within the accuracy limits of s.
PSC 113.0812 (2) the pulse devices shall be promptly tested and adjusted to required accuracy or replaced.
PSC 113.0915(2)
(2) Pulse devices shall be tested before use and as part of the complete metering installation whenever the associated watthour meter is tested.
PSC 113.0915 History
History: Cr.
Register, July, 2000, No. 535, eff. 8-1-00.
PSC 113.0916
PSC 113.0916 Testing of instrument transformers. PSC 113.0916(1)(1)
No instrument transformer shall be placed in service, or allowed to remain in service, if it shows evidence of physical damage, discolored terminals due to overload, change in texture or resiliency of insulation, or arc tracking on the insulation or bushings.
PSC 113.0916(2)
(2) Instrument transformers of all utilities shall be tested for voltage withstand by the manufacturer, the utility, or a laboratory approved for such test by the commission before being placed in service. Each instrument transformer that has been removed from service shall be tested for voltage withstand prior to reinstallation if the reason for removal or physical appearance, gives cause to doubt its reliability. The utility shall maintain a record of all such tests.
PSC 113.0916(3)
(3) Instrument transformers of class A privately-owned utilities shall be tested at the utility meter shop or the manufacturers' certified test reports may be used to determine accuracy (ratio correction factor and phase angle):
PSC 113.0916(3)(c)
(c) When there is evidence from outward appearance or performance to suspect inaccuracy.
PSC 113.0916(3)(d)
(d) The manufacturer's calibration results may be acceptable on all new voltage transformers rated above 15,000 volts. Removal tests of these transformers may also be omitted except in those cases where there is reason to suspect that a transformer malfunction has occurred.
PSC 113.0916(4)
(4) Instrument transformers of other than class A private-owned utilities shall be tested at the utilities meter shop, the manufacturer's laboratory or a laboratory approved by the commission for accuracy (ratio correction factor and phase angle):
PSC 113.0916(4)(b)
(b) When there is evidence from outward appearance or performance to suspect inaccuracy.
PSC 113.0916(5)
(5) Instrument transformers in service shall be given an approved check (such as the variable burden method in the case of current transformers or a field check of the secondary voltage with a good quality voltmeter in the case of voltage transformers) made in conjunction with each field test of the associated watthour meter. When such check provides evidence that the instrument transformer may be inaccurate, that instrument transformer shall be tested for accuracy.
PSC 113.0916 History
History: Cr.
Register, July, 2000, No. 535, eff. 8-1-00.
PSC 113.0917
PSC 113.0917 Phase-shifting transformers and loss compensators. PSC 113.0917(1)(1)
For phase-shifting transformers in service, all terminal connections shall be in such condition as to provide good electrical contact and the terminal designations shall be clearly visible. Where there is evidence of physical damage or evidence of thermal overload the unit shall be replaced.
PSC 113.0917(2)
(2) Phase-shifting transformers shall be tested on the same schedule and at the same time as the meters with which they are associated. The test shall consist of a single-phase test to be performed as follows: With the approximate rated voltage applied to the input terminals and no burdens connected to the tap terminals all tap voltages, converted to percentage of input voltage, shall agree within plus or minus 2.0% of the theoretical values given in the manufacturer's published data.
PSC 113.0917(3)
(3) In addition, all units shall be tested before use and when returned to the utility's meter laboratory. For these tests the output-voltage values in terms of percentage of input voltage and under the conditions of sub.
(2) immediately above shall agree within plus or minus 1.0%.
PSC 113.0917(4)
(4) For transformer-loss compensators in service all terminal connections shall be in such condition as to provide good electrical contact and the terminal designations shall be clearly visible. Where there is evidence of physical damage to the component parts, their adjustments, or to the internal wiring or evidence of thermal overload on the insulation, resistors, terminals, etc., the affected parts shall be replaced or the entire transformer-loss compensator replaced.
PSC 113.0917(5)
(5) Transformer-loss compensators shall be tested on the same schedule and at the same time as the meters with which they are associated.
PSC 113.0917(6)
(6) The tests shall be made at the normal service test points of the meter. Performance deviations from desired performance shall not exceed plus or minus 0.3%.
PSC 113.0917 History
History: Cr.
Register, July, 2000, No. 535, eff. 8-1-00.
PSC 113.0918
PSC 113.0918 Adoption of standard by reference. PSC 113.0918(1)(1)
Adoption of standard. Military Standard 414 (Mil-STD-414) dated June 11, 1957, is hereby incorporated by reference into ch.
PSC 113 in part consisting of the cover page and pages 1, 2, 3, 4, 41, 42, 43, 45, 47, 48, 49, 50, 51 and 110. This published standard is entitled “Sampling Procedures and Tables for Inspection by Variables for Percent Defective" and is referenced in ss.
PSC 113.0920 and
113.0921 herein for application of these rules on maintenance of electric meter accuracy by statistical sample testing methods. Interim amendments to MIL-STD-414 will not be effective in this state until such time as this chapter is revised to reflect such changes.
PSC 113.0918(2)
(2)
Consent to incorporate. Pursuant to s.
227.21, Stats., the attorney general and the legislative reference bureau have consented to the incorporation by reference of MIL-STD-414 in part as designated in sub.
(1). Copies are on file in the offices of the commission, the secretary of state and the legislative reference bureau.
PSC 113.0918(3)
(3)
Availability of standard. Copies of that part of MIL-STD-414 adopted herein may be obtained from the commission. Copies of the entire MIL-STD-414 may be ordered from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.
PSC 113.0918 History
History: Cr.
Register, July, 2000, No. 535, eff. 8-1-00; correction made in (2) under s.
13.92 (4) (b) 6., Stats.,
Register April 2013 No.688.
PSC 113.0919(1)(a)
(a) A utility shall keep a record of a test whenever a unit of metering equipment is tested. The meter test record shall include all of the following:
PSC 113.0919(1)(a)10.
10. A statement as to whether or not the unit of metering equipment “creeps" and in case of creeping, all of the following:
PSC 113.0919(1)(a)10.b.
b. A statement of “as found" and “as left" accuracies sufficiently complete to permit checking of the calculations employed.
PSC 113.0919(1)(a)10.d.
d. A statement of repairs made by the utility, if any, or a notation that the unit was returned to the manufacturer for repairs.
PSC 113.0919(1)(b)
(b) Meter test records and meter history records may be kept as separate records or one record.
PSC 113.0919 Note
Note: Meter test records need not be separately retained from meter history records provided that the meter test records are incorporated into the meter history records.
PSC 113.0919(2)(a)(a) Each utility shall keep a history record for each unit of metering equipment showing all of the following:
PSC 113.0919(2)(a)7.
7. Results of the last “as found" and “as left" tests, unless separate records are kept of each test for each unit.
PSC 113.0919(2)(a)8.
8. Locations where the unit has been installed, with dates of installation and removal.
PSC 113.0919(2)(b)
(b) Meter test records and meter history records may be kept as separate records or one record.
PSC 113.0919(3)
(3)
Statistical sampling summaries. Each utility authorized to test meters under the statistical sample testing plan of s.
PSC 113.0921 shall submit to the commission, by April 15 of the following year, a summary of the statistical sample testing results for the prior calendar year. The summary shall include group and lot numbers; a description of meters in each lot; the number or meters in each lot; the number of meters sample tested in each lot; full load sample mean accuracy (
x), estimated standard deviation (s) and total estimated percent defective (P); light load sample mean accuracy
x , estimated standard deviation (s) and total estimated percent defective (P); projected annual rates of change for
x , s and P at both full and light load analysis points; lots requiring testing and actual
x, s and P data from meters where entire lot tests were required under the program; group and lot numbers; a description of meters in each lot and the number of meters in each lot for the succeeding test year.
PSC 113.0919(4)
(4)
Computerized meter record system. Utilities with more than 5,000 metered customers shall acquire or develop a computerized meter records system and use it for maintaining all required meter equipment records, scheduling and implementing all required meter testing and analyzing meter accuracy performance. The reporting system and software must be acceptable to the commission.
PSC 113.0919 History
History: Cr.
Register, July, 2000, No. 535, eff. 8-1-00;
CR 13-033: r. and recr. (1), (2), cr. (3) (title), (4) (title)
Register July 2015 No. 715, eff. 8-1-15.
PSC 113.0920
PSC 113.0920 Statistical sample testing plan for new self-contained single phase and 3-wire network meters. The new meter sample testing plan described in subs.
(1) to
(5) may be used for testing new self-contained, single phase and 3-wire network meters without mechanical demand registers or mechanical pulsing devices instead of the new meter test requirements of s.
PSC 113.0911 (1) (a), if the commission authorizes the adoption of the plan by a utility.
PSC 113.0920(1)
(1) Meters, as received from the manufacturer, shall be divided into homogeneous lots by manufacturers and type. The maximum number of meters in any lot may not exceed 1,000 or be less than 96. From each such lot assembled, there shall be drawn a coded sample size specified in Military Standard 414, (MIL-STD-414) dated 11 June 1957, as shown for the various group sizes using Inspection Level IV of Table A-2 on page 4 and a corresponding actual sample size as shown in Table B-3 on page 45. The sample shall be drawn by a random method that ensures that each meter in the lot has an equal chance of being selected.
PSC 113.0920(2)
(2) The test criterion for acceptance or rejection of each lot shall be based on a separate analysis conducted at both the full load and light load test points at unity power factor, as specified in s.
PSC 113.0811 (1) (c), by means of the Standard Deviation Method, Double Specification Limit and with an Acceptable Quality Level (AQL) of 0.25 for the full load accuracy analysis and an AQL of 0.40 for the light load accuracy analysis as shown in Table B-3, MIL-STD-414, page 45. The statistical analysis calculations shall be made following the example outlined on page 43 of MIL-STD-414 with the upper and lower specification limits U and L designated at 101% and 99% respectively.
PSC 113.0920(3)
(3) One non-registering meter may be removed from the sample lot for analysis purposes and replaced with another randomly selected meter. If more than one meter in a sample lot is found not to be registering, the entire lot shall be rejected.
PSC 113.0920(4)
(4) A lot shall be deemed acceptable for installation if the total estimated percent defective (P) is less than the appropriate maximum allowable percent defective (M) as determined from Table B-3 under the procedures of sub.
(2). All meters in an acceptable lot shall be deemed to have met the accuracy requirements of s.
PSC 113.0811 for placement in service without further testing.
PSC 113.0920(5)
(5) A lot shall be considered rejected (not acceptable for installation) if the total estimated percent defective (P) is greater than or equal to the appropriate maximum allowable percent defective (M) as determined from Table B-3 under the procedures of sub.
(2). All meters in a rejected lot shall be tested and adjusted in accordance with the procedures of s.
PSC 113.0811 or replaced with meters meeting these requirements.
PSC 113.0920 History
History: Cr.
Register, July, 2000, No. 535, eff. 8-1-00.
PSC 113.0921
PSC 113.0921 Statistical sample testing plan for in-service, electronic (solid state) meters and electromechanical, self-contained, single phase and 3-wire network meters. PSC 113.0921(1)(1)
The statistical sample testing plan described in pars.
(a) to
(e) may be used for testing electronic (solid state) meters and self-contained, single phase and 3-wire network meters without mechanical demand registers or mechanical pulsing devices in place of the periodic testing requirements of s.
PSC 113.0911 if the commission authorizes the adoption of the plan by a utility.
PSC 113.0921(1)(a)
(a) All extended range, surge proof designed meters shall be divided into homogeneous groups based on meter design features and age. The groups shall be further divided into lot sizes categorized by manufacturer, type, serial number, group size or load duty cycle with lot sizes containing a minimum of 26 meters and a maximum of 110,000 meters. The number of lots or lot composition and size may be changed at the end of the sample testing year to allow for increasing or decreasing analysis of accuracy testing requirements on any segment of meters in any lot.
PSC 113.0921(1)(b)
(b) Annually, from each of the assembled lots, a coded sample size specified in Table A-2, Inspection Level IV, page 4 of Military Standard 414, (MIL-STD-414) dated 11 June 1957 and a corresponding actual sample size as shown on Table B-3 page 45, (MIL-STD-414), shall be randomly selected for testing and analysis purposes. Each meter in the lot sample shall be provided with a full load and light load test for accuracy at unity power factor, as specified under s.
PSC 113.0811 (1) (c). A separate statistical analysis shall be performed on each lot sample at each of these 2 load ranges. All meters not registering at either full or light load test points shall be removed from the lot sample and replaced with a different randomly selected meter and not more than two lot sample meters operating outside of the accuracy bandwidth of 95% to 105% at either test load point shall be removed and replaced from the lot sample.
PSC 113.0921(1)(c)
(c) The statistical analysis calculations for both the full and light load accuracy results from the sample lot tests shall be made following the example outlined on page 43 of MIL-STD-414 with the upper and lower specification limits, U and L designated at 102% and 98% respectively. The test criterion for acceptance or rejection of each lot shall be by the Standard Deviation Method, Double Specification Limit with an Acceptable Quality Level (AQL) of 1.00 for the full load analysis and 4.00 for the light load analysis (both normal inspection) as shown on Table B-3, page 45 of MIL-STD-414.
PSC 113.0921(1)(d)
(d) A lot shall be deemed acceptable for continued use if the total estimated percent defective (P) is less than the appropriate maximum allowable percent defective (M) as determined from Table B-3, page 45 of MIL-STD-414, following the procedure of par.
(c) for both the full load and light load analysis test points at the respective designated Acceptable Quality Levels. All of the meters in the accepted lot may be retained in use without further accuracy adjustments and will be concluded to have the accuracy characteristics specified in s.
PSC 113.0811 (1) (c). Meters in the sample lot may be adjusted for acceptable accuracy as required or maintained as necessary and returned to the lot.
PSC 113.0921(1)(e)
(e) A lot shall be deemed unacceptable and rejected for continued use if the total estimated percent defective (P) is greater than or equal to the appropriate maximum allowable percent defective (M) as determined from Table B-3, page 45 MIL-STD-414, following the procedure of par.
(c) for both the full load and light load analysis test points at the respective designated Acceptable Quality Levels on any 2 annual sample testing analysis years within a five-year period for the lot or any meters in the lot. All meters in a rejected lot shall be provided with an appropriate test within a period of 48 months from the date of completion of the sample analysis and all the meters tested in the rejected lot shall be adjusted to the accuracies specified in s.
PSC 113.0811 (1) (c). All meters in a rejected lot that will not be returned to service shall be removed within 48 months from the date of completion of the sample analysis. These meters may be retired without a test. Annual statistical sample testing shall be terminated during the period when all of the meters in a rejected lot are being provided with a test and accuracy adjustment.
PSC 113.0921(1)(f)
(f) All meters in any lot may be tested and adjusted for proper accuracy over a 48-month period at the discretion of the utility without a sample analysis determination specifying the lot test is necessary.
