Iowa Admin. Code r. 199-20.7 - Standards of quality of service
(1)
Standard frequency. The standard frequency for alternating current distribution
systems shall be 60 cycles per second. The frequency shall be maintained within
limits which will permit the satisfactory operation of customer's clocks
connected to the system.
(2)
Voltage limits retail. Each utility supplying electric service to ultimate
customers shall provide service voltages in conformance with the standard at
20.5(2)"d. "
(3)
Voltage balance. Where three-phase service is provided the utility shall
exercise reasonable care to assure that the phase voltages are in balance. In
no case shall the ratio of maximum voltage deviation from average to average
voltage exceed .02.
(4) Voltage
limits, service for resale. The nominal voltage shall be as mutually agreed
upon by the parties concerned. The allowable variation shall not exceed 7.5
percent above or below the agreed-upon nominal voltage without the express
approval of the board.
(5)
Exceptions to voltage requirements. Voltage outside the limits specified will
not be considered a violation when the variations:
a. Arise from the action of the
elements.
b. Are infrequent
fluctuations not exceeding five minutes, duration.
c. Arise from service
interruptions.
d. Arise from
temporary separation of parts of the system from the main system.
e. Are from causes beyond the control of the
utility.
f. Do not exceed 10
percent above or below the standard nominal voltage, and service is at a
distribution line or transmission line voltage with the retail customer
providing voltage regulators.
(6) Voltage surveys and records. Voltage
measurements shall be made at the customer's entrance terminals. For
single-phase service the measurement shall be made between the grounded
conductor and the ungrounded conductors. For three-phase service the
measurement shall be made between the phase wires.
(7) Each utility shall make a sufficient
number of voltage measurements in order to determine if voltages are in
compliance with the requirements as stated in 20.7(2), 20.7(3), and 20.7(4).
All records obtained under this subrule shall be retained by the utility for at
least two years and shall be available for inspection by the board's
representatives. Notations on each chart shall indicate the following:
a. The location where the voltage was
taken.
b. The time and date of the
test.
c. The results of the
comparison with a working standard indicating voltmeter.
(8) Equipment for voltage measurements.
a.
Secondary standard indicating
voltmeter. Each utility shall have available at least one indicating
voltmeter maintained with error no greater than 0.25 percent of full
scale.
b.
Working standard
indicating voltmeters. Each utility shall have at least two indicating
voltmeters maintained so as to have as-left errors of no greater than 1 percent
of full scale.
c.
Recording
voltmeters. Each utility must have readily available at least two
portable recording voltmeters with a rated accuracy of 1 percent of full
scale.
(9) Rescinded IAB
12/11/91, effective 1/15/92.
(10)
Extreme care must be exercised in the handling of standards and instruments to
assure that their accuracy is not disturbed. Each standard shall be accompanied
at all times by a certificate or calibration card, duly signed and dated, on
which are recorded the corrections required to compensate for errors found at
the customary test points at the time of the last previous test.
(11) Planned interruptions shall be made at a
time that will not cause unreasonable inconvenience to customers, and
interruptions planned for longer than one hour shall be preceded by adequate
notice to those who will be affected.
(12) Power quality monitoring. Each utility
shall investigate power quality complaints from its customers and determine if
the cause of the problem is on the utility's systems. In addressing these
problems, each utility shall implement to the extent reasonably practical the
practices outlined in the standard given at 20.5(2)"f. "
(13) Harmonics. A harmonic is a
sinusoidal component of the 60 cycles per second fundamental wave having a
frequency that is an integral multiple of the fundamental frequency. When
excessive harmonics problems arise, each electric utility shall investigate and
take actions to rectify the problem. In addressing harmonics problems, the
utility and the customer shall implement to the extent practicable and in
conformance with prudent operation the practices outlined in the standard at
20.5(2)"g. "
This rule is intended to implement Iowa Code sections 476.2 and 476.8.
Notes
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