Current through Register Vol. XLI, No. 50, December 13, 2024
Section 150-3-7 - Standards of Quality of Service7.1. Standard voltage -- Each utility shall adopt a standard nominal voltage or standard nominal voltages, as may be required by the design of its distribution system for its entire constant voltage service, or for each of the several districts into which the systems may be divided, which standard voltages shall be filed with the Commission.7.2. Voltage regulation. 7.2.1. Residential or lighting -- The voltage level at the customer's service entrance equipment for a residential customer or a customer using service primarily for lighting shall be maintained between 112 volts and 127 volts on a 120 volt base.7.2.2. Power. 7.2.2.a. For service rendered under a power contract or primarily for power purposes the voltage variation shall not exceed ten percent (10%) above or ten percent (10%) below standard voltage at any time the service is regularly furnished.7.2.2.b. Service under a power contract means service furnished principally for industrial purposes. Where a limited amount of lighting (twenty percent (20%)) or less by connected load) is permitted to be connected under these contracts, the entire load shall be considered power as far as voltage variation is concerned.7.2.3. Measurement point. 7.2.3.a. The point where voltage measurements are to be made shall be at the customer's service entrance equipment or at the lamps in the case of multiple street lighting.7.2.3.b. The utility will be responsible for the voltage delivered at this point if the utility furnishes the service entrance conductors, carries them in its fixed capital account or accepts the responsibility of ownership.7.2.3.c. If the customer furnishes and maintains the service entrance conductors, proper allowance may be made on any voltage tests if the conductors are not of reasonable size.7.2.4. Combined light and power -- By contracts contemplating an appreciable consumption or demand for lighting purposes is meant such service as street lighting, residential, commercial lighting, and combined lighting and power. If service is furnished at primary voltage to an ultimate customer under a combined lighting and power contract it is expected that the utility will limit the voltage fluctuation to give proper secondary voltage within the limits prescribed, assuming proper equipment is supplied by the customer.7.2.5. Voltage variation -- The variation in voltage allowed in all parts of the rule except Rule 7.2.6. means the gradual change in voltage as a result of normal changes in load.7.2.6. Flicker -- Flicker is frequent and sudden changes in voltage occurring in one (1) second or less and exceeding three percent (3%) of the standard voltage. While occasional voltage fluctuations in excess of that listed above must be expected in the normal operation of a system, continuous flicker will be construed as below standard service, unless such variations are caused by the customer's own equipment.7.2.7. Emergency service -- A greater variation in voltage than specified in this rule will be allowed for emergency service, but standby service must comply with the rules unless covered by a special contract.7.3. Voltage surveys. 7.3.1. Instruments -- Each utility shall provide itself with one (1) or more portable indicating voltmeters, and every utility serving more than seven hundred fifty (750) customers shall have available one or more recording (curve-drawing) voltmeters of type and capacity suited to the voltage supplied.7.3.2. Every utility shall make a sufficient number of voltage surveys to indicate the service furnished from each center of distribution, and to satisfy the Commission of its compliance with the voltage requirements, and those having curve-drawing voltmeters shall keep at least one (1) of those instruments in continuous service at some representative point on its system. This last requirement will be considered to be satisfied in the case of utilities purchasing all of their power requirements if a recording voltmeter is continuously in service at the nearest attended substation of the supplier of the energy. All records shall be available for inspection by the utility's customers, and the Commission or its representative, for a period of at least one (1) year.7.3.3. Each recording voltmeter shall be checked with an indicating voltmeter when it is placed in operation or when it is removed.7.3.4. Notations shall be made on each chart to indicate when registration began (time and date) and when the chart was removed, as well as to indicate the point where the chart was checked with the indicating voltmeter.7.4. Standard frequency -- Each utility supplying alternating current in its distribution system or systems shall use a standard frequency of sixty (60) hertz. This frequency shall be maintained within a band limited by a variation of two percent (2%) below and two percent (2%) above the standard. Should a utility desire to use any frequency other than the "Standard" listed, it may appeal to the Commission for permission to use the frequency desired upon its own distribution system.7.5. Inductive coordination. 7.5.1. All supply and signal circuits with their associated apparatus should be constructed, operated and maintained in conformity with generally accepted coordinated methods with due regard to prevention of interference with the rendering of either service by adequately limiting in the most convenient and economical manner those characteristics of supply circuits which determine the character and intensity of the inductive field, or those characteristics of signal circuits which determine the extent to which the service they are designed to render is affected by a given inductive field, or both.7.5.2. Where such coordinated methods are insufficient in any specific case, special adequate coordinated measures determined by cooperative consideration should be applied to the circuits of either or both kinds, to most conveniently and economically prevent the interference.7.5.3. To facilitate coordination, each party, in advance of any construction or change in the construction or operating conditions of its facilities, should consult with other parties between whose facilities and its own, coordinated measures may be necessary.7.6. Constant current circuits. 7.6.1. Current variation. 7.6.1.a. Constant current circuits supplying street lights shall be so operated that variation in current does not exceed three percent (3%) above nor three percent (3%) below a standard.7.6.1.b. The allowable variation in this rule does not imply that street lighting circuits may be set below or above the circuit rating and maintained at this figure.7.6.2. Service interruptions -- Variations in current in excess of those specified arising from service interruptions caused by the action of the elements and infrequent and unavoidable fluctuations of short duration due to station operation will not be considered a violation of this rule.