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HomeMy WebLinkAbout1996-42 Renewal Resource PolicyRESOLUTION NO. 96. ~7~ ~' A RESOLUTION ESTABLISHING A RENEWAL RESOURCE PURCHASE POLICY FOR THE CITY OF ASHLAND. THE CITY OF ASHLAND RESOLVES AS. FOLLOWS: SECTION 1. The City of Ashland encourages citizens and businesses: To invest in renewable electric energy generations systems, and For those who generate electricity, to remain on the electric grid to use it as a backup supply. This policy is designed to provide adequate incentives to encourage renewable generation while remaining on the city's electric grid. SECTION 2. The City of Ashland will purchase solar and wind generated electricity subject to the following conditions: All systems will be installed so as to comply with "Small Scale Solar or Wind Generation Standards for Parallel Operating Reliability" included as Attachment A to this resolution. All systems may utilize a single electric meter, supplied by the City of Ashland, which moves in both directions. Power used from the City moves the meter forward, power generated by the solar or wind system moves the meter backward. Residential and commercial customers are covered by this policy. The first 1000 excess kilowatt-hours (kWh) generated each month by citizen or business will be purchased at the following rate: 1.25 times highest block for residential rate. All additional kWh's produced each month will be purchased at the City's then current wholesale power rate. This policy will be reviewed within one year of the installation of any generation system taking advantage of this policy. This resolution was read by title only in accordance with Ashland Municipal Code Barbara Christensen, City Recorder SIGNED and APPROVED this ,,~ Catherine M. Golden, Mayor , Paul Nolte, City Attorney PAGE 1 - RESOLUTION ATTACHMI~NT A SMALL SCALE SOLAR OR WIND GENERATION STANDARDS FOR PARALLEL OPERATING RELIABILITY 100 kw OR LESS, 660 VOLTS OR LESS A RENEWABLE ENERGY SOURCE The City of Ashland is encouraging the installation of small photovoltaic and wind generators and wishes to interconnect with, and buy from, qualifying facilities. Photovoltaic and wind generators are one method of accomplishing this generation of power by private individuals. This guideline is concerned primarily with the technical engineering aspects of interconnection with a small photovoltaic and wind generator. There are two possible photovoltaic and wind systems which may be interconnected electrically to Ashland's system. These are: The line-commutated inverter The self-commutated inverter There are certain electrical concerns which Ashland has for its customers and its workmen which fall into the following categories. All inter-connection requirements by Ashland are to alleviate these possible problems. Waveform harmonic distortion System operating voltage Voltage flicker Power factor System and producer protection Safety WAVEFORM HARMONIC DISTORTION The main concern with waveform harmonic distortion is with residential applications of D.C. generation sources incorporating inexpensive line commutated inverters. Small Scale Solar or Wind Generation - page I of 5 Excess harmonic distortion can damage utility equipment, such as capacitors, cause overheating of motors and other customer equipment, and cause radio-TV interference. Unfortunately, National Standards for allowable harmonic distortion are not available at this time. Until such standards are developed, Ashland's policy will be not to allow troublesome harmonics and to disconnect from Ashland's distribution system with lociable disconnect, any generator which generates harmonics adversely affecting Ashland's equipment or service to other customers. SYSTEM OPERATING VOLTAGE The on-site generator must be so rated and designed to operate within the normal line voltage variations on Ashland's Distribution System. Unless different limits are established by State Regulatory Authorities, the range of steady-state voltage variations at the point of interconnection shall be in accordance with those maximum and minimum limits established in ANSI C84.1-1977. For the general case these limits will be + 5% of the nominal voltages. POWER FACTOR Line commutated synchronous inverters require VAR supply from the utility system. Power factor correction for a line-commutated synchronous inverter could be accomplished by the addition of capacitors by the Producer. It is difficult to match the correct mount of capacitance to the generation as the best power factor will occur at or near the inverter rated capacity with the worst situation occurring when the inverter is idling or unloaded. If VAR$ are supplied from a non-utility source, the possibility of generator self-excitation increases which creates a possible safety problem. Because of the aforementioned reasons, Ashland will supply all VARS for photovoltaic and wind generators from its system. SYSTEM AND PRODUCER PROTECTION Normal operation of distribution system protective devices my adversely affect the on-site generator. When a fanit is detected on the distribution feeder, the substation breaker opens thereby interrupting for a very brief instant the power flow from the substation out to the londs. The feeder is then re-energized by the first closing operation on the assumption that the fanit was self-cleaxing. If the fault condition persists, the power flow will be interrupted again by a second opening of the station breaker. This time the interruption will be for a longer period of time followed by a second and third closing operation. If still faulted, the breakex will lock open. The effect of this time dehy/recloser cycle upon the on- site generator must be considered in each case. The operation of protective devices on Ashland's system can result in unbalance in the Producer's generator. Producer protection may be provided by following good electrical design practices. The Producer shall provide an automatic load break disconnecting device which will be used in conjunction with relaying devices to protect equipment in case of fault conditions. The Producer shall be required to provide an overcurrent device and other devices to adequately sense electrical variations which my be used to actuate the automatic load break disconnecting device. SAFETY Ashland is vitally concerned about one problem associated with Producer-owned generation. This problem is feedback from a Producer's generator into de-energized conductors and equipment. For example, while working on equipment in an assumed de- energized section of a distribution system, uncontrolled generators, such as those owned by Producers, couid create a hazardous condition in the work area exposing workers to electrical sheck. Company work rules incinding the installation of shorts and grounds on de-energized circuits shall be adhered to. GENERAL REQUIREMENTS FOR SINGLE & THREE-PHASE INSTALLATIONS Any harmonic distortions attributable to the operation of generation equipment that results in objectionable service to other customers shall be remedied by the Producer. If such remedies are not provided, the generation may be subject to disconnection from the utilities lines. Installation shah be in compliance with current editions of the national Electrical Code, the National Electrical Safety Code, or applicable state code. A lockable main disconnect switch which shall provide a visible open circuit in the off position shall be provided to isolate Producer's generation from Ashiand's system. Producer's system, including interconnection equipment, shall meet requirements of and be inspected and approved by the local or state authority having jurisdiction. Producer shall provide a circuit breaker or similar switching device which is designed to automatically disconnect the Producer's generator from Ashland's system on a predetermined setting and shall have an interrupting rating adequate for load current and fault current at the location. ~m~eS~ar~WhdGems~~~ge3o~S 6. Producer shah provide an overcurvet sensing device in each phase. The system shah be designed to automatically disconnect when Asldand's service is interrupted. Ashland shall establish a dedicated voltage transformation, with ground source for the Producer's generation and load. All protective devices employed shall be subject to Ashland's review for adequacy and shah be subject to Ashland's requirements for value setting and periodic testing. 10. Producer shall provide the following items prior to actual interconnection. A one-line function schematic diagram of the photovoltaic and wind generation electrical system. b. A plot plan interconnection diagram. A written document which discusses normal and failure mode operation of the photovoltaic and wind generation electrical system. A table of photovoltaic and wind generation electrical system characteristics consisting of: 1) 2) 3) 4) 5) Rated and maximum A-C output, real power and kVA. Rated A-C line voltage. Rated A-C line current. Power factor and VAR characteristics at 25, :50, 75 and 100% of rated real power output. Voltage/current harmonic characteristics at 25, 50, 75 and 100% of rated real power output. Maximum inrush currents dram during start-up or normal operation. C. ADDITIONAL REOI, IHIEMENTS - SINGLE AND THREE PHASE INSTALLATIONS The following additional requirements rapresent the best protection criteria available at the time of this writing. Any new criteria which may be published in the future will be incoq~orated in following revisions. Ashland may relax the foliowing additional requirements if conditions of size, other protection methods, or other reasons dictate the need. Any relax- ation of additional requirements shall be done with the full consent of the Director or Electric Utility on an individual basis. 1. Photovoltaic and wind generation with line commutated inverter: must have overfrequency relay must have underfrequency relay must have overvoltage relay must have undervoltage relay 2. Photovoltaic and wind generation with self-commutated inverter: must have overfrequency relay must have underfrequency relay must have overvoltage relay must have undervoltage relay facilities shall include equipment necessary to automatically establish and maintain synchronism with Ashland's electrical supply