This article is intended to provide for the orderly, safe and effective interconnection and parallel operation of distributed generation facilities within the city electric system by customers of the city electric utility.
(Ordinance 12-2022 adopted 10/13/2022)
The city is authorized to enact this article by the Tex. Util. Code Ann. sec. 31.005, which authorizes and encourages electric utilities to establish customer option programs that encourage the reduction of air contaminant emissions including distributed energy generation technology. Also, Tex. Util. Code Ann sec. 39.101(b)(3) entitles all state electric customers access to on-site distributed generation. Finally, Tex. Util. Code Ann sec. 39.916 authorizes electric utilities to establish requirements for and allow the interconnection and parallel operation of distributed renewable generation, and requires the Public Utility Commission of Texas to promulgate rules and regulations for the implementation of interconnection and parallel operation of distributed renewable generation.
(Ordinance 12-2022 adopted 10/13/2022)
As used in this article, the following words and terms shall have the meanings as set forth below:
City manager.
The city manager and/or his/her duly authorized representative.
Commission.
The Public Utility Commission of Texas.
Customer.
A person or entity interconnected to the city electric system for the purpose of receiving or exporting electric power from or to the city electric system.
Distributed generation.
An electrical generating facility located at a customer's point of delivery (point of common coupling) of ten (10) megawatts (MW) or less and connected at a voltage less than sixty (60) kilovolts (kV) which may be connected in parallel operation to the city electric system.
Interconnection.
The physical connection of distributed generation to the utility system in accordance with the requirements of this article so that parallel operation can occur.
Net metering.
A billing mechanism that credits solar energy system owners for the electricity they add to the grid. For example, if a residential customer has a solar power system on their roof, it may generate more electricity than the home uses during the daylight hours.
Networked secondary.
Two (2) or more utility primary distribution feeder sources electrically tied together on the secondary (low voltage) side to form one power source for one (1) or more customers. Networked secondary service is designed to maintain service to the customers even after the loss of one of these primary distribution feeder sources.
Parallel operation.
The operation of distributed generation by a customer while the customer is connected to the city electric system.
Point of interconnection (point of service; point of common coupling).
The point where the electrical conductors of the city's utility system are connected to the customer's conductors and where any transfer of electric power between the customer and the utility system takes place, such as a switchgear near the meter.
Pre-certified equipment.
A specific generating and protective equipment system or systems that have been certified as meeting the applicable parts of this article relating to safety and reliability by an entity approved by the commission.
Stabilized.
The city electric system shall be considered stabilized when, following a disturbance, the system returns to the normal range of voltage and frequency for a duration of two (2) minutes.
(Ordinance 12-2022 adopted 10/13/2022)
This article applies to all persons or entities that desire to interconnect or operate in parallel a distributed generation system within the city electric system.
(Ordinance 12-2022 adopted 10/13/2022)
(a) 
Before a person or entity may interconnect or operate in parallel a distributed generation system within the city electric system, that person or entity must complete and submit an application form provided by the city and execute an agreement with the city, in a form approved by the city council, that establishes the terms and conditions for the interconnection and parallel operation of the distributed generation system.
(b) 
The city council hereby delegates to the city manager the authority to execute agreements with customers for the interconnection and parallel operation of distributed generation within the city electric system in accordance with this article, the Public Utility Commission of Texas rules and regulations, and in accordance with all applicable state and federal laws.
(c) 
Substantial changes to the form and/or intent of the agreement approved by the city council must be approved by the city council before the execution of the revised agreement.
(d) 
The interconnection shall not be energized prior to the execution of the agreement as required herein.
(e) 
The application may be modified from time-to-time by the city manager as is required for appropriate processing of applications.
(Ordinance 12-2022 adopted 10/13/2022)
(a) 
The city manager shall designate the appropriate city staff member or members as contact person or persons for all matters related to distributed generation interconnection.
(b) 
The city manager shall identify to the Public Utility Commission of Texas the contact person or persons for all matters related to distributed generation interconnection.
(c) 
The city manager shall cause the city internet web site to provide convenient access to the names, telephone numbers, mailing addresses and electronic mail addresses for the distributed generation contact person or persons.
(d) 
The designated contact person or persons shall review applications for distributed generation with the requisite attached technical documentation and determine whether there is compliance with the city technical requirements for interconnection and parallel operation of distributed generation.
(e) 
When the contact person is satisfied that a customer has complied with the application requirements and that the customer's system complies with the technical requirements for interconnection and parallel operation of distributed generation, the contact person shall recommend to the city manager that an agreement be executed with the customer for the interconnection and parallel operation of distributed generation. The city manager shall review the application and technical information submitted, and if the city manager finds that the customer has complied with the application requirements and that the customer's system complies with the technical requirements for interconnection and parallel operation of distributed generation, the city manager shall execute an agreement with the customer in the form approved by the city council.
(Ordinance 12-2022 adopted 10/13/2022)
(a) 
All interconnections shall comply with all applicable state and federal laws and regulations, including without limitation, P.U.C. SUBST.R.25.212.
(b) 
All interconnections shall comply with local building and electric codes as adopted and amended by the city. Installation of all interconnections shall be inspected by the city. Inspection and approval of the installation by the city is a condition of interconnection and parallel operation of distributed generation.
(c) 
Variations from the technical requirements herein must be reviewed and approved by the city manager prior to implementation. Variations in the point of interconnection must be approved by the city manager and included in the agreement approved by the city council.
(Ordinance 12-2022 adopted 10/13/2022)
The customer shall provide and install a manual load break switch that provides a clear indication of the switch position at the point of interconnection to provide separation between the City of Weimar ("city") electrical system and the customer's electrical generation system. The location of the disconnect switch must be approved by the city. The disconnect switch shall be easily visible, mounted separately from metering equipment, readily accessible to city personnel at all times, and capable of being locked in the open position with a city padlock. The city reserves the right to open the disconnect switch isolating the customer's electrical generating system (which may or may not include the customer's load) from the city electrical system for the following reasons:
(1) 
To facilitate maintenance or repair of the city electrical system.
(2) 
When emergency conditions exist on the city electrical system.
(3) 
When the customer's electrical generating system is determined to be operating in a hazardous or unsafe manner or unduly affecting the city electrical system waveform.
(4) 
When the customer's electrical generating system is determined to be adversely affecting other electric consumers on the city electrical system.
(5) 
Failure of the customer to comply with applicable codes, regulations and standards in effect at the time.
(6) 
Failure of the customer to abide by any contractual arrangement or operating agreement with the city.
(Ordinance 12-2022 adopted 10/13/2022)
(a) 
Voltage.
The city shall endeavor to maintain the distribution voltages on the electrical system but shall not be responsible for factors or circumstances beyond its control. The customer shall provide an automatic method of disconnecting generation equipment from the city electrical system within ten (10) cycles should a voltage deviation greater than +5% or -10% from normal be sustained for more than thirty (30) seconds (1,800 cycles), or in the event of a voltage deviation greater than +10% or -30% from normal be sustained for more than ten (10) cycles. If high or low voltage complaints or flicker complaints result from the operation of the customer's electrical generation, the customer's generating system shall be disconnected until the problem is resolved to the satisfaction of the city.
(b) 
Frequency.
The city shall endeavor to maintain a sixty-hertz nominal frequency on the electrical system. The customer shall provide an automatic method of disconnecting generation equipment from the city electrical system within fifteen (15) cycles should a deviation in frequency of +0.5 Hz or -0.7 Hz from normal occur.
(c) 
Harmonics.
In accordance with IEEE 519, the total harmonic distortion (THO) of voltage shall not exceed five (5) percent of a pure sine wave of sixty-hertz frequency or three (3) percent of the sixty-hertz frequency for any individual harmonic when measured at the point of interconnection with the city electrical system. Also, the total current distortion shall not exceed five (5) percent of the fundamental frequency sine wave. If harmonies beyond the allowable range result from the operation of the customer's electrical generation, the customer's generating system shall be disconnected until the problem is resolved.
(d) 
Flicker.
The distributed generation facility shall not cause excessive voltage flicker on the city electrical system. This flicker shall not exceed three (3) percent voltage dip, in accordance with IEEE 519 (section 10.5), as measured at the point of interconnection.
(e) 
Power factor.
The customer's electrical generation system shall be designed, operated and controlled at all times to provide reactive power requirements at the point of interconnection from 0.95 lagging to 0.95 leading power factor. Induction generators shall have static capacitors that provide at least ninety-five (95) percent of the magnetizing current requirements of the induction generator field. The city may, in the interest of safety, authorize the omission of capacitors. However, where capacitors are used for power factor correction, additional protective devices may be required to guard against self-excitation of the customer's generator field.
(Ordinance 12-2022 adopted 10/13/2022)
The customer shall provide approved protective equipment necessary to immediately, completely and automatically disconnect the customer's electrical generation equipment from the city electrical system in the event of a fault on the customer's system, a fault on the city system or loss of source on the city system. Such protective equipment shall conform to the criteria specified in UL 1741 and IEEE 1547. The customer's generating system shall automatically disconnect from the grid within ten (10) cycles if the voltage on one (1) or more phases fall and stays below seventy (70) percent of nominal voltage for at least ten (10) cycles. The automatic disconnecting device may be of the manual or automatic reclose type and shall not be capable of reclosing until after the city service voltage and frequency are restored to within the normal operating range and the system is stabilized.
(Ordinance 12-2022 adopted 10/13/2022)
The customer shall be solely responsible for coordination and synchronization of the customer's electrical generating system with all aspects of the city electrical system. The customer also assumes all responsibility for any damage or loss that may occur from improper coordination and synchronization of its generating system with the city electrical system.
(Ordinance 12-2022 adopted 10/13/2022)
The actual metering equipment required, its voltage rating, number of phases and wires, size, current transformers, and number of input and associated memory are dependent upon the type, size and location of the electric service provided. In situations where power may flow both in and out of the customer's electrical system, power flowing into the customer's electrical system may be measured separately from power flowing out of the customer's electrical system. The city will provide, subject to existing rate schedules at the time of application, the metering equipment necessary to measure capacity and energy delivered to and from the customer. The rate that the city may pay a customer as a credit for net metering (adding electricity to the city power grid) is $0.04 per kwh. Any excess credit will not rollover after December 31st of each year.
(Ordinance 12-2022 adopted 10/13/2022)
If the city determines that an interconnection study is necessary, the city shall perform the study under reasonable terms and conditions agreed upon by both the customer and city and at the customer's sole expense. No study fee will be charged if the proposed generation site is not on a networked secondary and if all of the following apply:
(1) 
Proposed generation equipment is pre-certified. Generation equipment that is less than twenty (20) kW AC shall be considered pre-certified if a UL 1741 listed inverter that also meets IEEE 1547 specifications is used as well as UL 1703 listed PV modules.
(2) 
Proposed generation system does not expect to export more than fifteen (15) percent of total load on the feeder.
(3) 
Proposed generation system does not contribute more than twenty-five (25) percent of the maximum possible short circuit current of the feeder.
(Ordinance 12-2022 adopted 10/13/2022)
The distributed generation facility must have interrupting devices capable of interrupting the maximum available fault current, an interconnection disconnect device, a generator disconnect device, an over-voltage trip, an under-voltage trip, an over/under frequency trip and a manual or automatic synchronizing check (for facilities with standalone capability). Facilities rated over ten (10) kW, three-phase, must also have reverse power sensing and either a ground over-voltage or a ground over-current trip depending on the grounding system. Grounding shall be done in accordance with UL 1741. IEEE 1547 and NEC article 250.
(Ordinance 12-2022 adopted 10/13/2022)
(a) 
Synchronous machines:
(1) 
The distributed generation facility's circuit breakers shall be three-phase devices with electronic or electromechanical control.
(2) 
The customer is solely responsible for proper synchronization of its generator with the city system.
(3) 
The excitation system response ratio shall not be less than 0.5.
(4) 
The generator's excitation system shall conform to the field voltage versus time criteria specified in ANSI Standard C50. 13-1989.
(b) 
Induction machines:
The induction machines used for generation may be brought up to synchronous speed if it can be demonstrated that the initial voltage drop at the point of interconnection is within the flicker limits specified in this document.
(c) 
Inverters:
(1) 
Line-commutated inverters do not require synchronizing equipment.
(2) 
Self-commutated inverters require synchronizing equipment.
(Ordinance 12-2022 adopted 10/13/2022)
The distributed generation equipment shall be designed, installed, operated and maintained in accordance with, but not limited to, ANSI standards, UL standards, IEEE standards, the National Electrical Code, ERCOT Operating Guides and any other applicable local, state or federal codes, statutes, and regulations. In the case of a conflict between the requirements in this article and any of the aforementioned standards, regulations, or codes, this article shall prevail.
(Ordinance 12-2022 adopted 10/13/2022)