This division 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 1245, sec. 1.1, adopted 7/17/18)
The city is authorized to enact this division by the Texas Utility Code Ann., section 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, Texas Utility Code Ann, section 39.101(b)(3) entitles all Texas electric customers access to on-site distributed generation. Finally, Texas Utility Code Ann, section 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 1245, sec. 1.2, adopted 7/17/18)
As used in this division, the following words and terms shall have the meanings as set forth below:
City contact person.
The person or persons designated by the city manager to serve as the city’s contact for all matters related to distributed generation interconnection.
City manager.
The city manager and/or duly authorized representative.
Commission.
The Public Utility Commission of Texas.
Customer.
A person or entity interconnected to the city’s electric system for the purpose of receiving or exporting electric power from or to the city’s electric system.
DG agreement.
An agreement between a customer and the city that sets forth the contractual conditions under which a company and a customer agree that one or more facilities may be interconnected with the city’s electric system.
DG application.
The form of application of a customer seeking interconnection and parallel operation of distributed generation with the city’s electric system.
Distributed generation (DG).
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’s electric system.
Distributed generation owner.
An owner of distributed generation, the customer on whose side of the meter distributed generation is installed and operated, regardless of whether the customer takes ownership of the distributed generation, or a person who by contract is assigned ownership rights to energy produced from distributed generation located at the premises of the customer on the customer’s side of the meter.
Electric or electrical system.
The city electric distribution system consisting of, in general, transformers, conductors, wires, poles, breakers and services for distributing electrical power to the city’s electric grid and delivering electric service to customers or consumers.
ERCOT.
The Electric Reliability Council of Texas, Inc. or successor independent organization under PURA, section 39.151 for the power region to which the city’s system is connected.
Interconnection.
The physical connection of distributed generation to the utility system in accordance with the requirements of this division so that parallel operation can occur.
Manual disconnect device.
A manual switch at the point of interconnection that provides clear indication of the switch position, and when in the open position isolates the distributed generation from load unrelated to generation of electricity or operation of the facility.
Network service.
Two or more utility primary distribution feeder sources electrically tied together on the secondary (or low voltage) side to form one power source for one or more customers. The 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 while the customer is connected to the city’s 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 division relating to safety and reliability by an entity approved by the commission.
Pre-interconnection study.
A study or studies that may be undertaken by the city in response to its receipt of a completed DG application. Pre-interconnection studies may include, but are not limited to, service studies, coordination studies and utility system impact studies.
Stabilized.
The city’s electric system is considered stabilized when, following a disturbance, the system returns to the normal range of voltage and frequency for a duration of two minutes or a shorter time as mutually agreed by the city and the customer.
(Ordinance 1245, sec. 1.3, adopted 7/17/18)
This division applies to all persons or entities that desire to interconnect or operate in parallel a distributed generation system within the city electric system.
(Ordinance 1245, sec. 1.4, adopted 7/17/18)
(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 apply to the city by completing a city DG application form and execute a DG agreement with the city that establishes the terms and conditions for the interconnection and parallel operation of the distributed generation system.
(b) 
The city manager has 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 division, DG agreement and in accordance with all applicable city codes and applicable state and federal laws and regulations.
(c) 
The interconnection shall not be energized prior to the execution of the DG agreement.
(Ordinance 1245, sec. 1.5, adopted 7/17/18)
Distributed generation with installed capacity greater than 1 MW, which exports energy into the city’s electric distribution system, is required to be registered with ERCOT.
(Ordinance 1245, sec. 1.6, adopted 7/17/18)
(a) 
The city contact person or persons for all matters related to distributed generation interconnection is provided on the city’s DG customer information materials and the city’s web site.
(b) 
The designated city DG contact person shall review applications for distributed generation with attached technical documentation and determine compliance with the city technical requirements for interconnection and parallel operation of distributed generation.
(c) 
When the city is satisfied that the customer has complied with the application requirements and that the DG system complies with the technical requirements for interconnection and parallel operation of distributed generation, the city DG contact person shall recommend to the city manager that a DG agreement be executed with the customer for the interconnection and parallel operation of distributed generation.
(Ordinance 1245, sec. 1.7, adopted 7/17/18)
(a) 
All DG interconnections shall comply with PUC Electric Substantive Rules, section 25.212 and successors. In addition, all DG interconnections shall comply with applicable state and federal laws and regulations.
(b) 
All DG interconnections shall comply with local building and electric codes. Building codes are enforced by the city code enforcement division. Installation of all interconnections shall be inspected by the city to ensure compliance with city DG specifications and requirements. 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 must be reviewed and approved by the city prior to implementation. Variations in the point of interconnection must be approved and included in the DG agreement approved by the city manager.
(Ordinance 1245, sec. 2.1, adopted 7/17/18)
The distributed generation facility must have an interrupting device 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 stand-alone capability).
(Ordinance 1245, sec. 2.2, adopted 7/17/18)
The customer shall provide and install a manual load break switch that provides clear indication of the switch position at the point of interconnection to provide separation between the 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 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 city.
(Ordinance 1245, sec. 2.3, adopted 7/17/18)
(a) 
Voltage.
The customer shall provide an automatic method of disconnecting generation equipment from the city electrical system within 10 cycles should a voltage deviation greater than +5% or -10% from normal be sustained for more than 30 seconds (1800 cycles) or a voltage deviation greater than +10% or -30% from normal be sustained for more than 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.
(b) 
Frequency.
The city shall endeavor to maintain a 60-hertz nominal frequency on the electrical system. The customer shall provide an automatic method of disconnecting generation equipment from the city electrical system within 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 (THD) of voltage shall not exceed 5% of a pure sine wave of 60-hertz frequency or 3% of the 60-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 5% of the fundamental frequency sine wave. If harmonics 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 3% 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 0.97 lagging to 0.95 leading power factor. Induction generators shall have static capacitors that provide at least 97% 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 1245, sec. 2.4, adopted 7/17/18)
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 10 cycles if the voltage on one or more phases falls and stays below 70% of nominal voltage for at least 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 1245, sec. 2.5, adopted 7/17/18)
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, and the customer assumes all responsibility for damage or loss that may occur from improper coordination and synchronization of its generating system with the city electrical system.
(Ordinance 1245, sec. 2.6, adopted 7/17/18)
(a) 
The actual metering equipment required, its voltage rating, number of phases and wires, size, current transformers, number of input and associated memory is dependent upon the type, size and location of the electric service provided. Customer shall pay for the installation of the data recorder (meter) that is capable of measuring the “KWh Delivered” (energy delivered to the customer) and the “KWh Received” (energy received by the city electric distribution system) in intervals established by the city, using a single meter or two-meter configuration.
(b) 
The city may waive this fee if a standard electric meter can be programmed or configured to support the required measurements and functionality.
(Ordinance 1245, sec. 2.7, adopted 7/17/18)
(a) 
The city may perform pre-interconnection studies, which shall include service study, coordination study, and utility system impact study, as needed and determined in the sole discretion of the city. In instances where such studies are deemed necessary, the scope of such studies shall be based on the characteristics of the particular distributed generation facility to be interconnected and the city’s distribution system at the specific proposed location. The city may charge customer fees for pre-interconnection studies that recover the costs of performing such studies. Any modifications or additions to the city’s electric system identified through the study as required for the safe and reliable interconnection of customer’s facility shall be solely at the customer’s expense. Customer shall not acquire any ownership in such modifications or additions to city’s electric system.
(b) 
The city will determine whether a pre-interconnection study is necessary, based on relevant engineering factors including the output of the system, the location of the system and other city distribution system factors. If the pre-interconnection study is deemed necessary, the city shall perform the study under reasonable terms and conditions agreed upon by both the customer and the 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.
(A) 
Generation equipment that are less than 20 kW AC shall be considered pre-certified if system meets appropriate codes and standards provided by NESC (National Electrical Safety Code), ANSI (American National Standards Institute), IEEE (Institute of Electrical and Electronic Engineers), NEC (National Electric Code), UL (Underwriter’s Laboratory), technical requirements and local building codes and other applicable ordinances in effect at the time of the installation of the DG system.
(B) 
Proposed generation system does not expect to export more than 15% of total load on the feeder.
(C) 
Proposed generation system does not contribute more than 25% of the maximum possible short circuit current of the feeder.
(Ordinance 1245, sec. 2.8, adopted 7/17/18)
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 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 1245, sec. 2.9, adopted 7/17/18)
(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 division.
(Ordinance 1245, sec. 2.10, adopted 7/17/18)
(a) 
Line-commutated inverters do not require synchronizing equipment.
(b) 
Self-commutated inverters require synchronizing equipment.
(Ordinance 1245, sec. 2.11, adopted 7/17/18)
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 and statutes. In the case of a conflict between the requirements in this division and any of those standards or codes, this division shall prevail.
(Ordinance 1245, sec. 2.12, adopted 7/17/18)
Any person violating this division by interconnecting distributed generation to the city electric system without a complete DG application and executed DG agreement shall have the DG system disconnected from the city electric distribution system, until all violations have been corrected to the satisfaction of city.
(Ordinance 1245, sec. 2.13, adopted 7/17/18)