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:
The person or persons designated by the city manager to serve
as the city’s contact for all matters related to distributed
generation interconnection.
The city manager and/or duly authorized representative.
The Public Utility Commission of Texas.
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.
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.
The form of application of a customer seeking interconnection
and parallel operation of distributed generation with the city’s
electric system.
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.
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.
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.
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.
The physical connection of distributed generation to the
utility system in accordance with the requirements of this division
so that parallel operation can occur.
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.
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.
The operation of distributed generation while the customer
is connected to the city’s electric system.
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.
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.
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.
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)
