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AU S T I N E N E R G Y

I N TE RC ONN E C T I O N GU I D E F O R C U S T O ME R -O W N E D P O W E R PR ODU C T I O N

F O R F A C I L I T I E S 5 0 k W to < 10M W

T A B L E O F C ON TE N T S

PAGEA. P U RP O S E .............................................................................................................................04

B. D E F I N I T I ON S ......................................................................................................................06

C. COMPLIANCE WITH APPLICABLE LAWS AND INSTALLATION RULES

1. Compliance with Laws ...................................................................................................08

2. Compliance with Installation Rules.................................................................................08

3. Applicability.....................................................................................................................08

4. Individual Assessment .....................................................................................................08

4. Inspection .........................................................................................................................085. Enforcement .....................................................................................................................08

D. GENERAL REQUIREMENTS FOR SEPARATE SYSTEMS

1. Required Customer Data..................................................................................................09

2. Switching .........................................................................................................................09

3. Self Protection..................................................................................................................09

4. Verification ......................................................................................................................09

5. Field Inspection................................................................................................................09

E. GENERAL REQUIREMENTS FOR PARALLEL SYSTEMS

1. Required Customer Data..................................................................................................10

2. Interconnection Equipment..............................................................................................10

3. Maintenance of Protective Equipment. ...........................................................................10

4. Self Protection..................................................................................................................11

5. Capital Cost Responsibility .............................................................................................11

6. Inspection .........................................................................................................................11

7. Operating Approval .........................................................................................................11

8. Operating Safety...............................................................................................................11

F. MINIMUM TECHNICAL REQUIREMENTS FOR PARALLEL SYSTEMS

1. Manual Disconnect ..........................................................................................................12

2. Voltage and Flicker..........................................................................................................12

3. Frequency .........................................................................................................................12

4. Harmonics ........................................................................................................................13

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5. Fault and Loss of Source. ................................................................................................13

6. PowerFactor....................................................................................................................13

7. Reconnection to AE Service............................................................................................13

8. Coordination and Synchronization ..................................................................................13

9. Metering ..........................................................................................................................14

10. Interconnect Studies........................................................................................................1411. Dedicated Service ...........................................................................................................14

12. Protection Requirements.................................................................................................15

13. Relay Settings .................................................................................................................16

14. Additional Requirements for Three-Phase Generators ..................................................16

15. Communication...............................................................................................................17

16. Other Devices..................................................................................................................18

G. TE C HN I C A L E X C E P T I ON S ..............................................................................................18

H. OPERATIONAL AND NON-OPERATIONAL METER DATA

1. Meter Data........................................................................................................................19

2. Equipment ........................................................................................................................19

3. Maintenance .....................................................................................................................19

4. Billing Record. .................................................................................................................19

5. Interruption of MeterData ...............................................................................................19

6. Maintenance of CustomerEquipment .............................................................................19

7. No CustomerModifications ............................................................................................19

8. Property of Austin Energy ...............................................................................................19

9. Subject to Laws, Ordinances ...........................................................................................19

I. C E R T I F I C A T I O N C OD E S AN D S T ANDA R D S ..............................................................20

Appendix A. INTERCONNECTION APPLICATION FORM

1. Application Checklist. .....................................................................................................22

2. Application Form .............................................................................................................23

3. Customer Information......................................................................................................24

4. Distributed Generation Facility Information ...................................................................25



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A. PURPOSE

Senate Bill 7 (SB 7), Act of May 21, 1999, 76th Legislature, Regular Session, chapter 405, 1999

Texas Session Law Service 2543, 2561 (Vernon) to be codified as an amendment to the Public

Utility Regulatory Act (PURA), Texas Utilities Code Annotated 39.101(b)(3) now entitles all

Texas electric customers to access on-site distributed generation.

The purpose of this manual and guidelines is to outline the process for connecting a distributed

generation (DG) facility as well as to define the minimum technical and financial requirements for

safe integration of customer-owned power production facilities with the AE Distribution System

(Note: the typical AE Distribution system is 12.47kV). This information is provided in an effort

to maintain safe and reliable service to generating facilities and customers.

This manual is based on the applicable Federal Energy Regulatory Commission (FERC)

guidelines(h tt p : // www .f erc .gov /indu st r i e s / e l ec t r i c /indu s-a c t / g i/ s m a ll -g e n .asp), Public Utility

Commission ofTexas (PUCT) rules (if applicable)

(h ttp : // www .pu c .stat e .tx.u s / e l ec t r i c /bu s in e ss /d g /d g /d g.c f m) , as well as ERCOT regulations forSystem Operators and accepted industry practices and standards.

I nt erc onn ec tio n p r o ce s sThere are three types of interconnections on the AE Distribution system that are defined by the

following categories:

1. S mal l Commerci al or Resid en ti al Systems of 50 k W or less.

Systems 50 kW or less shall refer to the ESPA procedure detailed in the Austin Energy Design

Criteria Manual which can be found on the Austin Energy website at:

http://www .austinenergy.com/about%20us/Rates/index.htm

a. Inverter based systems- Primarily Solar PV

b. Synchronous motor systemsWind generation, standard fossil-fuel based induction

motor generators.

http://www.ferc.gov/industries/electric/indus-act/gi/small-gen.asphttp://www.ferc.gov/industries/electric/indus-act/gi/small-gen.asphttp://www.ferc.gov/industries/electric/indus-act/gi/small-gen.asphttp://www.ferc.gov/industries/electric/indus-act/gi/small-gen.asphttp://www.puc.state.tx.us/electric/business/dg/dg/dg.cfmhttp://www.puc.state.tx.us/electric/business/dg/dg/dg.cfmhttp://www.puc.state.tx.us/electric/business/dg/dg/dg.cfmhttp://www.puc.state.tx.us/electric/business/dg/dg/dg.cfmhttp://www.puc.state.tx.us/electric/business/dg/dg/dg.cfmhttp://www.puc.state.tx.us/electric/business/dg/dg/dg.cfmhttp://www.austinenergy.com/about%20us/Rates/index.htmhttp://www.puc.state.tx.us/electric/business/dg/dg/dg.cfmhttp://www.puc.state.tx.us/electric/business/dg/dg/dg.cfmhttp://www.austinenergy.com/about%20us/Rates/index.htmhttp://www.ferc.gov/industries/electric/indus-act/gi/small-gen.asp


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2. Medi um Sys tems fro m 5 0 kW to


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B. DEFINITIONS

1. A E S y st e m : The Electric Utility System of Austin Energy (AE). A detailed map of the

service area is available on the Austin Energy Storm Center Website:

h ttp s : // my.a u s t in e n er gy.c o m /o u t ag e s /

2. C ustom er : Refers to both cogenerators and small power producers within the AE service

area who use conventional fossil fuels or alternative sources such as solar, wind or biomass

to produce power.

3. I EE E : Institute of Electrical and Electronics Engineers

4. I nt erc onn ec tio n : The physical means by which electric energy is received from a generating

source. The principal elements of an electric interconnection include transmission and

distribution circuits, transformers and switching devices such as circuit breakers, fuses and

isolating disconnect switches. Supplemental elements may include sensing devices and

protective relay equipment.

5. I nt erc onn ec tio n P oin t: The point at which energy first enters or leaves the line or apparatus

owned by the customer and leaves or enters the line or apparatus owned by AE and is the

point of common coupling as defined in IEEE1547. Typically, this is defined by where the

meter is located.

6. S uppl e m e nt ary El ec tr ic S er vi c e : Electric power required on a regular basis to serve a

portion of the customer's load in addition to that served by the customer's power source.

7. M a int e n a n c e El ec tr ic S er vi c e : Electrical power which is required to serve the customer's

load during specific prearranged periods of scheduled outage of the customer's powersource for maintenance orrepair.

8. I sol a te d S y st e m : A system in which there is no interconnection of the customer's power

source or load served by the customer's power source to an electrical circuit common with

the AE electric utility system. Customers dedicating their power production equipment to a

particular load without standby electric service from AE would be considered as having a

totally isolated system.

9. S e p ara te Sy st e m : A system in which there is no interconnection of the customers electrical

generation system in parallel with the AE electric utility system but whose load receives

standby service from AE. Customers dedicating their power production equipment to aparticular load and who receive standby electric service for the load from AE must be

capable of transferring the load between the two electrical systems in an open transition in

order to be considered as having a separate system; that is, the customer's power production

equipment is never connected to the AE electric utility system directly or indirectly through



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the load. Typical emergency backup generation systems with an automatic transfer switch

fall into this category.

10. P ara ll e l S y st e m : A system in which the customer's electrical generation system can be

connected to an electrical circuit common with the AE electric utility system. Customers

who receive supplementary electric service from AE will be considered as having a parallelsystem. This system allows for the flow of power from AE to the customer and from the

customer to AE. Typical distributed generation falls into this category.

11. U PS : An Uninterruptible Power Supply (UPS) system that is not normally capable of

backfeed into the AE system will be classified as a S e p ara te system. If the UPS system is

capable of backfeed into the AE system, it will be classified as a P ara ll e l system.

12. B ac k fee d : A situation whereby the normal power flow is reversed and current flows from

the customer system into the AE distribution system.

13. Mi cr o g r id : A microgrid is a local energy network offering integration of DG with localelectric loads, which can operate in parallel with the AE System or in an intentional

island mode. This is a new type of system being developed and includes the use of DG

paired with smart load shed/load management techniques to enable it to run in an islanded

configuration. AE procedures to handle this type of system have not been developed.

14. De di ca te d S er vi c e : A feeder or transformer, or both, in the AE Distribution system that

only serves a single customer.



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C. COMPLIANCE WITH APPLICABLE LAWS AND INSTALLATION RULES

1. C ompli a n c e w it h L aw s . All customer-owned power production facilities located in the AE

service area shall comply with the latest version of the Austin Electrical Utility Service

regulations, City of Austin Electrical Code (2512-12), NFPA 70 (National Electrical Code),the NESC (National Electrical Safety Code), as well as the most current version of all other

applicable federal, state, or local laws or ordinances as of date of installation. Refer to

Section I for a listing of additional codes and standards.

2. C ompli a n c e w it h I nst a ll a tio n R ul e s . All customer-owned power production facilities shall

also comply with the Installation Rules and Standards for Electric Service established for

the AE service area.

3. A ppli ca bility . The foregoing safety requirements shall apply whether or not a customer

owned production facility is interconnected to the AE system.

4. I ndividu a l A ss e ssm e nt . An individual assessment may be required. Because of variations in

AE electrical circuits and the multitude of possible generator types and capacities available

for customer applications, AE reserves the right to review and approve each request to

ensure that suitable protective devices and operating procedures for joint operation will be

installed. The customer may be responsible for any or all fees to perform these assessments

depending on the size of the proposed DG installation in addition to costs to perform the

interconnection as outlined in section E.6. Fee schedules are available online at:

h ttp : // www .a u s t in e n er gy.c o m /A b o u t % 20 U s/ R a te s/ f ee S c h e du le .pd f

5. I nsp ec tio n . All customer-owned power production facilities shall be inspected for

compliance with minimum safety code requirements and installation rules. Isolated systemswill also be inspected to ensure that the customer's load and power production equipment

are not connected to an electrical circuit in common with the AE system. Inspection

approval shall mean only that as of the date of the inspection, the customer's system met

minimum code requirements at the time of such inspection and shall not be construed as

endorsement, or approval or recommendation of a particular system design for the

customer's needs nor a representation that the facility continues to comply with such codes

following the inspection.

6. En f o rce m e nt . AE reserves the right to discontinue electric service to customers who fail or

refuse to comply with minimum requirements or applicable law or who as determined by

AE, to be operating their power production equipment in a hazardous or unsafe manner.AE may also pursue such other and further rights or remedies as are available to enforce

these requirements.

http://www.austinenergy.com/About%20Us/Rates/feeSchedule.pdfhttp://www.austinenergy.com/About%20Us/Rates/feeSchedule.pdfhttp://www.austinenergy.com/About%20Us/Rates/feeSchedule.pdfhttp://www.austinenergy.com/About%20Us/Rates/feeSchedule.pdf


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D. GENERAL REQUIREMENTS FOR SEPARATE SYSTEMS

1. R e qui re d C ustom e r Da ta . Any installation over 50 kW must be accompanied with a full set

of drawings and specifications that have been sealed by a Professional Engineer licensed in

the state of Texas. All drawings will be required to be in electronic files in either pdf orAutoCad 2008 dwg formats. Files larger than 3 MB should be sent in a zipped or

compressed format. Upon request, the customer shall submit to AE all technical data or

additional information required to evaluate the proposed customer electrical generating

facility.

2. S w it c hin g . The customer must be capable of transferring load between the customer's own

electrical generation system and the AE system in an open transition or non-parallel mode.

The transfer of load between systems can be accomplished by either an electrically or

mechanically interlocked switching arrangement which prevents both switches from being

in a closed position simultaneously.

3. S e lf P r ot ec tio n . The customer must provide adequate protection to ensure clearing of faults

on the customer's own electrical system.

4. Ver if ica tio n . For a Separate System, AE will require verification that the transfer scheme

meets the non-parallel requirement. Verification requires that the customer submit physical

layout and sealed electrical one-line drawings to AE upon request showing the site specific

relationship between the customer's load and electrical generating system and the AE

system.

5. F ie ld I nsp ec tio n . AE may also require a field inspection and/or demonstration of the

customer's power production facility under a fault condition to verify proper operation ofprotective devices and transferequipment.



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E. GENERAL REQUIREMENTS FOR PARALLEL SYSTEMS

1. R e qui re d C ustom e r Da ta . Any installation over 50 kW must be accompanied with a full set of

drawings and specifications that have been sealed by a Professional Engineer licensed in the

state of Texas. All drawingswill be required to be in electronic files in either pdf or AutoCad

2008 dwg formats. Files larger than 3 MB should be sent in a zipped or compressed format.Upon request, the customer shall submit to AE all technical data or additional information

required to evaluate the proposed customer electrical generating facility, including but not

limited to the following:

a. Physical layout drawings, including dimensions and interconnection distance;

b. Schematic drawings up to, and including, the interface to the AE system;

i. Electrical main one-line and three-line diagrams, and schematic diagrams

ii. System protection details

iii. Integration of DG grounding system with AE distribution system per IEEE1547.

iv. Detailed list of equipment: manufacturers name, model number and ratinginformation as well as operating ranges for frequency, voltage, current, power,

power factor, phase rotation, etc.

v. Manufacturer's test data or certification indicating compliance with national codes

concerned with radio noise, harmonic generation, and telephone interference factor

vi. Lightning protection and grounding details indicating conformance to NEC article

250

c. Coordination data such as;

i. Functional and logic diagrams

ii. Control and meter diagrams

iii. Conductor sizes and length and technical parameters for circuit impedancesiv. Any other data relevant to coordination of the customer system with the AE system

d. Synchronizing methods (if any)

2. I nt erc onn ec tio n Equipm e n t. All interconnection equipment on the customer's facility shall be

installed and maintained by the customer at their sole expense and in accordance with minimum

guidelines established by AE.

a. AE shall review and approve all customer-selected interconnection equipment and

proposed configuration

b. All Solar PV inverters shall be on the approved list published by the California EnergyCommission (CEC) on its websitehttp : //www . go s o la r californ ia.org .

3. M a int e n a n c e o f P r ot ec tiv e Equipm e n t. The customer shall provide a maintenance schedule and

perform maintenance of protective equipment at their sole expense at least; every two (2) years;

as mandated by current standards, equipment manufacturer recommendations; or as required by

http://www.gosolarcalifornia.org/http://www.gosolarcalifornia.org/http://www.gosolarcalifornia.org/http://www.gosolarcalifornia.org/http://www.gosolarcalifornia.org/http://www.gosolarcalifornia.org/


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AE to provide a safe, reliable system while operating in parallel with the AE system. Circuit

breakers must be trip-tested by the customer at least once each year.

a. M a int e n a n c e R ec o r d s . Maintenance records for parallel systems must be provided to

AE upon request.

4. S e lf P r ot ec tio n . The minimum protection requirements are designed and intended to protect the

Austin Energy electrical distribution system only. The customer shall provide at their sole

expense, all devices necessary to protect the customer's electrical generating system by

conditions that may occur on the AE system resulting in interruptions and restorations of

electrical service. The equipment so installed must protect the customer's electric generating

system from overvoltage, undervoltage, overload, short circuits including ground fault

conditions, open circuits, phase imbalance and reversal, over and under frequency conditions

and other injurious electrical conditions that may arise during the operation of the AE system.

5. C a pit a l C os t R e sponsibilit y . The customer is required to bear all initial and subsequent costs

associated with the change-out, upgrading or addition of protective devices, transformers, poles,line, services, meters, switches, and associated equipment and devices beyond that which would

be required to provide normal service to the customer if no generation was involved. The

customer shall be invoiced for all material and labor that are required in excess of those covered

by other applicable installation charges or fees (see appropriate schedules). AE shall supply the

customer upon request a written cost estimate prior to any work being done.

6. I nsp ec tio n . AE reserves the right to inspect the customer's facility periodically and test the

performance of any equipment or devices associated with the interconnection or parallel

operation of power production equipment. All interconnectionrelated protective functions and

associated batteries shall be tested. A periodic test report log shall be maintained. Testing shall

include but is not limited to, for example, the tripping of the circuit breakers by the protectiverelays. The customer shall provide appropriate access to all facilities for the purpose of such

inspections.

7. O p era tin g A pp r ov a l. The customer shall not start up, test or operate electric generating

equipment in parallel with the AE electric system without the prior written consent of AE. The

customer is required to provide, at their cost, a 3rd party commissioning agent to verify that all

work has been correctly performed and the system installation complies with all applicable

codes and standards. AE shall have the right to disconnect customers who have interconnected

without AE authorization.

8. O p era tin g S afe ty . Adequate protection and documented switching orders and operationalprocedures must be jointly developed and followed by the customer and AE for each customer

power production facility operating in parallel with the AE system. These operating procedures

must be approved by both the customer and AE. The customer shall be required to furnish,

install, operate and maintain in good order and repair and be solely responsible for, without cost



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to AE, all facilities required for the safe operation of a customer generation system in parallel

with the AE system.

F. MINIMUM TECHNICAL REQUIREMENTS FOR PARALLEL SYSTEM

1. M a nu a l D is c onn ec t. A manual load break disconnect switch shall be available at the customer's

main service point to provide a separation point between the customer's electrical generation

system and the AE electric utility system. AE will coordinate and approve the location, make

and type of the disconnect switch. The disconnect switch shall be mounted separately from the

metering equipment, readily accessible to AE personnel at all times, and capable of being

locked in the open position with an AE padlock. AE 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 AE system for the following reasons:

a. To facilitate maintenance or repair of the AE electric system or of the distributed

generation system;b. During AE electric system emergency conditions;

c. When the customer's electrical generating system is determined to be operating in a

hazardous or unsafe manner or unduly affecting AE's voltage waveform;

d. When the customer's electrical generating system is determined to be adversely affecting

other electric consumers on the AE system;

e. Failure of the customer to comply with applicable codes, regulations and standards in

effect at that time;

f. Failure to abide by any contractual arrangement or operating agreement with AE.

2. V olt a g e a n d F li c k er . AE shall endeavor to maintain the voltages on the AE system but shall not

be responsible for factors or circumstances beyond its control. If the customer's electricalgeneration equipment has voltage control capability, it shall be operated in the manual mode

with power factor control consistent with the power factor requirement set out below. The

customer owned equipment will not cause AE system voltage to go outside of the limits set by

ANSI C84.1. The customer shall provide an automatic method of disconnecting its generation

equipment from the AE system per IEEE standard 1547 S ec tio n 4 - I nt erc onn ec tio n tec hni ca l

sp ec if ica tion s a n d re qui re m e nts . In addition, the customer's electrical generation shall not cause

excessive voltage flicker on the AE system. In accordance with IEEE 519, the flicker shall not

exceed 3.0% voltage dip, measured at the point of common coupling. 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.

3. F re qu e n cy . AE will endeavor to maintain a 60-hertz nominal frequency on the AE system. If

the customer's electrical generation equipment has speed or frequency control, it shall be

operated in the manual droop mode. In accordance with IEEE standard 1547, the customer

shall provide an automatic method of disconnecting its generation equipment from the AE



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system within 10 cycles should a deviation in frequency of +0.5 Hz or -0.7 Hz from a 60-hertz

base occurs in its operating frequency.

a. The automatic disconnecting device may be of the manual or automatic reclose type and

shall not be capable of reclosing until the AE System voltage and frequency return to

normal range and the system is stabilized for the duration specified in (7) below.

4. Har moni c s . In accordance with IEEE Standards 519 and 1547 (and UL1741 for inverter based

systems), the output sine wave distortion from the customer's electrical generation system shall

not cause voltage harmonic content or total harmonic distortion (THD) in excess of 5% of the

fundamental 60-hertz frequency nor 4.0% of the fundamental frequency for any individual

harmonic when measured at the point of common coupling with the AE system.

5. F a ul t a n d L os s o f S ou rce . In accordance with IEEE standard 1547, in the event of a fault on the

customer's system or a fault or loss of source on the AE system the customer shall provide an

automatic method of disconnecting its generation equipment from the AE system within 10

cycles should the voltage on one or more phases fall below 50.0% of nominal voltage on the

AE system serving the customer premises at the point of common coupling.

a. The automatic disconnecting device may be of the manual or automatic reclose type and

shall not be capable of reclosing until the AE System voltage and frequency return to

normal range and the system is stabilized for the duration specified in (7) below

b. The type and size of the device shall be specified by AE depending upon the

installation. Adequate test data or technical proof that the device meets the above

criteria must be supplied by the customer to AE.

c. To enhance reliability and safety and with AEs approval, the customer may employ a

modified relay scheme with delayed tripping or blocking using communications

equipment between the customer and AE.

d. This disconnect timing also ensures that the generator is disconnected from the AE

System prior to automatic re-close of breakers.

6. P o we r F ac to r . 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 95% of the magnetizing current requirements of the induction

generator field. AE 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.

7. R ec onn ec tio n to A E S er vi c e . After any disturbance resulting in a service interruption or

breaker actuation, no Distributed Generation source may reconnect until the AE System voltage

and frequency return to normal range and the system is stabilized for a period up to 5 minutes or

as required by AE.



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8. C oo r din a tio n a n d S y n c h r oni z a tio n . The customer shall be responsible for coordination and

synchronization of the customer's electrical generating system with all aspects of AE's electrical

system, and the customer assumes all responsibility for damage or loss that may occur from

improper coordination and synchronization of its generator with the AE system.

a. All required fault-detection relays shall coordinate with AEs devices, as necessary.b. All interconnection relays shall be set to provide overlapping or coordinated

protection to prevent extensive damage should an interrupting device fail to clear

when required. The line-protection schemes shall be able to distinguish between

generation, inrush, and fault current.

c. Where the existing relay schemes have to be reset, replaced, or augmented with

additional relays to coordinate with the customers new facility, all work shall be done

at the customers expense.

d. The customer must place the AE-required relays at a location where a fault on any

phase of AEs interconnected line(s) can be detected.

e. If AE requires transfer-trip protection, the customer shall provide and pay for all the

required communication circuits and equipment based on the protection studies.

f. The customer should contact Austin Energy to determine the phase rotation at their

proposed site.

9. M e ter in g . AE will provide in accordance with approved AE Electric Rate Schedules and AE

Design Criteria manual at the time of application, the metering equipment necessary to measure

capacity and energy delivered to, or received from, the customer's facility. Where applicable

per section F.12, AE shall provide at the customer's expense the necessary additional advanced

power factor revenue metering equipment for data acquisition and evaluation of the

interconnection to the AE system. Contact AE Complex Metering: (512) 505-7045

10. I nt erc onn ec t studi e s . Detailed interconnect studies may be required if the generation is

connected to AEs distribution system and AE determines it to be necessary for safety and

reliability purposes.

a. Th ree- P h a s e F ac iliti e s ra te d ov e r 5 0 , bu t no t mo r e th a n 500k W: Interconnect study

typically not required for equipment pre-certified to UL1741. If an interconnect study is

desired, AE to bear all costs for studies performed.

b. Th ree- P h a s e F ac iliti e s ra te d mo r e th a n 50 0 k W bu t no t mo r e th a n 200 0 k W:

i. Interconnect study typically required. Study may be at customers expense

depending on proposed facility and location on a case-by-case basis.

ii. Austin Energy shall provide written reports within 6 weeks.

c. Th ree- P h a s e F ac iliti e s ra te d mo r e th a n 200 0 k W bu t le s s th a n 1 0 M W:

i. Interconnect study typically required at customers expense.



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ii. Austin Energy shall determine the cost and timeline for performing a detailed

interconnect study.

11. De di ca te d S er vi c e . AE will determine the need and feasibility for dedicated service on a case-

by-case assessment of each customer-owned power production facility. The customer is

responsible for all connection charges above standard service.

a. Dedicated Transformer: AE may require a dedicated transformer; the customer shall be

connected to the AE electric utility system through a dedicated power transformer provided

at the sole expense of the customer.

b. Dedicated Feeder: Proposed Distributed Generation facilities may not represent greater

than 25% of the existing feeder load or 25% of the maximum available fault available on

the circuit.

12. Protection Requirements.

a. Th ree- P h a s e F ac iliti e s ra te d ov e r 5 0 k W, bu t no t mo r e th a n 50 0 k W, mus t h a v e :

i. Interrupting devices capable of interrupting the maximum available fault current

ii. An interconnection disconnect device

iii. A generator disconnect device

iv. An over-voltage trip

v. An under-voltage trip

vi. An over/under frequency trip

vii. An automatic synchronism check relay(if generator is synchronous or self-

commutated)

viii. Reverse power sensing if the facility is not exporting (unless the generator is less than

the minimum load of the customer)ix. 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 and NEC Article 250

x. Advanced power factor revenue metering to provide usage information for reporting

to ERCOT

xi. Refer to conceptual drawing in Figure 1 (at end of section)

b. Th ree- P h a s e F ac iliti e s ra te d mo r e th a n 50 0 k W bu t no t mo r e th a n 200 0 k W mus t h a v e :

i. Interrupting devices capable of interrupting the maximum available fault current

ii. An interconnection disconnect device

iii. A generator disconnect device

iv. Industrial grade relays that can provide the following functions at a minimum:1) An over-voltage trip with sensing/readout by phase

2) An under-voltage trip with sensing/readout by phase

3) An over/under frequency trip with sensing/readout by phase

4) An automatic synchronism check relay (for facilities with stand-alone

capability)



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5) 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 and

NEC Article 250

6) Reverse power sensing by phase if the facility is not exporting (unless the

facility is less than the minimum load of the customer)

v. If the facility is exporting power, the power direction protective function may be usedto block or delay the under frequency trip with the agreement of AE

vi. Advanced power factor revenue metering to provide usage information for reporting

to ERCOT

vii. Energy Management System (EMS) or Supervisory Control and Data Acquisition

(SCADA) circuit between the generators site and AEs control center for monitoring

may be required

c. Th ree- P h a s e F ac iliti e s ra te d mo r e th a n 200 0 k W bu t le s s th a n 1 0 M W mus t h ave :

i. Interrupting devices capable of interrupting the maximum available fault current. If

the facility is exporting to the AE system, it shall have a redundant circuit breaker

unless a listed device suitable for the rated application is used,ii. An interconnection disconnect device,

iii. A generator disconnect device,

iv. Utility grade relays approved by AE Substation and Relay Engineering and

compatible with AE relay communication. The relay shall provide the following

functions at a minimum:

1) An over-voltage trip with sensing/readout by phase,

2) An under-voltage trip with sensing/readout by phase,

3) An over/under frequency trip with sensing/readout by phase,

4) An automatic synchronism check relay (for facilities with stand-alone

capability),

5) Reverse power sensing by phase if the facility is not exporting (unless thefacility is less than the minimum load of the customer).

6) Telemetry/transfer trip (may be required as part of a transfer tripping or

blocking protective scheme) to be done in accordance with IEEE1547

7) 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 and

NEC Article 250.

8) If the facility is exporting power, the power direction protective function may

be used toblockor delay the under frequency trip with the agreement of AE.

9) On-board data acquisition and event log to record actual readings for all events.

v. An automatic voltage regulator (AVR) (for facilities with stand-alone capability),vi. Advanced power factor revenue metering to provide information to ERCOT and AE

sufficient information to determine the status of the generation facility during system

disturbances.



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vii. Energy Management System (EMS) or Supervisory Control and Data Acquisition

(SCADA) circuit between the generators site and AEs control center for

monitoring.

13. R e la y S e ttin g s . The settings for all distribution interconnections shall be approved by AE

Transmission and Substation Engineering and Construction in conjunction with SystemEngineering and IEEE1547.

14. Additional Requirements for Three-P hase Generat ors.

a. All generating units must comply with all of the applicable standards of ANSI and IEEE.

b. S y n c h r onou s m ac hin e s

i. The distributed generation facilitys circuit breakers shall be three-phase devices

with electronic control.

ii. The Customer is solely responsible for proper synchronization of its generator with

the AE system.iii. The generators excitation system shall conform to the field voltage versus time

criteria specified in the most recent version of ANSI Standard C50.13.

iv. For generating systems greater than two (2) megawatts (MW) the customer shall

maintain the AVR of each generating unit in service and operable at all times. AE

shall be notified if the AVR is removed from service for maintenance or repair.

c. I ndu c tio n m ac hin e s

i. The induction machines used for generation may be connected and brought up to

synchronous speed (as an induction motor) if it can be demonstrated that the initial

voltage drop at the point of interconnection is within the flicker limits specified in

this document.

d. I nv er ter s

i. Line-commutated inverters do not require synchronizing equipment.

ii. Self-commutated inverters require synchronizing equipment. Any installation of

this type must be approved by AE.

15. C ommuni ca tion.

For facilities greater than two (2) megawatts (MW), AE may require that a communication

channel be provided by the customer to provide communication between AE and the

customers facility. The channel will be a mutually agreed upon medium and shall comply with

the requirements of IEEE 1547.3.

16. O th e r De vi ce s . The foregoing provides a statement of the minimum requirements for parallel

operation on the AE system. In addition, AE will have the right to specify certain protective

devices including relays and circuit breakers that the customer must install at the customer's

expense to operate in parallel with AE's system to protect the safety of its employees and



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.

equipment, maintain the reliability of the system or improve the accuracy of its metering

equipment

Figure 1. Simplified Conceptual Diagram for small (


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H. OPERATIONAL AND NON-OPERATIONAL METER DATA

1. M e te r D a ta . Upon request and if economically feasible, AE may make available to the

customer electric Operational and/or Non-Operational data from the billing meter(s).

2. Equip m e n t. In order to provide Operational and/or Non-Operational meter data, e.g. KYZPulse Service, DNP meter data, MODBUS meter data etc. it may be necessary for AE to

install additional equipment in excess of that equipment necessary for the metering of the

customer's electric service. The customer shall be responsible for all labor and material

costs associated with the installation and maintenance of such equipment.

3. M a int e n a n ce . Equipment used for Operational/Non-Operational meter data will be

maintained by AE.

4. B illin g R ec o r d . AEs electric metering installation shall in all instances be used to establish

the customer's energy and demand record for billing purposes.

5. I nt err uptio n o f M e te r D a ta . AE reserves the right to interrupt the meter data at any time

without notice to the customer in the event of equipment malfunction or to perform tests or

maintenance and in so doing assumes no responsibility for affecting the operation of

customer equipment. Whenever possible, AE will attempt to notify the customer of an

impending interruption but assumes no legal obligation to notify.

6. M a int e n a n c e o f C usto m e r Equip m e n t. The customer has the responsibility for the

installation and maintenance of all wiring and equipment on the customer side of the

contact terminal blocks.

7. N o C usto m e r M odi f ica tion s . Under no circumstances shall the customer modify, adjust, orinterrupt the operation of AE metering equipment.

8. P r op er ty o f AE . All metering equipment on AE's side of the customer's contact terminal

blocks is and shall remain the sole property of AE.

9. S ubj ec t to L a ws , O r din a n c e . All agreements for provision of value-added or ancillary

service(s) shall be subject to applicable state, federal and local laws, ordinances and

regulations.



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I. Cer t if ic a t io n C o des a nd S t a nd a rds(Refer t o t he m os t recent releas ed versi on of t he foll owi ng documents: )

City of Austin Electrical Code--h ttp :// www .aml egal .com/ au stin _tech manu al s/

IEEE1547 Standard for Interconnecting Distributed Resources with Electric Power Systems

(including use of IEEE 1547.1, 1547.2 and 1547.3)

UL 1741 Inverters, Converters, and Controllers for Use With Distributed Energy Resources IEEE

STD 929, IEEE Recommended Practice for Utility Interface of Photovoltaic (PV) Systems NFPA

70, National Electrical Code

IEEE STD C37.90.1, IEEE Standard Surge Withstand Capability (SWC) Tests for Protective

Relays and Relay Systems

IEEE STD C37.90.2, IEEE Standard Withstand Capability of Relay Systems to Radiated

Electromagnetic Interference from Transceivers

IEEE STD C37.108, IEEE Guide for the Protection of Network Transformers

IEEE STD C57.12.44, IEEE Standard Requirements for Secondary Network Protectors

IEEE STD C62.41.2, IEEE Recommended Practice on Characterization of Surges in Low

Voltage (1000V and Less) AC Power Circuits

IEEE STD C62.45, IEEE Recommended Practice on Surge Testing for Equipment Connected to

Low-Voltage (1000V and Less) AC Power Circuits

ANSI C84.1, Electric Power Systems and Equipment Voltage Ratings (60 Hertz)

IEEE STD 100, IEEE Standard Dictionary of Electrical and Electronic Terms

IEEE STD 519, IEEE Recommended Practices and Requirements for Harmonic Control in

Electrical Power Systems

NEMA MG 1, Motors and Generators

California Energy Commission(CEC)Solar Energy Resource h ttp :// www .gosol arcali f orni a.org/

http://www.amlegal.com/austin_techmanuals/http://www.amlegal.com/austin_techmanuals/http://www.gosolarcalifornia.org/http://www.gosolarcalifornia.org/http://www.amlegal.com/austin_techmanuals/http://www.gosolarcalifornia.org/


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Appendix AInterconnection Package and Forms



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Applic ati on P ac kage Chec klis t

1) Copy enclosed of completed Distributed Generation Application

2) Copy enclosed of completed ESPA Application

3) Copy enclosed of site electrical one-line diagram and schematic drawings showing the

configuration of all Distributed Generation equipment, current and potential circuits, and

protection and control schemes, signed and stamped by a licensed Professional Engineer

4) Copy enclosed of any site documentation that indicates the precise physical location of the

proposed distributed generation facility (e .g ., USGS topographic map or other diagram or

documentation).

5) Copy enclosed of proposed location of protective interface equipment on property

6) Copy enclosed of any site documentation that describes and details the operation of the

protection and control schemes.

7) Copy enclosed of schematic drawings for all protection and control circuits, relay current

circuits, relay potential circuits, and alarm/monitoring circuits (if applicable).

8) Enclosed initial payment per fee schedule. (re f e r t o S ecti on C .4)

Applic ant Signat ur e

I hereby certify that, to the best of my knowledge, all of the information provided in this Interconnection

Request is true and correct.

Interconnection Customer:

Date:



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Aus tin E nergy Dis tributed Genera tio n Applica tio n

(For facilities from 50 kW to


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I nterc onnecti on Cust omer I nf orm ati on

Legal Name of the Interconnection Customer (or, if an individual, individual's name)

Name:

Contact Person:

Mailing Address:

City: State: Zip:

Facility Location (if different from above):

Telephone (Day): Telephone (Evening):

Fax: E-Mail Address:

Alternative Contact Information (if different from the Interconnection Customer)

Contact Name:

Title:

Address:

Telephone (Day): Telephone (Evening):

Fax: E-Mail Address:

Application is for:

New Small Generating Facility Capacity addition to Existing Generating Facility

A) Ifcapacityadditiontoexistingfacility,pleasedescribe:

B) Provide existing Account Number

Will the Small Generating Facility be used for Net Metering? Yes No

Interconnection Customer or Customer-Site Load: kW (if none, so state)

Maximum Physical Export Capability Requested: kW



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D istri bu te d G e n er a ti on F a cilit y I n f o rm a ti on

(Data apply only to the Generating Facility, not the Interconnection Facilities.)

Technology Type: Renewable Non-renewable

Fuel Type: Solar Wind Diesel Natural Gas Fuel Oil

Other (state type)

Type of Generator: Synchronous Induction Inverter

Generator (or solar collector)

Manufacturer, Model Name & Number:

Version Number:

Nameplate Output Power Rating in kW: (Summer) (Winter)

Nameplate Output Power Rating in kVA: (Summer) (Winter)

Individual Generator Power Factor

Rated Power Factor: Leading: Lagging:

Inverter Manufacturer, Model Name & Number (if used):

Is the inverter on the CEC list of approved equipment? Yes No

List components of the Small Generating Facility equipment package that are currently certified:

Equipment Type Certifying Entity

1.

2.3.

4.

5.

Is the generation equipment compatible with the certified protective relay package? Yes No

List of adjustable set points for the protective equipment or software:

Note: A completed ESPA data sheet must be supplied with the Interconnection Request.



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Dist ri buti on Facilit y C haract eristi c Dat a (for i nvert er-bas ed machi nes )

Maxdesignfaultcontributioncurrent: Instantaneous orRMS?

Harmonics Characteristics:

DC offsetStart-uprequirements:

S m all Generati ng Facilit y C haracteristi c Dat a (for rot ating m achi nes )

RPMFrequency:

(*)NeutralGroundingResistor(IfApplicable):

S ynchronous Generat ors :

Direct Axis Synchronous Reactance, Xd: P.U.Direct Axis Transient Reactance, X' d: P.U.

Direct Axis Subtransient Reactance, X" d: P.U.

Negative Sequence Reactance, X2: P.U.

Zero Sequence Reactance, X0: P.U.

KVA Base:

Field Volts:

Field Amperes:

Inducti on Generat ors :

Motoring Power (kW):

Locked Rotor current

I22tor K (Heating Time Constant):

Rotor Resistance, Rr: P.U.

Stator Resistance, Rs: P.U.

Stator Reactance, Xs: P.U.

Rotor Reactance, Xr: P.U.

Magnetizing Reactance, Xm: P.U.

Short Circuit Reactance, Xd'': P.U.

Exciting Current:

Temperature Rise:

Frame Size:Design Letter:

Reactive Power Required In KVars (No Load):

Reactive Power Required In KVars (Full Load):

Total Rotating Inertia, H: Per Unit on kVA Base

Excitati on a nd Gover nor Syste m Dat a f or Sync hr onous Generat or s Only



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I nterc onnecti on F acilitie s I nf orm ati on

Will a transformer be used between the generator and the point of common coupling? Yes No

Will the transformer be provided by the Interconnection Customer? Yes No

T ra nsf orme r Dat a ( If Applica ble , f or Interc onnecti on Customer -Owne d T ra nsf or mer) :

Size: kVA Transformer Impedance: % on kVA Base

If Three Phase:

Transformer Primary: Volts Delta Wye Wye Grounded

Transformer Secondary: Volts Delta Wye Wye Grounded

Transformer Tertiary: Volts Delta Wye Wye Grounded

T ra nsf orme r Fus e Dat a ( If Applica ble , f or Interconnecti on Cust omer -Owne d Fuse):

(Attach copy of fuse manufacturer's Minimum Melt and Total Clearing Time-Current Curves)

Manufacturer: Type: Size: Speed:

Interc onnecti ng Circ ui t Brea ke r (i f a pplica ble):

Manufacturer: Type:

Load Rating (Amps): Interrupting Rating (Amps): Trip Speed (Cycles):

Interc onnecti on Pr otecti ve Relays ( If Applica ble) :

List of Functions and Adjustable Setpoints for the protective equipment or software:

Setpoint Function Minimum Maximum

1.

2.

3.

4.

Programmed Ti me Del ay f or Reconn ecti on af ter In terruption:

300 Seconds Other (specify)

If Discret e C om ponents:



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(Enclose Copy of any Proposed Time-Overcurrent Coordination Curves)

Manufacturer: Type: Style/Catalog No.: Proposed Setting:





Curre nt T ra nsf or me r Dat a ( If Applica ble):

(Enclose Copy of Manufacturer's Excitation and Ratio Correction Curves)

Manufacturer:

Type: Accuracy Class: Proposed Ratio Connection:

Manufacturer:


Pote ntial T ransf or me r Dat a ( If Applica ble) :

Manufacturer:


Manufacturer:



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