Transcript
Interconnection Guidelines For
The Dairyland Power Cooperative (DPC) Transmission System
Dairyland Power Cooperative July 2010
DPC gratefully acknowledges permission granted by Xcel Energy (formerly Northern States Power Company) to utilize their “Interconnection Guidelines For Transmission Interconnected CustomerOwned Generation” as a basis for this document. Transmission and Generation Interconnection Guidelines
Dairyland Power Cooperative 3200 East Avenue South La Crosse, WI 54602-0817
DAIRYLAND POWER COOPERATIVE
TRANSMISSION AND GENERATION INTERCONNECTION GUIDELINES TABLE OF CONTENTS Page I.
Introduction........................................................................................................... 4
II.
General Policy ...................................................................................................... 5
III.
Interconnection Technical Requirements ........................................................... 18
IV.
Interconnection Substation Configuration ........................................................... 31
V.
Protective Devices for the Interconnection ......................................................... 36
VI.
Pre-parallel Requirements and Inspection.......................................................... 46
VII.
Operating Guidelines.......................................................................................... 47
VIII.
Glossary ............................................................................................................. 50
IX.
References ......................................................................................................... 55
APPENDICES Appendix A - DPC Metering and Telemetry Requirements ........................................... 60 Appendix B - Pre-Parallel Acceptance Testing Standards ............................................ 65 Appendix C - Working Clearances ................................................................................ 68 Appendix D - Fencing.................................................................................................... 68
I.
INTRODUCTION A.
Objectives This guide serves as a reference for establishing the DPC/Customer interconnection to operate generation and/or transmission facilities in parallel with DPC’s Transmission System. Generation is defined as any device producing (or releasing from storage) electrical energy. Such devices include rotating generators driven by steam turbines, internal combustion engines, or hydraulic turbines; windmills; photovoltaic arrays; fuel cells; battery arrays; or other energy sources with a Direct Current (DC) to Alternating Current (AC) inverter or any other electric generating device. Parallel Operation is defined as the operation of Customerowned generation with output terminals connected directly or through an intermediary’s system to DPC’s Transmission System. Parallel Operation may be long-term, or momentary (“make before break,” “hot” or “closed-transition” transfer). Technical terms used in this guide are defined in the Glossary. This document provides guidance to meet the minimum requirements for safe and effective operation of the interconnection. It provides technical guidelines to assist the Customer in establishing the interconnection in an efficient and consistent manner. This document shall not be construed as modifying any existing agreements which establish rights and obligations of both DPC and the Customer. DPC reserves the right to revise this document without notice. Any Customer intending to interconnect generation with the DPC System must follow the Midwest ISO (MISO) interconnection process as outlined on their website. The interconnection process on the MISO web site is titled “Attachment X”. To use DPC’s Transmission System to deliver power, the Customer must request transmission service under MISO’s Transmission Tariff. Often the entity purchasing the plant energy and capacity will request transmission services; not the generating Customer. Approval is based on the capability of the system to provide the requested service.
B.
Authority The federal regulatory agencies having authority over electric service requires DPC to provide safe, adequate, efficient and reasonable service. The Federal Energy Regulatory Commission (FERC) has authority over
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any interconnection to the electric power system and has accepted the North American Electric Reliability Council’s (NERC’s) standards and practices. DPC’s interconnection requirements comply with these standards and practices. Any Customer desiring to generate in parallel with DPC is required to comply with DPC’s requirements. II.
GENERAL POLICY The electrical transmission facilities owned and/or operated by Dairyland Power Cooperative in the states of Minnesota, Wisconsin, Iowa, and Illinois are referred to as "the DPC Transmission System." The requirements stated in this guide are applicable for generation operated in parallel with the DPC Transmission System. The requirements are intended to achieve the following:
Provide comparable reliability and service to all users of the DPC Transmission System. Ensure the safety of the general public, DPC customers and DPC personnel. Minimize any possible damage to the electrical equipment of DPC, DPC customers and others. Minimize adverse operating conditions on the DPC Transmission System. Permit the Customer to operate generating equipment in parallel with the DPC Transmission System in a safe, reliable and efficient manner. Meet the applicable FERC, NERC, MISO, and future ISO, requirements and regulations.
Before any generator may interconnect and operate in parallel with the DPC Transmission System, they must comply with the interconnection requirements defined herein. A.
Financial Obligation Associated with Parallel Interconnection The Customer will reimburse DPC fully for its costs to the extent allowed by FERC. FERC/ MISO policy will guide the allocation of costs between the Customer and DPC. The following are examples (but not a complete list) of expenses that may be billable to the Customer: 1. 2.
Land, rights-of-way, licensing, engineering, station development costs, etc. The interconnecting substation, DPC transmission facility upgrades, or other related system modification costs. The cost allocation of the required interconnection facilities and system upgrades, if any, will be determined on a case by case basis in order to reflect the unique circumstances of each case of interconnection. FERC/MISO precedent will guide the cost allocation between the generator Customer and DPC.
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3.
Meter installation, testing, and maintenance, including all parts and other related labor. 4. Meter reading and scheduling. 5. Telemetry installation, testing, and maintenance, including all parts and other related labor. 6. Operating expenses, including communication circuits 7. Securing MISO acceptance. 8. Protective device installation/equipment cost and related labor. 9. Review of design, inspection and testing costs. 10. Programming costs to incorporate generation data into DPC's energy management system.
B.
Ownership Because DPC is responsible for the integrity and reliability of its Transmission System, the ownership boundary between the DPC Transmission System and the Customer’s System is the high side disconnecting device of the generation step-up and/or the reserve station auxiliary transformer unless otherwise agreed to by DPC and the Customer. In addition, DPC will own all the relaying and control systems associated with its transmission equipment from the high side disconnecting device to DPC’s Transmission System. The Customer will provide a visible open interconnecting device at the point of interconnection to the DPC Transmission System. The Customer is to provide the land for the interconnection substation and provide an easement for DPC to access and construct its facilities. If DPC equipment must be upgraded to allow for the interconnection under the guidelines expressed herein, then DPC will continue to own the upgraded equipment.
C.
C.
DPC Standard Equipment
Any equipment DPC will own, operate, or maintain will be manufacturer and type standard to the DPC System, to the extent possible. For Customer owned equipment which DPC will operate or maintain, such equipment will meet the technical specifications described in Section V. In addition, the Customer must pay for the training of DPC personnel to operate and maintain such equipment. The Customer must also maintain a stock of any spare parts necessary and make them available to DPC maintenance personnel or contract employees (consistent with spare parts DPC requires for similar equipment).
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All equipment, the operation or failure to operate, which would result in the opening of the transmission path through the interconnection, must conform to the technical specifications described in Section V. D.
Design and Construction of Interconnection Facilities DPC will either design and construct, or arrange for these services, to build the required transmission facilities in the interconnecting substation. DPC may, at its option, contract with the Customer or others for any or all of this. The Customer will own and construct from the visible open interconnecting device to the Customer’s generator, including the generator step-up transformer and station auxiliary transformer.
E.
Protective Devices Protective devices, which are defined in this document (e.g., relays, circuit breakers), must be installed by the owning party to disconnect the Customer's generation from the DPC System whenever a fault or electrical abnormality occurs. Such equipment must coordinate with existing DPC equipment and provide comparable levels of protection as practiced on DPC’s Transmission System. Major factors generally determining the type of protective devices required include: 1. The type and size of the Customer's generating equipment 2. The location of the Customer on the DPC System 3. The manner in which the installation will operate (one-way vs. two-way power flow) The specific requirements will be determined in the Interconnection and Facilities Studies. In addition to the protective devices, the addition of Customer generation may require modifying the DPC or neighboring transmission system. Each request for generation addition will be handled individually. DPC will solely determine on a comparable basis, the protective devices, transmission system modifications and/or additions required. DPC will work with the Customer to achieve an installation that meets the requirements of both the Customer and DPC. The Customer shall bear the costs of protective devices and DPC Transmission System modifications required to permit the operation of parallel generation.
F.
Operation of Transmission Interconnection Facilities DPC will operate (switch) all equipment which it owns and will do so under the MISO RC direction depending on the voltage class of the equipment.
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DPC may, at its option, contract with the Interconnecting Party or another Transmission Operator to provide for any or all of its operation. Any operations of interconnected transmission equipment must be under the direction of the responsible Transmission Operator. All interconnected transmission facilities must be under control of a NERC-certified Transmission Operator. G.
Responsibility and Approval DPC does not assume responsibility for protection of the Customer's generating equipment or of any other Customer equipment. The Customer is solely responsible for protecting their equipment to prevent damage from faults, imbalances, or other disturbances on their own system or on the DPC Transmission System. DPC will not be responsible for damage to the Customer’s equipment due to out-of-phase reclosing. Such an event will likely cause damage to the generator and must be addressed by the Customer. Technical aspects addressing protection requirements are expanded in Section VII. The process defined in this document concludes with DPC approval for a parallel generation interconnection. Approval implies that DPC has reviewed the interconnection to ensure that the DPC System is not adversely affected by operation of the parallel generation. DPC will not assume any liability or responsibility for Customer-owned equipment through the approval process.
H.
Compliance with Governing Entities Requirements and Approvals The requirements set forth by this document are intended to comply with the Public Utility Regulatory Policies Act (PURPA), the final rules on Open Access (FERC Orders 888, 889), all applicable local, state and federal regulatory agency requirements and additionally the applicable requirements of other entities related to owners and operators of electric systems and associated interconnected generation. These include entities (or succeeding entities) such as MRO (or a replacement regional reliability organization [RRO]), the North American Electric Reliability Council (NERC), Rural Utilities Service (RUS) and/or MISO an Independent System Operator (ISO). The Customer is also expected to work closely with DPC to keep abreast of changes in regulatory requirements and to comply with them as they develop. The Interconnection requirements for generation will vary depending upon issues such as:
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The DPC Transmission System interconnection voltage Interconnection power flow (one-way or two-way) Size of the proposed generation It is the responsibility of the Customer to obtain all permits and approvals of the governing entities to allow the siting of its proposed generator. DPC may, at its option, choose to obtain any or all of those permits and approvals required for facilities it will own. The Customer must comply with applicable electrical and safety codes, studies, reporting requirements, policies and standards. All interconnected generators’ installations must be reviewed and approved by MISO. Customers adding generation will be responsible for all study work required to obtain these approvals.
All generators operated normally parallel with the DPC System must satisfy NERC policies and standards and MRO system design standards for generation including providing data and other information. The interconnecting Customer and DPC must agree on how the Customer will accomplish these requirements. These standards require interconnected power system additions to maintain or improve the regional system security, reliability and transfer capability. Any interconnecting generator must determine their compliance with the NERC and MRO policies and standards and provide such information as is required. I.
Self Generators A Customer which owns and operates generation is required to obtain or provide for ancillary services or portions of such services as required by FERC, NERC, or MISO for any electric load served from the interconnected electric grid. These services can be provided in whole or in part through DPC services, by the Customer, or by purchases from other utilities. However, the Customer must confirm with the DPC System Operation Center (SOC) that it is in compliance at all times with these requirements.
J.
Interconnecting Generation Customer Rights An Interconnecting-Generating Customer meeting the requirements of these guidelines only has the right to interconnect and operate a generator in parallel with the DPC Transmission System. It does not have the right to deliver power and energy over DPC’s transmission facilities. Nor does meeting these guidelines imply the DPC
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Transmission System can accommodate the delivery of the Customers power and energy over the transmission network. To use DPC’s Transmission System, the Customer must request transmission service under MISO’s Tariff. Often the entity purchasing the plant energy and capacity will request transmission services; not the generating Customer. Approval is based on the capability of the system to provide the requested service.
III.
INTERCONNECTION TECHNICAL REQUIREMENTS The following requirements apply to all generating equipment operated normally in parallel with the DPC Transmission System. All interconnections must meet the applicable regional and NERC standards along with the requirements of MISO acting as the Regional Transmission Organization (RTO) for the DPC system. This applies to all three-phase and single-phase generators or inverter installations. A.
General Requirements
1.
Pool Emergency Requirement The generation Customer must agree to make its generation available for call by DPC as the LBA Operator for MRO/MISO emergencies, if the generation has this capability.
2.
MRO Generating Testing Requirement The generation Customer must agree to perform a generation test of each generator per MRO guidelines. This is typically a four hour test run of the generator to record specific load and output data. This test can take place during the generator’s normal run. The Customer is responsible for this annual generation test cost.
3.
Modeling Information The generation Customer will annually forecast the firm MW and MVAR usage on each plant reserve station auxiliary system, for when the generator is off-line or starting/stopping whichever is greater. All generator/exciter/governor manufacturer data sheets must be available for modeling in transient/voltage stability, short circuit, and
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relay setting calculation programs. This includes generator reactive capability curves and exciter saturation curves. The Interconnecting Party shall provide DPC and MISO (at the time of application for interconnection) model data (logic block diagrams; transfer function representations; definitions for all parameters including gains, time constants, and limits; and corresponding numerical values) for the proposed generation and any associated power conversion equipment and controls, if appropriate IEEE standard models exist. If IEEE models do not exist, applicant shall provide suitable user model(s) and associated documentation for use with the Power Technologies, Inc., “PSS/E” simulation program to facilitate steady-state (“powerflow”), dynamic, and transient stability simulation of the generation power equipment’s behavior.
B.
Operating Limits To minimize adverse operating conditions of electric service that is provided to other Customers on the DPC System, all generation operating in parallel with the power system shall meet the following operating criteria: 1.
Voltage a.
General The Customer's generating equipment shall not cause excessive voltage excursions. Variable output machines (wind) with fluctuations in plant MW output may cause fluctuation in power system voltage. To achieve adequate speed of response to such variations, plants relying on switched shunt capacitors to control such variations must have the capacitor banks equipped with “rapid discharge” circuits capable of rendering the capacitors available for reinsertion within 5 seconds of de-energization.
b.
Steady State Voltage Range The Customer should expect normal operating voltage of +/5% from nominal and contingency operating voltage of +/10%. The plant should be capable of start-up whenever the voltage at the points of interconnection are within the +/10% of nominal range. If the auxiliary equipment within the plant cannot operate within the above range, the plant will
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need to provide regulation equipment to correct the voltage level excursions to this equipment. c.
Dynamic Voltage Range The DPC electric transmission system is designed to avoid experiencing dynamic voltage dips below 70% due to external faults or other disturbance initiators. Accordingly, dropout of contactors of controls associated with static or rotor circuits or any essential generator auxiliaries should not occur during dynamic power system voltage swings to levels as low as 70%. High voltage swings of up 1.2 are also possible.
2.
Flicker Customers are not allowed to produce flicker to adjacent Customers which exceeds the DPC guideline shown below. The Customer will be responsible and liable for corrections if the generator is the cause of objectionable flicker levels.
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DPC Voltage Flicker Guideline 7
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Percent Voltage Dip
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4
DPC GUIDELINE
3
Border Line of Irritation Border Line of Visibility of Flicker
2
1
0 1 20
2
5
10
20 30
1
Dips per Hour
2
5
10
20
30
1
Dips per Minute
2
5
10
Dips per Second
Frequency of Dips
30 0
12
6
3
2
1
30
12
6
3
Minutes
2
1
.3
.2
.1
Seconds
Time Between Dips
3.
Frequency Control The Customer’s operating frequency shall normally operate between 59.5 to 60.5 hertz. The Customer will operate its generator consistent with DPC guidelines and requirements concerning frequency control. Generators shall be equipped with governors that sense frequency, and: (a)
Governors shall provide a zero to ten percent (0-10%) adjustable setting nominally set at a five percent (5%) droop characteristic unless agreed otherwise by DPC.
(b)
Governors shall be maintained and tested in accordance with the manufacturer's specifications to maintain the performance stated in this section. The Customer shall, at its sole expense, be responsible for this maintenance and testing.
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(c)
Customer generating equipment must have short term capability for non-islanded low frequency operation not less than the following:
Generator Response to Frequency Instantaneous Tripping 62.2 Hz
Move to minimum Output
Delayed tripping is permitted per NERC guidelines 60.5 Hz
Continuous Operation
59.5 Hz
Move to maximum Output
Delayed tripping is permitted per NERC guidelines 57.8 Hz
Instantaneous Tripping
4.
Power Factor Requirements a. Minimum Power Factor Requirements Generating entities will be expected to provide for their own generator reactive power needs. All generator Customers are required to provide a steady state unity power factor, unless providing Reactive Supply and Voltage Control from the Generation Source Service. (The Customer can respond dynamically to meet system performance requirements.) b. Reactive Supply and Voltage Control from Generation Source Service The following is a FERC defined ancillary service. These are DPC’s present minimum requirements for such service. 11
However, the final requirements will be based on any mandated MRO (or applicable RRO), NERC, or ISO interconnection requirements. Any generator providing this service to the Load Balancing Area Operator must be able to automatically control the voltage level by adjusting the machine’s power factor within a continuous range based on the calculated (or tested) generating capability curve. The voltage setpoint that the generator needs to maintain will be established and adjusted as necessary by DPC’s System Operation Department. The plant must be capable of full reactive output whenever the voltage at the points of interconnection is within the range of .95 to 1.05pu. The use of a static VAR compensator(s) or similar device to meet these reactive requirements is acceptable. The Voltage Control Response Rate (for synchronous generators, the exciter response ratio) is the speed with which the voltage-controlling device reacts to changes in the system voltage. For a synchronous generator the excitation system response ratio shall not be less than 0.5 (five-tenths). The generator's excitation system(s) shall conform, as near as reasonably achievable, to the field voltage vs. time criteria specified in American National Standards Institute Standard C50.13-1989 in order to permit adequate field voltage during transient conditions. Non-synchronous generators should be designed to meet a similar Voltage Response Rate. 5.
Power System Stabilizers To comply with MRO Reliability requirements, generators 75 MVA and larger must be equipped with Power System Stabilizers to damp power oscillations, unless an exemption to this requirement is approved by MRO. The Power System Stabilizer is to be tuned to the DPC electric delivery system mode of oscillation.
6.
Harmonics The Customer's equipment shall not introduce excessive distortion to the DPC Systems voltage and current waveforms per the IEEE 519-1992. The harmonic distortion measurements shall be made at the point of interconnection between the Customer and the DPC System and be within the limits specified in the tables below. DPC
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advises that the Customer analyze their compliance with the IEEE 519-1992 standard during the early stages of planning and design. VOLTAGE DISTORTION LIMITS Bus Voltage At PCC
Individual Voltage Distortion IHD %
Below 69 kV 69 kV to 138 kV 138 kV and above
Total Voltage Distortion THD %
3.0 1.5 1.0 From: IEEE 519 Table 11.1
5.0 2.5 1.5
CURRENT DISTORTION LIMITS FOR NON-LINEAR LOADS AT THE POINT OF COMMON COUPLING (PCC) FROM 120 TO 69,000 Volts Maximum Harmonic Current Distribution in % of Fundamental Harmonic Order (Odd Harmonics) I(sc)/I(l)
<11
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