Customer Standard. Standard for Embedded Generation (5MW and above)

Transcription

1 Standard Version: 1 Released: 1/10/2014 STANDARD FOR EMBEDDED GENERATION (5MW AND ABOVE) Customer Standard Standard for Embedded Generation If this standard is a printed version, to ensure compliance, reference must be made to the Ergon Energy internet site or Energex internet site to obtain the latest version. Approver <insert name and position title of Asset Management General or Group Manager who reports to the Executive General Manager> If RPEQ sign off required insert details below. Ergon Energy Energex Certified Person name and Position Registration Number Certified Person name and Position Registration Number Robert Coggan Engineering Manager Substation Standards John Lansley 6371 Abstract: This Standard has been prepared by Energex and Ergon Energy to provide owners and Proponents of embedded generation installations information about their rights and obligations for the connection to and interfacing with the Distribution Network. Embedded generators are defined in the National Electricity Rules (NER) as generators connecting directly to the distribution network. This standard sets out the requirements for a Registered Participant or a Proponent of a Generating System greater than 5MW to connect to the Energex and Ergon Energy network for connection of a Generating System. Keywords: embedded, generation ENERGEX Limited ABN Ergon Energy Corporation Limited ABN

2 For definitive document version and control detail, please refer to the information stored on the Process Zone. Revision history Revision date Version number Author Description of change/revision 03/09/ John Lansley Rob Coggan Initial Version Document approvals Name Position title Signature Date Robert Coggan John Lansley Engineering Manager Substation Standards Senior Technology Solutions Enginneer Stakeholders / distribution list Name Title Role ENERGEX Limited ABN Ergon Energy Corporation Limited ABN

3 Table of Contents 1 Overview Purpose Scope 1 2 References Energex controlled documents Ergon Energy controlled documents Other documents 2 3 Legislation, regulations, rules, and codes 3 4 Definitions, acronyms, and abbreviations Definitions Acronyms and abbreviations 5 5 Network Connection Network Connection Agreement Network Connection Assets Access Standards Automatic access standard Minimum access standard Negotiated access standard Technical Considerations Permissible Generator Connection Arrangements 9 6 Connection Application Process General Requirements for Connection of Generators Connection Applications 9 7 Technical Requirements and Performance Standards General Network Connection and Voltage Level Nominal Interconnection voltage Energex Nominal Interconnection voltage Ergon Energy Lightning Insulation Levels for Surge Arrestors Power Frequency Network Characteristics Equipment Ratings 13 ENERGEX Limited ABN Ergon Energy Corporation Limited ABN

4 7.7 Fault Levels and Protection Impacts Earthing 14 8 Explanation of the NER and Related Technical Requirements Reactive power capability Quality of electricity generated Response to Frequency Disturbances Response to voltage disturbances Response to disturbances following contingency events Quality of electricity generated and continuous uninterrupted operation Partial Load Rejection Protection of generating systems from power system disturbances Protection systems that impact on power system security Protection to trip plant for unstable operation Frequency Control Impact on network capability Generator stability Network stability Network rating Inter regional power flow Voltage and reactive power control Reasonable approaches for voltage and reactive power control Voltage control strategy Control system Control system damping Control system testing Power system stabiliser The DNSP s Network Technical Study requirements Active Power Control Remote monitoring and control Communication Equipment Power Station auxiliary supplies Fault current 29 9 Other Technical Requirements 31 ENERGEX Limited ABN Ergon Energy Corporation Limited ABN

5 Annex A Generator Data Requirements 31 Annex B Example of Single Line Connection Diagram 33 B.1. Direct Connection of a high voltage generator 33 B.2. Connection of a generator through a transformer 34 Annex C Typical Protection Schemes 35 C.1. Customer and DNSP shared site 35 C.2. Customer and DNSP geographically diverse 36 C.3. Typical Generator Protection SLD 37 ENERGEX Limited ABN Ergon Energy Corporation Limited ABN

6 1 Overview 1.1 Purpose This Standard outlines the requirements for Registered Participants or Generators with embedded synchronous generators, asynchronous generators or inverter energy systems with a total nameplate rating exceeding 5 MW at a single connection point; that are intended to be connected to and operate in parallel with, any part of Energex and Ergon Energy s distribution network under normal operating conditions. This document has been developed to assist Generators with understanding technical requirements. It is not possible to maintain and update this document each time the National Electricity Rules (NER) changes, it is therefore a guide only and must not be relied upon to be current at all times. It is the document user s responsibility to satisfy themselves of compliance with the NER. If there is any inconsistency between this document and NER requirements, the NER will prevail. This document must not be used as a substitute to the NER. The clauses of the NER that are referred to in this standard are based on version 64 as released on the 1 st of August Scope The object of this Standard is to provide owners and Proponents of embedded generation installations information about their rights and obligations for connection to and interfacing with the Energex and Ergon Energy Network. 2 References 2.1 Energex controlled documents Document number or location (if applicable) Standard 657 Standard 233 Standard 3544 Document name Customer Standard for Small to Medium Scale Embedded Generation Customer Standard for Parallel Embedded Generation via Inverters Large Customer Connection Manual Document type Customer Standard Customer Standard Customer Standard <Check this is the latest version before use> Page 1 EX <Doc ID> Ver 1

7 2.2 Ergon Energy controlled documents Document number or location (if applicable) STNW1165 Document name Standard for Connection of Embedded Generators in the Ergon Energy Distribution Network Document type Customer Standard 2.3 Other documents Document number or location (if applicable) AS 2067 AS/NZS 3000 Document name Substations and high voltage installations exceeding 1 kv ac Electrical installations (known as the Australian/New Zealand Wiring Rules) Document type Australian Standard Australian Standard AS/NZS 3010 Electrical Installations Generating Sets AS 1931 Part 1 - High voltage - Test techniques - General definition and test requirements Australian Standard AS/NZS 3017 Electrical installations Testing Guidelines Australian Standard AS/NZS 3100 Approval and test specification - General requirements for electrical equipment Australian Standard AS 1319 AS/NZS Series AS/NZS 7000 AS 1359 Safety signs for occupational environment Electromagnetic compatibility (EMC) Overhead line design Detailed Procedures General Requirements for Rotating Electrical Machines Australian Standard Australian Standard Australian Standard Australian Standard AS Electric cables up to 36kV Australian Standard AS 2006 HV AC Switchgear & Control Gear CBS Greater than 1000V Australian Standard AS 2184 Low voltage switchgear Australian Standard AS 2373 Electric Cables Twisted Pair (For control and protection) Australian Standard AS 2374 Power Transformers Australian Standard <Check this is the latest version before use> Page 2 EX <Doc ID> Ver 1

8 Document number or location (if applicable) AS 4777 Document name Grid connection of energy systems via inverters Document type Australian Standard IEC Series Protection Relays Australian Standard AS Rotating Electrical Machines Part 22 Australian Standard AS/NZS Series Instrument Transformers Australian Standard AS/NZS Series High voltage switchgear and control gear Australian Standard 3 Legislation, regulations, rules, and codes This document refers to the following: Legislation, regulations, rules, and codes National Electricity Rules version 64 Queensland Electricity Regulations Definitions, acronyms, and abbreviations 4.1 Definitions For the purposes of this standard, the following definitions apply: Term Australian Energy Regulator Connection Asset Connection Applicant Connection Point Customer Customer Asset Definition A Federal Government body responsible for the economic regulation of electricity distribution services in the National Electricity Market. Those components of a transmission or distribution system which are used to provide connection services. A person who wants to establish or modify connection to a transmission network or distribution network and/or who wishes to receive network services and who makes a connection enquiry as described in NER clause The agreed point of supply established between Network Service Provider(s) and another Registered Participant, Non-Registered Connection Applicant or franchise Connection Applicant. A person who: engages in the activity of purchasing electricity supplied through a transmission or distribution system to a connection point; and is registered by AEMO as a Customer under Chapter 2. (of the NER). Electrical assets that are owned by the customer and are designed and constructed in accordance with AS/NZS <Check this is the latest version before use> Page 3 EX <Doc ID> Ver 1

9 Term Definition Distribution System Electricity Distributor Embedded Generator Embedded generating unit Generating unit Generator HV Interconnection Low Voltage Connection Point Small to Medium Scale Embedded Generation Installation A distribution network, together with the connection assets associated with the distribution network which is another transmission or distribution system. Energex is the owner, lessor and operator of the South East Queensland electricity distribution network. Ergon Energy is the owner, lessor and operator of the Queensland electricity distribution network outside of South East Queensland. A Generator, who owns, operates or controls an embedded generating unit. A generating unit connected within a distribution network and not having direct access to the transmission network. The actual generator of electricity and all related equipment essential to its function as a single entity. A person who engages in the activity of owning, controlling, or operating a generating system that supplies electricity to, or who otherwise supplies electricity to, a transmission or distribution system and who is registered with AEMO in that capacity. High Voltage nominally above 1kV. Synchronous parallel operation of an embedded generator to the electricity network The low voltage terminals of the distribution transformer. The DNSP is responsible for the operation and maintenance of the transformer and other HV equipment and the Connection Applicant is responsible for the installation, operation and maintenance of the all low voltage equipment. For the purpose of this Standard a small scale embedded generator is up to a capacity of 1 MW and a medium scale embedded generator is up to a capacity of 5 MW. This definition includes initiatives such as: Synchronous generators driven by hydro turbines; Synchronous generators driven by gas engines, gas turbines or diesel engines. This does not include plant which is operated and connected in parallel with the network by ENERGEX for the purpose of network or emergency support. Mini or Micro - Embedded Generation Installation National Electricity Rules National Metering Identifier For the purpose of this Standard a mini embedded generator has a nameplate rating greater than 2 kw and up to 10 kw single phase and 30 kw three phase. A micro embedded generator has a nameplate rating less than 2 kw. The National Electricity Rules govern the operation of the National Electricity Market. A National Metering Identifier as described in NER clause 7.3.1(d). <Check this is the latest version before use> Page 4 EX <Doc ID> Ver 1

10 Term Definition Network Network Coupling Point Network Augmentation Works Network Islanded Operation Network Technical Study Proponent Registered Participant Retailer Service Provider The apparatus, equipment, plant and buildings used to convey, and control the conveyance of, electricity to customers (whether wholesale or retail) excluding any connection assets. In relation to a Network Service Provider, a network owned, operated or controlled by that Network Service Provider. The point at which connection assets join a distribution network, used to identify the distribution service price payable by a Connection Applicant. Augmentation works required on network assets to enable a new project to be supplied or the increase in supply for an existing Connection Applicant. Generation is allowed to back feed into a portion of the distribution network that is isolated from the rest of the electricity supply network, typically as a result from a protection operation on the transmission or distribution network. A network study to evaluate the effects the proposed generation will have on the network under different loading conditions or in the event of particular faults. Means the Generator, Customer or developer or their agent (i.e. Consulting Engineers); A person who is registered by AEMO in any one or more of the categories listed in clauses 2.2 to 2.7 [of the NER] (in the case of a person who is registered by AEMO as a Trader, such a person is only a Registered Participant for the purposes referred to in clause 2.5A [of the NER]). However, as set out in clause 8.2.1(a1)[of the NER], for the purposes of some provisions of clause 8.2 [of the NER] only, AEMO and Connection Applicants who are not otherwise Registered Participants are also deemed to be Registered Participants. Means the holder of an electricity retail licence granted under the Electricity Act, 1994, who is contracted to sell electricity to the Customer at the Supply Address. A person or organisation authorised by the DNSP to carry out design and/or construction of certain electrical works. 4.2 Acronyms and abbreviations The following abbreviations and acronyms appear in this standard. Term, abbreviation or acronym ACA ACR AEMO AEMC AER AFLC AVR CB Definition Australian Communications Carrier Automatic Circuit Recloser Australian Energy Market Operator Australian Energy Market Commission Australian Energy Regulator Audio Frequency Load Control Automatic Voltage Regulator Circuit Breaker <Check this is the latest version before use> Page 5 EX <Doc ID> Ver 1

11 Term, abbreviation or acronym Definition DNSP HV LV NER NMI VT Distribution Network Service Provider (in this case Energex or Ergon Energy) High Voltage Low Voltage National Electricity Rules National Metering Identifier Voltage Transformer 5 Network Connection 5.1 Network Connection Agreement The Proponent of any embedded generation installation must enter into a Connection Agreement with the DNSP. These connection agreements are subject to commercial negotiations between the parties. The Connection Agreement encompasses both the technical and commercial aspects of the connection, addresses the standards and minimum technical requirements and specifies the terms and conditions including the connection charge, use of system charges and quality of supply in accordance with the NER. The Proponent shall indemnify the DNSP and accept liability for safety and supply quality issues that occur when the generator is operating. The DNSP will provide supply to local customer loads on a no risk basis. This requirement shall apply to all loads that are connected on the customer side of the network boundary and which can be supplied from the generator. 5.2 Network Connection Assets Connection assets are those assets which are dedicated to providing connection services to a customer or generator. The Network Coupling Point defines the boundary between Network and Connection Assets. The Connection Point identifies the ownership responsibility between the DNSP and the embedded generator. Revenue metering is normally installed as close as practicable to the Connection Point. Where Connection Assets include transformers, the Network Coupling Point and metering will normally be on the lower voltage (Generator) side of the transformer. HV metering will be installed in situations where the customer owns and operates the HV assets. <Check this is the latest version before use> Page 6 EX <Doc ID> Ver 1

12 Network (HV) Legend NCP Network Coupling Point CP Connection Point MP Metering Point NCP NCP NCP MP CP Connection Assets HV Connection Assets HV & LV Customer Owned Connection Assets HV MP CP Customers Electrical Installation Customer Facility or Development Site Customer 1 CP MP Customers Electrical Installation Customer Facility or Development Site Customer 2 Customers Electrical Installation Customer Facility or Development Site Customer 3 Figure 1 Asset Boundary Principles Augmentation of the existing distribution network may be required where necessary to upgrade parts of the existing distribution network (for example, to meet capacity requirements) or to extend the existing distribution network to facilitate the connection. Whether any such augmentation of the distribution network will be required will depend on a number of factors, including, but not limited to: the location and available capacity of the nearest power system infrastructure capable of facilitating the connection at the requested voltage levels and export levels; whether that infrastructure is owned by the distribution network service provider (Ergon Energy or Energex) or the transmission network service provider (Powerlink); the new infrastructure that is likely to be required to facilitate the connection of the generator, whether any of that infrastructure is already included in the relevant distribution network service provider's 5-year management plan, the agreed responsibility for constructing and owning that infrastructure, the classification of any services provided by the distribution network service provider and the relevant costs that will be incurred; the applicable Connection Policy of the distribution network service provider approved by the AER or the Capital Contributions Policy (where relevant); the impact of the proposed connection of the generator and the ongoing operation of that generator on the operation of the distribution and transmission networks and on the supply of electricity to other customers of the distribution network service provider (both in the short and long terms); and the ability to obtain necessary authorisations to carry out the works, and obtain tenure over land. In addition, certain large investments by distribution network service providers may be subject to a "Regulatory Investment Test", which requires the DNSP to participate in public consultation on the appropriate mechanism to manage an identified proposal on the distribution network. <Check this is the latest version before use> Page 7 EX <Doc ID> Ver 1

13 5.3 Access Standards Schedule S5.2.5 of the NER outlines the technical requirements for the connection of Generators to a Network Service Provider s (NSP) network. The technical requirements are referred to as access standards, namely, automatic, minimum and negotiated access standards. The access standards define the acceptable level of performance which a Generator must achieve for connection to a NSPs network. Any proposed performance standard less than automatic must be reviewed and if appropriate, agreed by the NSP and by Australian Energy Market Operator (AEMO) Automatic access standard Plant that meets the automatic access standard will not be denied access to the network because of the technical requirement of this standard. A generator that demonstrates this standard has shown sufficient capability for connection Minimum access standard The minimum access standard is the minimum technical level of performance that the NSP will consider for connection to the NSP s network. A plant that does not meet the minimum access standard will be denied access to the network. All access standards as outlined in S to S5.2.8 have a minimum access standard Negotiated access standard A negotiated access standard falls between the automatic and minimum access standards. It is an agreed standard of performance for the relevant technical requirement that the NSP will accept for access to the network. This standard should be as close as possible to the automatic standard. 5.4 Technical Considerations The following items must be addressed for all connections of embedded generation within the distribution network: Network Safety and Security; Network and Interconnection Protection Network Infrastructure Thermal Capacity; Network Voltage Control; Generator Fault Level Contribution; Generator Operating Power Factor; Quality of Supply Generated; Network Stability; and Operations. Prior to the connection of an embedded generator to the distribution network the DNSP will carry out a detailed analysis study of the network. The detailed analysis study and subsequent engineering report will identify any network operating constraints, network reinforcement requirements due to increases in fault levels, levels of Var support, network voltage compensation control, operating protocols and interface requirements between the Generator and the DNSP for the proposed connection. The DNSP will require information (as detailed in Section 6.2) to perform the detail analysis study and fees may apply. <Check this is the latest version before use> Page 8 EX <Doc ID> Ver 1

14 5.5 Permissible Generator Connection Arrangements Typical connection arrangements for embedded generators are given in Annex B. 6 Connection Application Process 6.1 General Requirements for Connection of Generators Generators cannot be connected to the DNSP s Network without the approval of the DNSP (Qld Electricity Regulation Section 28). Generators covered by this standard are Registered Participants with AEMO, or Proponents that elect to be treated under the provisions of Chapter 5 of the NER. Connection Applicants facilities shall comply with technical and performance standards as defined in the NER and the DNSP s Connection Agreement. (e.g. protection systems, disturbing loads, harmonic emission limits, and power factor). Detailed technical requirements for the connection of Generators are outlined in Section 7 and Section Connection Applications Proponents may make an application to the DNSP for connection of embedded generation. After considering the information provided by the DNSP in the enquiry response, the Connection Applicant may make a Connection Application in accordance with clause and 5.3.4A of the NER. The Connection Applicant must pay the application fee and include the information specified in the Connection Application Form. It will be necessary for the Connection Applicant and the DNSP to formalise the works program. This program may be amended on the agreement of both the DNSP and the Connection Applicant. Further information on the Connection Application is given in the Large Customer Connections Manual/Process. The Proponent shall submit the following technical information as part of their Connection Application. a. Detailed description of the proposed embedded generation facility; including, but not limited to: a. Number of generators b. Proposed operating mode(s) i.e peak load lopping, continuous operation, seasonal operation etc. c. Proposed interaction with the DNSP s distribution network under both normal network conditions and abnormal network conditions. d. Proposed local customer loads to be supplied from the embedded generation facility. e. Requirement for Customer Islanded operation. Note Network Islanded Operation is not permitted. f. Power export intentions refer also items (b) and (c) below. g. Known future staging / development of the embedded generation facility and/or local customer loads. b. Anticipated 24 hour local customer load profiles (both summer and winter) for the local customer loads that are to be normally supplied from the embedded generation facility. The profiles shall include apparent power (S), active power (P) and reactive power (Q) for both lightly loaded and maximum demand scenarios. <Check this is the latest version before use> Page 9 EX <Doc ID> Ver 1

15 c. Anticipated 24 hour power (import from network) / (export to network) profiles (both summer and winter) at the network connection point. The profiles shall include apparent power (S), active power (P) and reactive power (Q) for both lightly loaded and maximum demand scenarios. d. Site Plan showing the precise physical location of the embedded generator, the location of customer main switchboards and other relevant switchboards and the location of the DNSP substations and associated infrastructure. e. Detailed electrical single line diagram(s) showing the configuration of all embedded generation facility / customer equipment and circuits between the embedded generator(s) and the network connection point; including as a minimum: o All primary circuit equipment such as main switchboards, other switchboards, circuit breakers and isolators/load break switches. In particular, all points where the customer embedded generation facility and the DNSP distribution network can be connected / disconnected must be clearly identified. o All secondary protection and control equipment associated with the generator s connection and parallel operation with the DNSP distribution network including current transformers, voltage transformers, protection and control elements and sensing points. o Local customer load connections including any interconnections with other parts of the customer s installation. In particular, where interconnection with other parts of the customer s installation are proposed the means to prevent paralleling of the DNSP substations / transformers and/or unsynchronised connection to the DNSP distribution network shall be clearly identified. o All metering equipment associated with the generator and the import and export of power from/to the DNSP distribution network. o All proposed power factor correction equipment that will be installed within the part of the customer s installation that is supplied directly from the embedded generator. o Interlocking between plant items either mechanical or electrical shall be shown in a manner that allows design and operational staff to understand what impediments and/or safeguards will affect plant operation. f. Detailed functional block / schematic diagram of the protection and control systems relevant to the generator s connection to the DNSP distribution network showing the philosophy of the protection and control systems including all relevant relay current circuits, relay potential circuits, alarm and monitoring circuits, back-up systems, auxiliary power supply systems and proposed parameters / settings of all protection and control system elements. g. Detailed schematic diagram of the proposed earthing system arrangements for the embedded generation facility and associated customer electrical installation including all proposed earth connections, MEN connections and relevant switchboard earthing arrangements. h. For synchronous and asynchronous machines - generator data for each generator proposed to be installed as listed in Annex A. For inverter energy systems details of inverters and PV panels in accordance with Energex form 1552 or Ergon Energy form PW001701F100. In some cases additional information detailed in schedules 5.5.3, and of the NER may be requested by the DNSP. <Check this is the latest version before use> Page 10 EX <Doc ID> Ver 1

16 i. Full details of the proposed metering equipment and associated current transformers. Nomination of the Responsible Person for metering in accordance with the National Grid Metering. j. Full details of any proposed power factor correction equipment including: o Rating of capacitors individual stages and total installation (kvar) o o o o o o Capacitor Bank capacitance (microfarads) Rating of switching reactors (kvar) Inductance of switching reactor (millihenries) Resistance/Impedance of reactors (Ohms) Method of Switching including capacitor bank stage sizes Description of the automatic control of the power factor correction unit such that its operating characteristics can be determined. In accordance with S5.3.5 of the NER, power factor correction equipment shall be designed so as not to adversely impact the performance of the AFLC signals present on the DNSP s network. Sufficient detail must be provided to enable the DNSP to assess compliance with the minimum requirements outlined in this document, and conduct protection and load flow studies to assess the impact on plant fault ratings, protection scheme requirements and power export and import limits of existing infrastructure; and assess generator power factor and voltage limit requirements. 7 Technical Requirements and Performance Standards 7.1 General Connection Applicants facilities shall comply with technical and performance standards as defined in the NER and the DNSP s Connection Agreement. The equipment associated with each generating unit must be designed to withstand without damage the range of operating conditions which may arise consistent with the specified system standard of NER (Schedule S5.1a). Generators must comply with the performance standards and any attached terms or conditions of the Connection Agreement in accordance with a relevant provision of NER Schedules S Network Connection and Voltage Level Unless otherwise specified by the DNSP, a Generator is required to connect to the DNSP s network via a single point of connection at a voltage agreed with the DNSP. It is the Generator s responsibility to provide a circuit breaker at the point of connection, generator transformer(s) and all associated protection controls and ancillary equipment Nominal Interconnection voltage Energex Energex distribution networks normally include systems operating at 132kV, 110kV, 33kV, 11kV and 415V. Voltages as defined in AS apply. The nominal supply voltage for the low voltage network is 240 Volts, phase to neutral, and 415 Volts phase to phase with a tolerance of ± 6%. The nominal supply voltage for the 11 kv network is 11,000 Volts phase to phase with a tolerance of ± 5%. Grid connected inverters and grid protection devices shall be capable of operation within these parameters. <Check this is the latest version before use> Page 11 EX <Doc ID> Ver 1

17 The voltage level which an embedded generator will be connected depends primarily on the size of the generator, and the availability of distribution network in the area concerned. Typical voltage levels that various capacity generators may be connected to the Energex network are: Less than 1 MW capacity - LV Less than 3 MW capacity 11 kv 3 MW to 30 MW capacity 33 kv Greater than 30 MW capacity 110/132 kv These parameters may vary depending on the particular network characteristics. For instance, a long rural 11 kv network may not be suitable for a generator larger than 1 MW. An investigation will need to be undertaken by Energex to determine the most appropriate connection voltage Nominal Interconnection voltage Ergon Energy Ergon Energy distribution networks normally include systems operating at 132kV, 110kV, 66kV, 33kV, 22kV, 11kV and 415V. Voltages as defined in AS apply. The nominal supply voltage for the low voltage network is 240 Volts, phase to neutral, and 415 Volts phase to phase with a tolerance of ± 6%. The voltage level which an embedded generator will be connected depends primarily on the size of the generator, and the availability of distribution network in the area concerned. An investigation will need to be undertaken by Ergon Energy to determine the most appropriate connection voltage. 7.3 Lightning Insulation Levels for Surge Arrestors Surge arresters shall as a minimum be installed at the HV connection point. The minimum insulation levels and voltage ratings for the surge arresters are given in Table 1. Table 1 Lightning Impulse Withstand Voltages for Surge Arrestors Network Voltage (kv) Lightning Impulse Withstand Voltage (kvp) Nominal Surge Arrestor Rating (kv) <Check this is the latest version before use> Page 12 EX <Doc ID> Ver 1

18 7.4 Power Frequency See section 8.3 for required response to frequency disturbances. 7.5 Network Characteristics Energex and Ergon Energy networks are operated as either solidly or impedance earthed systems. 7.6 Equipment Ratings The equipment ratings on the DNSP or customer networks shall not be exceeded when the generation units and the system are in parallel operation. The DNSP will make available existing fault levels and equipment ratings on a project by project basis. Proponents shall provide a fault level study to the DNSP to demonstrate compliance. 7.7 Fault Levels and Protection Impacts In designing protection associated with embedded generation interconnection, faults and abnormalities to be considered are: In the generator itself In the embedded generation customer installation In the interconnection assets In the wider utility network Typical distribution feeders are fed radially from a utility substation. In these feeders, all of the short circuit fault current for faults on the feeder, as well as the load current, will come from the source substation. The magnitude of the fault current is determined by the impedances of the utility source, the transformers, reactors and feeder conductors/cables, and fault resistance. Embedded synchronous generators, will typically increase the fault current level at the fault point and reduce the current being supplied by the source substation to the point of actually causing a reversal of fault current flow in some circuits. The maximum and minimum values of fault current are an important consideration for any protection scheme. Maximum values determine the interrupting rating needed for circuit breakers, automatic circuit reclosers (ACRs), fuses, etc as well as the upper design limit for the protection scheme performance. Minimum current values determine the lower limit settings of overcurrent, earth fault relays and other protective devices to provide a satisfactorily high probability of detecting all faults. On a radial feeder, all protective devices between the substation relays and the fault measure the same current if the substation is the only source. This simplifies the coordination of overcurrent tripping devices to interrupt the fewest number of customers. Earth fault coordination may be affected if feeders have other sources of earth current. Sources of feeder fault current due to embedded generation may affect relay, fuse and ACR coordination, equipment rating, and safety of utility personnel and the general public. The magnitude of fault current from these sources will depend upon the type, size, and number of generators, their impedances, and their location with respect to the fault and utility substation. If the embedded generation contribution is large, the operation of the relays at the substation may be delayed due to a reduction in fault current from the source substation. A more likely case is that of a relatively high impedance embedded generation source located near the source substation. Such an <Check this is the latest version before use> Page 13 EX <Doc ID> Ver 1

19 arrangement contributes limited fault current until the utility circuit breaker opens, which may result in slow detection and sequential clearing of the fault. These multiple current source problems will apply to phase to earth faults if there is an earthed neutral (transformer or generator) at the faulted network voltage level. A fault study is essential for embedded generation proposals covering faults in the customer installation and the utility network. This should recognise the presence of other embedded generation installations that may be electrically nearby. The fault levels shall not exceed the embedded generator equipment rating. For the purposes of short term paralleling for network switching and load transfers the fault level may be allowed to exceed equipment rating. This exceedance needs to be considered on a case by case basis and be accompanied by a risk assessment. 7.8 Earthing High voltage generators shall have an earthing system that will not appreciably increase the distribution systems earth fault magnitude unless confirmation is provided by the DNSP that the increase in fault level is tolerable by the network. To accommodate this requirement the earthing arrangement at the interface between the DNSP and the Generator installation shall have (in order of preference): A solidly earthed network (that is confirmed to have no detrimental impact on the protection system or the safety of the distribution network) An impedance earthed network (that is confirmed to have no detrimental impact on the protection system or the safety of the distribution network) A network that may be earthed through operator control. Typically this earth will be applied through an isolator or high voltage switching device. The high voltage switching device would be controlled under an operating protocol. A network that is isolated from earth <Check this is the latest version before use> Page 14 EX <Doc ID> Ver 1

20 8 Explanation of the NER and Related Technical Requirements In general, the technical requirements for embedded generation in excess of 5MW can be derived from the requirements for systems less than 5MW, apart from where modified by Section 8 of this document. Where the following documents and Section 8 of this document are in conflict, then Section 8 of this document shall apply. The relevant standards are as follows: Energex 657 Customer Standard for Small to Medium Scale Embedded Generation (synchronous & asynchronous machines) Energex 233 Customer Standard for Parallel Generation via Inverter (for IES) Ergon Energy STNW Customer Standard for Small to Medium Scale Embedded Generation In the context of the DNSP s electricity network, Energex & Ergon Energy has the following requirements which are an interpretation of the NER access standards: 8.1 Reactive power capability Clause S of the NER describes the requirements of a Generator to provide reactive power at the point of connection over a range of power system conditions. Table 2 provides reactive power guidelines for which the DNSP will use to determine the level of access standard for the Generator. Table 2 Reactive power capability access Access Standard Automatic Minimum Negotiated Requirement The Generator must be capable of supplying and absorbing continuously at the connection point reactive power equal to x rated active power of the plant at any level of active power and at any voltage range of 90 to 110 per cent. No reactive power capability required. Reactive power capability as close as possible to the automatic standard. In order to determine the reactive power capability the Proponent needs to conduct steady state load flow studies at the connection point over a range of power system conditions. Typical operating voltage at the connection point and at the generation terminals and the tapping range of the transformers must be included in the studies. The studies need to demonstrate that the Generator can provide the reactive power range over the range of the connection point voltage of 90 to 110 percent of nominal voltage. This could be demonstrated by a reactive power capability diagram which shows reactive capability from zero to 100 percent power output over a generation terminal voltage range of 90 to 110 percent of nominal voltage. <Check this is the latest version before use> Page 15 EX <Doc ID> Ver 1

21 Figure 2 Reactive power capability diagram The DNSP may consider a negotiated standard in cases where the connection point is in a lightly loaded area and compliance with voltage standards will be achieved; or where the active power output may improve reactive power margins on the network without additional reactive power capability. Any such negotiation is dependent on the network at the connection point. If the generating system is used to provide support to the network the DNSP may require the Generator to provide additional reactive power capability but this will depend on the circumstances of each connection. The access standard regarding appropriate control strategies for operation within the reactive power capability range are addressed in section Quality of electricity generated Clause S of the NER requires the quality of the electricity generated by a Generator at the connection point to not have any detrimental effects on other customers. The Generator must not produce at the connection point voltage fluctuation, harmonic voltage distortion and voltage unbalance greater than the limits specified in the clause. Table 3 provides quality of supply guidelines for which the DNSP will use to determine the level of access standard for the Generator. Table 3 Quality of Supply access Access Standard Automatic Minimum Negotiated Requirement Generating system does not produce amounts of voltage fluctuation and harmonics greater than the limits allocated to the Generator by the DNSP. The voltage unbalance factor must not exceed the limits specified by the NSP. Generating system does not produce amounts of voltage fluctuation and harmonics greater than the limits (less onerous than for automatic access) allocated to the Generator by the DNSP. The voltage unbalance factor must not exceed the limits specified in Table S5.1a.1 of the NER. Limits to ensure the DNSP can meet its contractual obligations to existing users. The NER requires under a normal power system condition that the voltage at the connection point must not vary by more than ±10 per cent of its normal voltage, provided that the reactive power flow and the <Check this is the latest version before use> Page 16 EX <Doc ID> Ver 1

22 power factor (pf) at the connection point is within the limits as specified in the Generator Connection Agreement. However, as a result of a contingency event the voltage at the connection point must comply with Figure S5.1a.1. of the NER. Voltage fluctuation (flicker, rapid voltage change) shall be within limits stipulated by derogation clause Further information regarding the system compatibility and planning limits that the DNSP uses to derive limits for a specific connection are derived from this. Additional details on the requirements for the power quality of electricity generated may be found in the Standard for Network Performance (Energex standard or Ergon Energy standard STMP001). If the DNSP accepts a negotiated access standard the Generator may be required to upgrade to the automatic access standard where the DNSP connects new customers to its network. This is required to ensure the DNSP complies with the access standards defined in the NER. 8.3 Response to Frequency Disturbances Clause S requires the generating system to ride through frequency disturbances at the connection point and remain connected for the range of frequencies as outlined in this clause. Table 4 provides power frequency disturbance guidelines for which the DNSP will use to determine the level of access standard for the Generator. Table 4 Power frequency disturbance access Access Standard Requirement Automatic Continuous uninterrupted operation within the given ranges in accordance with Figure 3 Automatic Access Minimum Negotiated Continuous uninterrupted operation within the given ranges with reduced timing and in accordance with Figure 3 Automatic Access. Operation as close to the Automatic requirement without impacting on quality of supply. <Check this is the latest version before use> Page 17 EX <Doc ID> Ver 1

23 Figure 3 Frequency Disturbance Response The Generator shall provide details of the over and under frequency protection, steady state frequency range operating capability and maximum rate of change of frequency operating capability. 8.4 Response to voltage disturbances Clause S requires the Generator to ride through and remain connected for voltage disturbances at the connection point. Table 5 provides voltage disturbance guidelines for which the DNSP will use to determine the level of access standard for the Generator. Table 5 Response to voltage disturbance access Access Standard Requirement Automatic Continuous uninterrupted operation within the ranges given in Figure 4 and Figure 5. Minimum Negotiated Continuous uninterrupted operation within a range of ±10 per cent of normal voltage provided the voltage to frequency ratio is above specified limits. Operation as close to the Automatic requirement without impacting on plant safety, loss of generated power not greater than 100MW if the automatic access standard were applied, and no adverse impact on the quality of supply or power system security. <Check this is the latest version before use> Page 18 EX <Doc ID> Ver 1

24 Figure 4 Response to a voltage disturbance over 110% (automatic access) Figure 5 Response to a voltage disturbance under 110% (automatic access) <Check this is the latest version before use> Page 19 EX <Doc ID> Ver 1

25 Figure 6 Response to voltage-frequency disturbances The Generator must provide: Details of over and under voltage protection and their settings/limits; A curve (similar to Figure S5.1a.1 of the NER) which shows the range of voltages the Generator can ride through and remain connected for that range; and Details of the Generator s voltage operating capability. Note the generator terminal voltage and the Connection Point voltage may not necessarily be the same. The Network Technical Study must demonstrate that the Connection Point voltage requirements can be complied with for the settings applied at the generating system. The DNSP requires protection in place to trip the generating system where all three line to line voltages are below 0.85 p.u and the plant is absorbing inductive reactive power. This is to prevent the Generator from impeding network voltage recovery after a fault. The ranges detailed as part of the automatic and minimum access standard are also subject to the requirement that the Generator does not cause nearby LV networks to be outside the range of ±6 percent. <Check this is the latest version before use> Page 20 EX <Doc ID> Ver 1

26 8.5 Response to disturbances following contingency events Clause S of NER requires the Generator to remain in continuous uninterrupted operation through credible contingency events and network faults described in Table 6. Table 6 Credible Contingency Events and Network Faults Access Standard Automatic Minimum Negotiated Requirement For faults on a transmission network, three phase fault cleared by primary protection, phase to phase, two and single phase to ground faults as per the limits. For faults on a distribution network all faults cleared as per the limits. However, the event itself may disconnect the Generator from the network by removing the connection elements from service, otherwise the generating system must stay connected. The Generator is also required to provide a specified level of reactive power support during the fault and sufficient reactive power to maintain connection point voltage within a specified range with no significant reduction in active power after the fault. For a transmission or distribution network phase to phase, two and single phase to ground faults cleared by the longest relevant primary protection (ensuring there is no adverse impact on network security and generation loss limited to 100MW are not exceeded). However, the event itself may disconnect the Generator from the network by removing other network elements from service. The Generator is also required to provide sufficient reactive power to maintain connection point voltage within a specified range with no significant reduction in active power after the fault. As agreed with DNSP and AEMO in consideration of existing network constraints. The plant must not trip other connected loads and Generators as a result of an event for which they would otherwise not have tripped. The proponent must conduct time domain dynamic studies showing the Generator s capability to remain connected for the range of faults described in this clause. The studies should cover a range of operating conditions such as but not limited to the following: Maximum power generation at various levels of operating power factor conditions; Light, medium and high regional demands; and High and low level of interconnector transfer conditions. Fault simulation studies shall also demonstrate the following: For each drop of 1 per cent of the voltage at the connection point the Generator should supply a reactive current equal to 4 per cent of the maximum continuous current; and 95 per cent of the pre-fault active output is achieved within 100 metres of fault clearance. Operational arrangements such as control settings for the generating system s terminal voltage or transformer tap changers must meet the agreed level of performance. 8.6 Quality of electricity generated and continuous uninterrupted operation Clause S of the NER requires the Generator to remain connected for the specified values of voltage fluctuation, harmonic voltage distortion and voltage unbalance at the connection point. Table 7 provides guidelines for which the DNSP will use to determine the level of access standard for the Generator. <Check this is the latest version before use> Page 21 EX <Doc ID> Ver 1