HPC-9DJ

Transcription

1 Manual: Distribution Design Manual Volume 1 Quality of Electricity Supply Standard Number: HPC-5DC

2 Document Control Author Name: Anthony Seneviratne Position: Senior Standards Engineer Document Owner (May also be the Process Owner) Name: Justin Murphy Position: Manager Asset & Works Approved By * Name: Justin Murphy Position: Manager Asset & Works Date Created/Last Updated April 2013 Review Frequency ** 3 yearly Next Review Date ** April 2016 * Shall be the Process Owner and is the person assigned authority and responsibility for managing the whole process, end-to-end, which may extend across more than one division and/or functions, in order to deliver agreed business results. ** Frequency period is dependent upon circumstances maximum is 5 years from last issue, review, or revision whichever is the latest. If left blank, the default shall be 1 year unless otherwise specified. Revision Control Revision Date Description 0 22/01/2013 Initial Document Manager Assets and Works Asset & Works Framework Manager Senior Asset Strategy Engineer STAKEHOLDERS The following positions shall be consulted if an update or review is required: Manager Engineering Services Manager Engineering Standards DM# Page 2 of 39 Print Date 4/05/2017

3 CONTENTS FOREWORD 5 PREFACE 5 PART 1 STATEMENT TO CUSTOMERS 6 1. INTRODUCTION 7 2. ELECTRICITY SUPPLY QUALITY Frequency Voltage Levels Steady State Low Voltage Steady State Medium and High Voltage Voltage Fluctuations - Flicker Transient Impulses Harmonics Voltage Unbalance ELECTRICITY SUPPLY RELIABILITY Planned Supply Interruptions Unplanned Supply Interruptions CUSTOMER S RESPONSIBILITIES General Using Equipment from Outside Australia Purchasing Sensitive Equipment Protection of Sensitive Equipment Special Circumstances Customers with Disturbing Loads Insurance and Warranty MANUFACTURER S RESPONSIBILITIES CLAIMS AGAINST HORIZON POWER 20 PART 2 TECHNICAL REQUIREMENTS TECHNICAL REQUIREMENTS DISTURBING LOADS NOTIFICATION OF DISTURBING LOADS COMPLIANCE WITH TECHNICAL RULES POINT OF SUPPLY General Examples VOLTAGE FLUCTUATION HARMONIC DISTORTION POWER FACTOR VOLTAGE UNBALANCE 30 DM# Page 3 of 39 Print Date 4/05/2017

4 16. SYSTEM FREQUENCY ELECTROMAGNETIC INTERFERENCE ELECTRICAL INTERFERENCE RELEVANT STANDARDS AND PUBLICATIONS Horizon Power Publications External Publications Order of Precedence APPLICATION OF HORIZON POWERS STANDARDS Test/Measurement Times Voltage Fluctuation Harmonic Distortion Background Harmonic Voltage Distortion Parallel and Series Resonance Measurement standards Power Factor Voltage Imbalance Factor (VIF) Background Voltage Imbalance Measurement Times System Frequency Electromagnetic Interference REVISION INFORMATION 39 DM# Page 4 of 39 Print Date 4/05/2017

5 FOREWORD This manual, comprising a series of five volumes, covers the essential aspects of distribution engineering for Horizon Power. The reader must observe the standards and use the methods outlined in this volume of the Distribution Design Manual (DDM). If the reader believes that changes or additions are required to the manual, they must be submitted to the Engineering Standards Manager for consideration. Assistance in interpretation and use of the manual can also be obtained from the Horizon Power Engineering Standards Team. PREFACE About the Manual The five volumes forming part of this manual are: Volume 1: Quality of Electricity Supply Volume 2: Low Voltage Aerial Bundled Cable Volume 3: Supply to Large Customer Installations Volume 4: Underground Residential Distribution (URD) Volume 5: Overhead Bare Conductor Distribution The DDM serves to establish "standards" for design work to get the best value for money - not only in terms of initial cost, but also in terms of component availability, length of service life and cost-effective maintenance. In addition to this, the DDM will also serve as a teaching aid for courses run by Horizon Power. About Volume 1 This volume describes the standards related to the quality of Horizon Power s electricity supply. The volume is divided into two parts: Part 1: Statement to Customers Part 2: Technical Requirements Part 1 describes the quality and reliability of the electricity supply that customers can expect from Horizon Power. Part 2 describes the quality of supply technical requirements applicable to all customers with equipment connected to Horizon Power s electricity supply system. Part 2 is primarily aimed at Horizon Power s larger customers and indicates the technical limits which may be incorporated into electricity supply contracts for major customers. DM# Page 5 of 39 Print Date 4/05/2017

6 PART 1 STATEMENT TO CUSTOMERS DM# Page 6 of 39 Print Date 4/05/2017

7 1. INTRODUCTION Horizon Power is the principal supplier of electricity in Western Australia, outside of the South West Interconnected System (SWIS) The areas and towns that Horizon Power servers can be found via the following link: Horizon Power aims to comply with all applicable state and federal legislative instruments associated with the supply of electricity. Horizon Power is committed to providing its customers with a safe, reliable and high quality electricity supply at an economical price. Horizon Power will, so far as reasonably practicable, make every effort to provide its customers with a quality electricity supply within the limits expressed in this document. Further information regarding Horizon Power s electricity supply obligations can be obtained from Horizon Power s Technical Rules. References to other standards and other documentation are also specified as required. DM# Page 7 of 39 Print Date 4/05/2017

8 2. ELECTRICITY SUPPLY QUALITY Horizon Power aims to provide its customers with a regulated electricity supply within the following limits: 2.1 Frequency Horizon Power's nominal frequency has a legislative obligation according to the WA Electricity Act (1945) section (25(1)(d)) of 50 Hz ± 1.25 Hz The following table provides the frequency tolerances for normal operation of Horizon Power s systems and the frequency limits following a disturbance. Table 1: Frequency Operating Standards System Normal Operation Frequency following disturbance North West Interconnected System (NWIS) Non-Interconnected (Isolated) Systems to Hz 48 to 52 Hz to Hz 45 to 55 Hz Load shedding facilities are in place to ensure that the above frequency levels are not exceeded. For further information on frequency changes in Horizon Power s electricity system, refer to the Technical Rules. (HPC -9DJ ) 2.2 Voltage Levels Horizon Power provides its customers with several options of supply voltage levels. The level is dependent on the customer's load demand, load type, network considerations, geographic location and the required reliability of supply. Three broad voltage levels are available: Low Voltage Medium Voltage High Voltage Steady State Low Voltage Low Voltage is defined as steady state voltages less than 1 kv at the point of supply. The steady state value is defined as a 10 minute r.m.s value over one week in accordance with AS/NZS This general purpose electricity supply is provided via a three phase 240/415 V system. Residential and smaller commercial and industrial customers are typically supplied at Low Voltage. Horizon Power's nominal low voltage level is 240 V phase to neutral or 415 V phase to phase ± 6% under normal conditions, ±8%, under maintenance conditions and ± 10% under emergency conditions. DM# Page 8 of 39 Print Date 4/05/2017

9 Transient voltages may exceed the above limits, as described in section 2.5 Where more precise control of voltage is required by the customer, Horizon Power may accommodate the requirement in accordance with a specified connection agreement. For further information on voltage changes in Horizon Power s electricity network, refer to the Technical Rules. 2.3 Steady State Medium and High Voltage Medium Voltage is defined as steady state voltages equal to or greater than 1 kv and less than or equal to 35 kv, and High Voltage is defined as steady state voltages greater than 35 kv, at the point of supply. The steady state values are defined as phase to phase 10 minute r.m.s values measured over one week. (AS :2011) Commercial and industrial customers with large loads are usually supplied at Medium or High Voltage. Medium and High Voltage supplies are offered to the Customer at several different levels as described in the table below: Table 2: Medium and High Voltage Levels System Nominal Voltage Voltage Band Medium Voltage System High Voltage System 6.6 kv, 11 kv, 22 kv, 33 kv 66 kv, 132 kv, or 220 kv ± 10% of the nominal voltage ± 10% of the nominal voltage Transient voltages may exceed the above limits, as described in section 2.5 Medium and High Voltage customer supply contracts are usually negotiated on an individual basis and take into consideration the load demand, load type, network considerations, geographic location and the required reliability of supply. For further information on voltage changes in Horizon Power s electricity network, refer to the Technical Rules. 2.4 Voltage Fluctuations - Flicker Voltage fluctuations can be caused by the Customer or Horizon Power. On the customer s side, fluctuations typically occur as a result of the sudden application or disconnection of individual customer loads such as capacitor banks, motors, welding sets and furnaces. On Horizon Power s side, they can be caused by switching operations, lightning strikes, maintenance activities and equipment failures. Rapid voltage fluctuations cause changes to the luminance of lamps which can create the visual phenomenon called flicker. The voltage fluctuations which occur at the customers' Point of Supply shall be contained within the limits as set out in: AS/NZS :2002 Electromagnetic compatibility (EMC) - Limits - Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems - Equipment with rated current less than or equal to 75 A and subject to conditional connection DM# Page 9 of 39 Print Date 4/05/2017

10 AS/NZS :2006 Electromagnetic compatibility (EMC) - Limits - Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current ( 16 A per phase and not subject to conditional connection (IEC , Ed. 1.2(2005) MOD) AS/NZS :1998 Electromagnetic compatibility (EMC) - Limits - Limitation of voltage fluctuations and flicker in low-voltage power supply systems for equipment with rated current greater than 16 A Flicker is defined as rapid voltage fluctuations that cause changes to the luminance of lamps which can create the visual phenomenon called flicker. Flicker limits are defined in terms of the following parameters, as defined in AS/NZS :2012 Limits Assessment of emission limits for the connection of fluctuating installations to MV, HV and EHV power systems: Pst - short-term flicker severity term (obtained for each 10 minute period); PIt - long-term flicker severity (obtained for each 2 hour period). The legislated limits for short and long term flicker severity are defined in Part 2 (6(2)) of the Western Australian Electrical Industry Network Quality and Reliability of Supply Code Table 3: Legislated Flicker Severity Limits Parameter Compatibility Level Pst 1.0 PIt 0.8 Under normal operating conditions, flicker severity caused by voltage fluctuation in the transmission and distribution system shall be within the planning levels shown in the table below for 99% of the time. Table 4: Planning levels for flicker severity Parameter LV (415 V) MV ( 35 kv) HV-EHV (> 35 kv) Pst Plt Flicker severity shall be measured by a physical or virtual Flickermeter with the specifications defined in AS/NZS 61000: 4.15: Testing and measurement techniques Flickermeter Function and design specifications. Horizon Power s preferred software for performing flicker calculations at LV level is FlickPlus. Flicker calculations for loads to be connected at the MV and HV- EHV levels shall be carried out in accordance with HB 264:2003 Power Quality Recommendations for the application of AS/NZS and AS/NZS DM# Page 10 of 39 Print Date 4/05/2017

11 2.5 Transient Impulses Transient Impulses consist of sudden spikes, sags and surges in voltage. These are usually of very short duration but may last for several cycles or longer. A spike is a short duration excursion from the ideal or perfect sine wave shape, at the specified voltage and frequency. Sags and surges are decreases or increases of the peak value of the voltage waveform over several cycles or longer. Transient impulses occur on all electrical supply systems. The level of occurrence depends to a great extent on the nature of customer activity. Transient impulses are typically produced from within the customer's own installation and are therefore localised. On Horizon Power s side, they can be caused by switching operations, lightning strikes, switching operations, maintenance activities and equipment failures. Transient Impulses can cause severe disruptions to process-type industries by causing motor contactors to "trip out". Industrial control systems and modern electronic equipment can also be affected by transient impulses. Unprotected devices may be damaged as a result of transient impulses. Damage may also occur if the level of impulse protection is not sufficient to withstand the impulse magnitude or impulse type. Therefore, the care needs to be taken by the Customer in choosing suitable equipment that will minimise the risk of damage and interruption to plant operation. Refer to section 4 for the Customer s obligations in achieving protection against transient impulses. 2.6 Harmonics Harmonics are defined as sine wave components of a periodic waveform, having frequencies which are integer multiples of the periodic waveform's fundamental frequency. They are typically identified by software and instrumentation that is able to perform Fourier decomposition of waveforms. In electricity distribution systems, harmonics can cause the ideal or perfect voltage sine wave shape to be distorted. This may affect some sensitive communication systems and electronic equipment. Harmonics also contribute additional heating of motor and transformer windings and affect the overall efficiency of systems. Harmonics are often caused by industrial loads such as rectifiers, inverters and also by other non-linear customer loads such as welding sets, inverter air conditioners and electronic light dimmers. The ideal or perfect sine wave shape can be distorted to the extent that the resultant waveform is very different from the original waveform. Total Harmonic Distortion (THD) provides a measure of the amount of harmonics present in the supply system. The legislated limits for harmonic distortion are defined in Part 2 (7) of the Western Australian Electrical Industry Network Quality and Reliability of Supply Code 2005 and are summarised in the table below. DM# Page 11 of 39 Print Date 4/05/2017

12 Table 5: Legislated compatibility levels for harmonic voltages Compatibility levels for harmonic voltages (in percent of the nominal voltage) Odd harmonics non multiple of 3 Odd harmonics multiple of 3 Even harmonics Order h Harmonic voltage % Order h Harmonic voltage % Order h Harmonic voltage % > > > (25/h) Note Total harmonic distortion (THD): 8% Horizon Power does not provide planning limits that differ from the stated legislative limits. DM# Page 12 of 39 Print Date 4/05/2017

13 Table 6: Planning levels for harmonic voltages Planning levels for harmonic voltages (in percent of the nominal voltage) Odd harmonics non multiple of 3 Odd harmonics multiple of 3 Even harmonics Order h Harmonic voltage % Order h Harmonic voltage % Order h Harmonic voltage % > > > h Note: Total harmonic distortion (THD): 6.5 % The contribution of a Customer s level of harmonics may be assessed by direct measurement or by calculation from the available data for the load and the power system. The measurement must be carried out according to AS/NZS :1999. Harmonics must generally be measured up to h=40. However, higher order harmonics up to 100th order may also be measured. Harmonics calculations for loads to be connected at the MV and HV-EHV levels shall be carried out in accordance with HB 264:2003 Power Quality Recommendations for the application of AS/NZS and AS/NZS Voltage Unbalance Most residential customers are provided with single phase 240 V supplies from Horizon Power's three phase 240/415 V system. Larger residential customers and generally all commercial and industrial customers on the other hand are provided with three phase supplies. The conditions for which customers require a three phase low voltage connection are specified in the Western Australian Distribution Connections Manual (May 2012) The voltage levels supplied on each of the three phases are generally of the same peak value (or magnitude). In practice, however, some imbalance between the individual peak voltage magnitudes on the three phases can occur. The DM# Page 13 of 39 Print Date 4/05/2017

14 Voltage Imbalance Factor provides a measure of the amount of imbalance between the voltage magnitudes on the three phases. The customer shall not cause the voltage unbalance factor at the Point of Supply (measured in terms of percentage of negative sequence voltage to positive sequence voltage) to exceed the limits in Table 7. Table 7: Limits for negative phase sequence component of voltage (in percent of the positive phase sequence component) Nominal System Voltage Negative Sequence Voltage (%) > 100 kv kv 1.5 < 10 kv 2 The Voltage Unbalance Factor is defined separately for different supply voltage levels. Refer to Part 2 Section 15 for more information on how voltage unbalance is calculated. 3. ELECTRICITY SUPPLY RELIABILITY Horizon Power provides a general purpose electricity supply. If a higher than normal level of reliability and availability is required at a particular installation, it must be negotiated on an individual basis and described in a supply contract. The reliability requirements shall take into account the customer's load size, load type, geographic location and network constraints as well as other requirements particular to the supply. Horizon Power is constantly striving to improve the reliability of supply to its customers in accordance with targets set by the Economic Regulation Authority (ERA). Horizon Power endeavours to provide its customers with a continuous supply of electricity. Supply to some customers may have to be disconnected on occasions for planned maintenance and system alteration activities. At other times, factors outside Horizon Power's control may also cause outages resulting in loss of supply to customers. Common causes of outages vary but include equipment failure, lightning strikes, network faults, weather events, maintenance activities and traffic accidents. Horizon Power is obligated under legislation to meet specific reliability levels. The main legislative instrument stipulating this is the Western Australian Electrical Industry Network Quality and Reliability of Supply Code Sections 3.1 and 3.2 below describe the legislative and other determinants of the reliability of Horizon Power s Network. 3.1 Planned Supply Interruptions To maintain the level of reliability and performance expectations, various items of electrical plant which make up the supply system must be maintained on a regular basis. System alterations are carried out to connect new customers to the system or to improve the quality of supply to existing customers. DM# Page 14 of 39 Print Date 4/05/2017

15 During these activities, supply may be interrupted for the duration of the work. If possible, Horizon Power will provide backup supplies but only to the capacity limit of the existing system. Horizon Power will not provide alternative temporary backup supplies such as mobile generators, etc. The Western Australian Electrical Industry Network Quality and Reliability of Supply Code 2005 specifies the limits for planned interruption duration and compensation, and is summarised below: Wherever possible, Horizon Power will plan all non-urgent supply interruptions so that customers are fully informed of the intended interruption at least 72 hours prior to the commencement of work. Horizon Power endeavours to notify its domestic customers whose supplies will be interrupted, by card, delivered to their letter boxes at least 72 hours prior to the work being carried out. The card contains information on the supply interruption time, duration, etc. For shutdowns affecting a larger number of customers, an official advertisement will be placed in the appropriate local newspaper both 5 days and 3 days prior to the event, wherever practicable. Announcements on local radio stations may also be used in some instances. Wherever possible, Planned Supply Interruptions in residential areas are generally restricted to: South of the 26 th parallel of latitude: i. 6 hours; or ii. 4 hours, if at the time when notice is given the forecast maximum temperature issued by the Bureau of Meteorology for the area in which the premises are situated is 30 C or more for any part of the period of the interruption; North of the 26 th parallel of latitude, planned supply interruptions are limited to 4 hours. Shutdowns affecting large commercial and industrial customers, heavy industry, process industry or mining operations are negotiated on an individual basis, if possible. Wherever practicable, shutdowns are planned to take place at times which will cause minimal disruption to normal business activities. 3.2 Unplanned Supply Interruptions There are many factors which can affect the supply arrangement to an installation. These factors, which can collectively be referred to as "design considerations", include: 1. Customer's load (i.e. size and estimate of, growth, nature, permanency); 2. "Disturbing Loads" and containment within Horizon Power's Quality of Supply limits; 3. Customer's Supply Reliability requirements; 4. Available "surplus" capacity in existing system; 5. Demand side initiatives if any; DM# Page 15 of 39 Print Date 4/05/2017

16 6. Embedded generation options; 7. System Design/Strategy/Operation considerations in particular load area such as undergrounding; 8. Economics of different supply options, etc. These design considerations are discussed in more detail in the following sections. DM# Page 16 of 39 Print Date 4/05/2017

17 4. CUSTOMER S RESPONSIBILITIES 4.1 General Customers are responsible to ensure that the equipment they intend to use is correctly rated for Horizon Power's supply voltage and that it has a tolerance suited to Horizon Power's supply limits. If there is any doubt, customers should refer to the instruction manual or product information guide for the equipment, the manufacturer or retailer, their electrical contractor or electrical consultant. 4.2 Using Equipment from Outside Australia Customers intending to purchase or use equipment manufactured from outside Australia on Horizon Power's supply system should first confirm with the manufacturer or retailer that the equipment complies with the minimum requirements of applicable Australian Standards. International Electrotechnical Commission (lec) standards are generally compatible with similar Australian standards. Equipment with appropriate Underwriter Laboratory certification, NATA laboratory certification or other third party certification are also looked upon favourably. Customers intending to procure or use equipment manufactured from outside Australia on Horizon Power s supply system should first confirm with the manufacturer or retailer that the equipment complies with minimum requirement of applicable Australian Standards. 4.3 Purchasing Sensitive Equipment Computers, microwave ovens, stereos and similar electronic equipment can be susceptible to damage caused by Transient Impulses and Voltage Fluctuations in the power supply. Customers intending to purchase this type of equipment mould first confirm with the manufacturer or retailer that it is capable of satisfactory operation on Horizon Power's system without additional protection. The technical rules (awaiting publication) specify the contractual requirements of Horizon Power. Together with applicable legislation, this provides performance limits of the electricity system. Reliability surveys and third party certification may also provide assistance in choosing the most suitable equipment. 4.4 Protection of Sensitive Equipment Customer with sensitive or expensive electrical or electronic equipment which is incapable of satisfactory operation on Horizon Power's system without additional protection are advised to install appropriate, voltage conditioning devices. This will reduce the risk of damage from any voltage variations in the power supply. Depending on the customer's needs and the equipment to be protected, a power line conditioner or a voltage regulator may suffice. 4.5 Special Circumstances Customers who have: DM# Page 17 of 39 Print Date 4/05/2017

18 1. installations where momentary or prolonged loss of supply would cause damage to equipment or food, loss of revenue, jeopardise health; safety or-security; or 2. installations susceptible to damage caused by Transient Impulses, high or low voltage levels, voltage imbalance levels or harmonic levels, etc., should seek advice from Horizon Power or an electrical consultant on the need to install additional equipment to minimise disturbances (e.g. Uninterruptible Power Supply (UPS), undervoltage motor protection, powerline conditioners, harmonic filters). This would typically apply for customers with critical plant processes, large computer or control, system, medical equipment (including home dialysis machines), bulk cold food storage, etc. Customers with plant processes susceptible to "trip outs" caused by voltage depressions during faults should consider installing time delays on undervoltage relays to "ride through" the depressed voltage period (typically lasting up to 500 milliseconds with 'voltage depressions of around 20 percent of nominal levels). d.c or latched contactors should also be considered where motor drives aft required to operate continuously. 4.6 Customers with Disturbing Loads Customers intending to install electrical or electronic equipment which is likely to cause unwanted disturbances on Horizon Power's supply system must inform Horizon Power prior to installation. Examples of disturbing loads include: power converters (e.g. rectifiers, inverters, variable motor speed drives); arcing devices (e.g. arc furnaces, discharge lamps, welding devices); magnetic core equipment (e.g. voltage regulating transformers, large motors); power factor correcting equipment (e.g. capacitors, reactors). Horizon Power will advise on any remedial action required before installation and/or negotiate a special agreement for the supply. This requirement applies to larger residential customers, all commercial and industrial customers. 4.7 Insurance and Warranty Most insurance companies provide cover against damage to electrical and electronic equipment due to storms, fires and motor fusion. Customers are advised to check the extent of cover in their individual policies. As an alternative, some electronics repair companies can also provide insurance cover for equipment. Customers are also advised to check the conditions of the manufacturer's warranty when purchasing new equipment (e.g. with some computer or business equipment, the warranty is only valid if the power to the equipment is provided via an approved powerline conditioner). DM# Page 18 of 39 Print Date 4/05/2017

19 5. MANUFACTURER S RESPONSIBILITIES Manufacturers and retailers of equipment intended for the Australian market should ensure that they and the equipment conforms with all the relevant requirements of the Consumer Competition Act, Corporations Act, Fair Trading Act, the Electricity Act Regulations and applicable Australian Standards. Electrical or electronic equipment falling within the prescribed list of items requiring testing and approval by a recognised Australian Electricity Authority must bear an approvals number. Manufacturers or retailers of electrical or electronic equipment which may be susceptible to damage caused by voltage variations and transient impulses nominally encountered in the supply system should inform prospective buyers of the requirement for further protection. DM# Page 19 of 39 Print Date 4/05/2017

20 6. CLAIMS AGAINST HORIZON POWER In general, Horizon Power is not liable for any damage to customers' equipment or consequential loss if: 1. there has been no negligence on Horizon Power's part; or 2. the damage or loss was caused by: events or circumstances which are beyond its control (storms, vandalism, industrial disputes, etc.); or the equipment itself (defective, inability to provide the performance or safety which persons are generally entitled 10 expect, non-conformance with recognised standards, etc.); or the misuse of the equipment, wear and tear, improper installation, etc. If Horizon Power is liable, then Horizon Power will assist the customer in meeting the costs of repair. DM# Page 20 of 39 Print Date 4/05/2017

21 PART 2 TECHNICAL REQUIREMENTS DM# Page 21 of 39 Print Date 4/05/2017

22 7. TECHNICAL REQUIREMENTS Horizon Power requires that all customers' electrical installations and the operation of equipment, comply with Horizon Power's Quality of Supply Technical Requirements laid out in this volume. This is to ensure that the quality of supply to all other customers can be maintained within acceptable standards (see note below). This document details the technical limits that Horizon Power applies to customers' installations and equipment. It also lists examples of equipment which have the potential to disturb or degrade the electricity supply. Customers intending to install such equipment must consult Horizon Power before connecting the equipment to the supply. The quality and reliability of electricity supply that customers can expect from Horizon Power is defined in Part 1. DM# Page 22 of 39 Print Date 4/05/2017

23 8. DISTURBING LOADS Some electrical loads can adversely affect the quality of electricity supply they are connected to and ultimately the performance of other equipment. These are termed Disturbing Loads. Examples of such loads are: Power Converters (e.g. rectifiers. inverters, variable speed motor drives); Arcing Devices (e.g. arc furnaces, discharge lamps, welding equipment); Magnetic Core Equipment (e.g. voltage regulating transformers, large motors, induction furnaces); and Power Factor Correcting Equipment (e.g. capacitors. reactors). The level of disturbance such equipment may cause depends on several factors. These are the size and characteristics of the equipment, the point of connection on the supply network and other equipment connected to the supply system. DM# Page 23 of 39 Print Date 4/05/2017

24 9. NOTIFICATION OF DISTURBING LOADS Customers intending to install potentially disturbing loads are encouraged to consult Horizon Power as early as possible in their planning and purchasing stages. In any case, they must not connect the proposed equipment to the supply system prior to consulting Horizon Power. For each proposal, Horizon Power will; require specific technical information from the customer about the operation of the proposed equipment. and studies or calculations carried out by the equipment's manufacturer or the customer's electrical consultant demonstrating that the equipment could comply with the Technical Requirements; Upon request provide background levels of disturbances at a point on the system, closest to the proposed installation, to enable the customer or his electrical consultant to carry out the studies and calculations. Horizon Power may charge a nominal fee for this service; carry out its own assessment of the equipment's potential to cause disturbances, and the likely level of disturbance; and advise the customer in writing of the conditions under which the proposed equipment can be connected to the supply system. For some disturbing loads, Horizon Power may negotiate a special supply agreement with the customer, which will stipulate the limits and conditions for connection). Horizon Power will decide whether the proposed equipment is suitable for connection to the supply system based on its effect on: Voltage Fluctuation; Harmonic Distortion (Voltage and Current); Direct Current (D.C.) components; Power Factor; Voltage Imbalance; Electrical Interference; and Other Harmful Effects. From the information supplied by the customer, if the level of potential disturbance exceeds the maximum allowable limits, Horizon Power will advise the customer of the need for additional countermeasures to reduce the level of disturbances, e.g. harmonic filters, soft-starters, etc. After the appropriate work has been carried out by the customer, Horizon Power will provide a Conditional Approval to the customer, which will allow the customer to connect the equipment and to carry out the necessary tests to prove compliance. DM# Page 24 of 39 Print Date 4/05/2017

25 10. COMPLIANCE WITH TECHNICAL RULES Horizon Power Technical Rules stipulate the mandatory compliance with interference free operation of customers' equipment. These mandatory compliance requirements ensure that the quality of supply to all customers can be maintained within acceptable standards. At all times, the customer shall be responsible for complying with Horizon Power's Technical Rules and shall bear the cost of all tests and studies carried out to provide proof of compliance, when requested by Horizon Power. Customers with potentially disturbing loads must ensure that the installation and operation of their equipment complies with the Technical Rules and the limits stipulated in any special supply agreement. If there is any doubt, Horizon Power will require the customer to provide proof of compliance, e.g. from tests or studies carried out. Horizon Power will maintain a log of all Quality of Supply complaints and, if it receives a significant number, will investigate and identify the sources of the disturbances; Horizon Power may also require some customers to log the operation of all potentially disturbing loads in the installation over a predefined period. Customers whose equipment causes disturbances outside limits on the supply system shall be responsible for modifying the equipment or its operation within a reasonable time agreed with Horizon Power. This includes modifications to ensure compliance with the Technical Rules following changes to an equipment's operating conditions. DM# Page 25 of 39 Print Date 4/05/2017

26 11. POINT OF SUPPLY 11.1 General The Point of Supply is the location at which the customer s mains are connected to Horizon Power s network. It is the connection point on the network supplying the customer, at which the Technical Rules apply. At all times, Horizon Power will nominate the Point of Supply, and may take into account future customer connections and developments of the system. If the customer is supplied from more than one point on the supply system, each point will be treated separately and the customer is required to comply with the requirements at each point. Horizon Power will also specify fault level and other data required for voltage fluctuation studies together with the system outage conditions on which the values are based. If a Sole Use substation is established for a single customer supplied at low voltage, the installation must be clearly identified as being Sole Use, so that no other customer is supplied from the LV side of the transformer in the future. All applications for supply at transmission voltages will be individually assessed by Horizon Power Examples The POS for an installation is dependent on the supply arrangement and voltage level, For example, the POS of a MV or HV supplied customer is normally taken to be at the supply (line) side of the MV or HV isolator. The POS of a LV supplied customer on the other hand is dependent on whether the supply is via overhead conductors or underground cable. If supplied from a District substation, the POS is normally taken to be at the supply (line) side of the customer's metering point, while with a sole Use substation arrangement, the POS is normally taken to be at the distribution transformer's MV terminals. The WA Electrical Requirements document and Horizon Power's Distribution Design Manual - Volume 3: Supply to Large Customer Installations provide further information on supply arrangements and should be referred to. DM# Page 26 of 39 Print Date 4/05/2017

27 12. VOLTAGE FLUCTUATION Voltage Fluctuations occur because of the sudden connection or disconnection of individual customer loads. Voltage Fluctuations can be minimised using several methods. Examples of these are special starting devices for motors, installing capacitors and restricting the operating times of equipment. The Voltage Fluctuation limits imposed by Horizon Power are in accordance with the limits set out in: AS/NZS :2002 Electromagnetic compatibility (EMC) - Limits - Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems - Equipment with rated current less than or equal to 75 A and subject to conditional connection AS/NZS :2006 Electromagnetic compatibility (EMC) - Limits - Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current ( 16 A per phase and not subject to conditional connection (IEC , Ed. 1.2(2005) MOD) AS/NZS :1998 Electromagnetic compatibility (EMC) - Limits - Limitation of voltage fluctuations and flicker in low-voltage power supply systems for equipment with rated current greater than 16 A DM# Page 27 of 39 Print Date 4/05/2017

28 13. HARMONIC DISTORTION Non-linear, industrial loads generally produce harmonics on the supply system. Examples of these are rectifiers, inverters, variable speed motor drives and power factor correcting equipment. Harmonics can distort the ideal or perfect voltage sine wave shape and may affect sensitive communication systems and electronic equipment. Horizon Power's Harmonic Distortion limit requirements are as detailed in: AS :2007 Electromagnetic compatibility (EMC) - Limits - Limits for harmonic current emissions (equipment input current (16 A per phase) AS :2007 Electromagnetic compatibility (EMC) - Limits - Limitation of emission of harmonic currents in low-voltage power supply systems for equipment with rated current greater than 75 A AS :2006 Electromagnetic compatibility (EMC) - Limits - Limits for harmonic currents produced by equipment connected to public low-voltage systems with input current >16 A and 75 A per phase AS :2001 Electromagnetic compatibility (EMC) - Limits - Assessment of emission limits for distorting loads in MV and HV power systems DM# Page 28 of 39 Print Date 4/05/2017

29 14. POWER FACTOR The customer's power factor requirement is dependent on the location of the customer's Point of Supply. The required value will be individually assessed. In most cases an allowable power factor range will be specified. For example, the customer's power factor may be required to be between 0.95 lagging and 0.95 leading. The minimum power factor requirement that Horizon Power may specify is 0.8 lagging to 0.8 leading. NOTE: The specified power factor range applies to the continuous load. The restraint is relaxed for transient periods when, for example, motors are being started. DM# Page 29 of 39 Print Date 4/05/2017

30 15. VOLTAGE UNBALANCE Single phase loads, unbalanced three phase loads and semiconductor based devices can cause voltage imbalances in Horizon Power's supply system. Voltage Unbalance can cause overheating of synchronous and asynchronous motors and affect the output d.c. voltage of rectifiers. Voltage unbalance restrictions are typically only applied to customers connected at a supply voltage of 6.6 kv, or greater. The Voltage Unbalance Factor (V uf ) is defined as: V uf = (V NPS -V PPS) x 100% where: V NPS - Negative Phase Sequence component of voltage V PPS - Positive Phase Sequence component of voltage The Voltage Unbalance Factor must be determined accurately for Transmission Voltage levels (> 35 kv). Appropriate measuring/analysis methods shall be used to determine V NPS and V PPS. At Distribution Voltage levels (< 35 kv), the following simpler Voltage Imbalance Factor definition may be applied: V IF = (Max ΔV / Avg.V) x 100% where: Avg, V is the numerical average of the three individual phase-to-phase voltage values (measured simultaneously); and Max ΔV is the maximum difference between any of the three phase-tophase voltage values (measured simultaneously) and Avg.V The customer shall not cause the voltage unbalance factor at the Point of Supply (measured in terms of percentage of negative sequence voltage to positive sequence voltage) to exceed the limits in Table 9. Table 9: Limits for negative phase sequence component of voltage (in percent of the positive phase sequence component) Nominal System Voltage Negative Sequence Voltage (%) > 100 kv kv 1.5 < 10 kv 2 DM# Page 30 of 39 Print Date 4/05/2017

31 16. SYSTEM FREQUENCY The customer load limitations associated with system frequency fluctuations are typically only applied to customers connected at a supply voltage of 35 kv or greater, or on small isolated supply systems with diesel generators. In most cases, the impact on system frequency of customer load fluctuations is negligible. However, in some cases, Horizon Power may impose a limitation on the maximum permissible step load change or rate of load change. Where this is necessary, the limitation applicable will be based on an individual assessment. DM# Page 31 of 39 Print Date 4/05/2017

32 17. ELECTROMAGNETIC INTERFERENCE The limitation of electromagnetic interference shall meet the requirements listed in the following standards: AS/NZS :2000 Electromagnetic compatibility (EMC) General Application and interpretation of fundamental definitions and terms AS/NZS :2003 Electromagnetic compatibility (EMC) Environment Compatibility levels for low-frequency conducted disturbances and signalling in public medium-voltage power supply systems AS/NZS :2003 Electromagnetic compatibility (EMC) Environment Compatibility levels for low-frequency conducted disturbances and signalling in public lowvoltage power supply systems AS/NZS :2007 Electromagnetic compatibility (EMC) Generic standards Emission standard for residential, commercial and light-industrial environments AS/NZS :2007 Electromagnetic compatibility (EMC) Generic standards Emission standard for industrial environments DM# Page 32 of 39 Print Date 4/05/2017

33 18. ELECTRICAL INTERFERENCE Interference to a third party, such as could occur with radio frequency electrical interference or interference with telecommunication infrastructure would be regarded as sufficient cause to require a customer to take corrective action. DM# Page 33 of 39 Print Date 4/05/2017

34 19. RELEVANT STANDARDS AND PUBLICATIONS The information contained in this volume is derived from several technical documents and publications (both internal and external) Horizon Power Publications Horizon Power Technical Rules Horizon Power Distribution Design Manual Volume 3 Horizon Power Fit for Purpose Objectives - 22 October External Publications WA Electricity Act 1945 WA Electrical Industry (network quality and reliability of supply) code 2005 WA Distribution Connections Manual May 2012 WA Electrical Requirements AS/NZS :2002 Electromagnetic compatibility (EMC) - Limits - Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems - Equipment with rated current less than or equal to 75 A and subject to conditional connection AS/NZS :2006 Electromagnetic compatibility (EMC) - Limits - Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current (<=16 A per phase and not subject to conditional connection (IEC , Ed. 1.2(2005) MOD) AS/NZS :1998 Electromagnetic compatibility (EMC) - Limits - Limitation of voltage fluctuations and flicker in low-voltage power supply systems for equipment with rated current greater than 16 A AS :2007 Electromagnetic compatibility (EMC) - Limits - Limitation of emission of harmonic currents in low-voltage power supply systems for equipment with rated current greater than 75 A AS :2006 Electromagnetic compatibility (EMC) - Limits - Limits for harmonic currents produced by equipment connected to public low-voltage systems with input current >16 A and 75 A per phase AS :2001 Electromagnetic compatibility (EMC) - Limits - Assessment of emission limits for distorting loads in MV and HV power systems AS/NZS :2000 DM# Page 34 of 39 Print Date 4/05/2017

35 Electromagnetic compatibility (EMC) - General - Application and interpretation of fundamental definitions and terms AS/NZS :2003 Electromagnetic compatibility (EMC) - Environment - Compatibility levels for lowfrequency conducted disturbances and signalling in public medium-voltage power supply systems AS/NZS :2003 Electromagnetic compatibility (EMC) - Environment - Compatibility levels for lowfrequency conducted disturbances and signalling in public low-voltage power supply systems AS/NZS :200 Electromagnetic compatibility (EMC) - Generic standards - Emission standard for residential, commercial and light-industrial environments AS/NZS :2007 Electromagnetic compatibility (EMC) - Generic standards - Emission standard for industrial environments 19.3 Order of Precedence In the event of a conflict arising between the reference documents, the following order of precedence shall apply: Table 2: Order of Precedence Order Reference Document 1 Legislation 2 Horizon Power Documentation 3 Australian Standards 4 Other Documents The Customer shall notify Horizon Power of any such conflict prior to undertaking work in relation to this Document. DM# Page 35 of 39 Print Date 4/05/2017

36 20. APPLICATION OF HORIZON POWERS STANDARDS It is the customer's responsibility to comply with the Technical Requirements. If in doubt, the customer is required to provide proof of compliance. e.g. from tests or studies carried out. This section details the requirements under which the tests are carried out. Note: All measurements to assess compliance with the Technical Requirements are to be taken at the customer's Point of Supply Test/Measurement Times After the Conditional Approval has been given to the customer to connect up the equipment, the customer is required to carry out the tests and take the necessary measurements with the equipment connected, generally within 3 months after connection, to prove compliance. For some customers, Horizon Power may request a repeat of the tests after 12 months of initial proof of compliance to ensure continued compliance. At all times, the customer shall advise Horizon Power of any changes in the nature of their load, so that a revised assessment can be carried out. Horizon Power may request proof of compliance following the implementation of the revised operating conditions. Horizon Power may conduct occasional checks as pan of its Quality of Supply investigations. If a customer is found to no longer comply, the customer is required to carry out the necessary work and repeat the tests and measurements to provide proof of compliance Voltage Fluctuation The application of the voltage fluctuation limits is as per Section Harmonic Distortion Background Harmonic Voltage Distortion The percentage harmonic voltage distortion limits apply without including existing (background) harmonic voltage distortion. Because the harmonic voltage distortion cannot be measured without including the background distortion the following procedure is used: 1. Measure the background harmonic voltage distortion at the Point of Supply, without the customer connected. 2. Measure the harmonic voltage distortion at the Point of Supply, with the customer connected. 3. Apply the harmonic voltage distortion limits to the increase in the percentage distortion values at the Point of Supply Parallel and Series Resonance Due to parallel and series resonance, measurements shall be taken with local Horizon Power capacitors in and out of service, both with and without the DM# Page 36 of 39 Print Date 4/05/2017