Reasonableness Test RT 015 /11 Salisbury Substation 11kV Feeders

Reasonableness Test RT 015 /11 Salisbury Substation 11kV Feeders

Reasonableness Test: Salisbury Substation 11kV Feeders DISCLAIMER The purpose of this document is to inform customers, Interested Parties, Registered Participants and solution providers of the outcome of the application of the Reasonableness Test to the network constraint of overload of the Salisbury Substation 11kV Feeders. This document is not intended to be used for other purposes, such as making decisions to invest in generation, transmission or distribution capacity. This document has been prepared using information provided by, and reports prepared by, a number of third parties. While care was taken in the preparation of the information in this paper, and it is provided in good faith, ETSA Utilities accepts no responsibility or liability for any loss or damage that may be incurred by any person acting in reliance on this information or assumptions drawn from it. This Reasonableness Test has been prepared in accordance with section 3 of ESCOSA Guideline 12 Demand Management for Electricity Distribution Networks for the purpose of consulting with Registered Participants, Interested Parties and customers regarding a potential network augmentation. The Reasonableness Test has been prepared with consideration for pertinent information provided by a number of third parties. It contains assumptions regarding, among other things, economic growth and load forecasts that, by their nature, may or may not prove to be correct. ETSA Utilities advises that anyone proposing to use this information should verify its reliability, accuracy and completeness before committing to any course of action. ETSA Utilities makes no warranties or representations as to its reliability, accuracy and completeness and ETSA Utilities specifically disclaims any liability or responsibility for any errors or omissions or not. It is important to note that ETSA Utilities as Distribution Network Service (DNSP) provider can only consider benefits available to the DNSP in evaluating the viability of Demand Management initiatives, e.g. transmission benefits, the possibility of reducing spot market prices and wider benefits like reducing green house gasses have not been considered. Page 2 of 9

Reasonableness Test: Salisbury Substation 11kV Feeders GUIDELINE 12 REASONABLENESS TEST Salisbury Substation 11kV Feeders 1. CURRENT SUPPLY ARRANGEMENT The Salisbury Substation is part of the Northern Suburbs 66,000 V (66 kv) electricity distribution system. The substation is operated at 66 kv stepped down to 11 kv and has ten 11 kv feeder exits that supply the local residential and industrial load including Salisbury Plains (SA14), River (SA13) and Salisbury East (SA17) 11kV feeders. The forecast peak load of Salisbury Plains (SA14) in 2013/14 is 9.5MVA, which will exceed its normal supply capacity of 9.1MVA by 0.4MVA. In addition, up to 4.3MVA of load will be at risk of being unsupplied after load transfers to adjacent feeders for a loss of the Salisbury Plains 11kV feeder (SA14) during the summer 2013/14 peak load period. The forecast peak load of River (SA13) in 2013/14 is 9.3MVA, which will exceed its normal supply capacity of 9.1MVA by 0.2MVA. In addition, up to 3MVA of load will be at risk of being unsupplied after load transfers to adjacent feeders for a loss of the River 11kV feeder (SA13) during the summer 2013/14 peak load period. The forecast peak load of Salisbury East 11kV feeder (SA17) in 2013/14 is 9.2MVA, with up to 3.1MVA of load will be at risk of being unsupplied after load transfers to adjacent feeders for a loss of the Salisbury East 11kV feeder (SA13) during the summer 2013/14 peak load period. To cater for network risks and business needs, ETSA Utilities Network Planning criteria stipulates that feeders are reinforced when feeder load is forecast to exceed 110% of the normal rating limit or more than 1.9MVA of customer load is at risk following load transfers for a feeder outage at peak load times. A failure of Salisbury Plains, River or Salisbury East 11kV feeders will affect a large number of customers, resulting in a high Service Target Performance Incentive Scheme (STPIS) penalty. The overall supply arrangement of these feeders are shown in Figure 1. Page 3 of 9

Reasonableness Test: Salisbury Substation 11kV Feeders Figure 1: Salisbury Area Electricity Supply System Page 4 of 9

MVA MVA Reasonableness Test: Salisbury Substation 11kV Feeders 2. FORECAST LOAD AND CAPACITY Load at Salisbury Plains, River and Salisbury East feeder consists mainly of residential load. During hot weather in the summer months, residential air conditioning contributes a significant proportion to the peak load. The peak load is forecast to increase at a rate of approximately 1% per annum. The winter peak load is not expected to grow faster than the summer peak and has therefore been ignored. 14.0 Salisbury Plains 11kV Feeder - Load versus Capacity 12.0 10.0 8.0 6.0 4.0 2.0 0.0 2013/14 2014/15 2015/16 2016/17 Year Load Forecast Normal Capacity Offload Capability Emergency Capacity Figure 2: Load verses capacity of Salisbury Plains 11kV feeder (SA14). 14.0 River 11kV Feeder - Load versus Capacity 12.0 10.0 8.0 6.0 4.0 2.0 0.0 2013/14 2014/15 2015/16 2016/17 Year Load Forecast Normal Capacity Offload Capability Emergency Capacity Figure 3: Load verses capacity of River 11kV feeder (SA13). Page 5 of 9

MVA Reasonableness Test: Salisbury Substation 11kV Feeders 14.0 Salisbury East 11kV Feeder - Load versus Capacity 12.0 10.0 8.0 6.0 4.0 2.0 0.0 2013/14 2014/15 2015/16 2016/17 Year Load Forecast Normal Capacity Offload Capability Emergency Capacity Figure 4: Load verses capacity of Salisbury East 11kV feeder (SA17). Page 6 of 9

% of Load Load (A) Reasonableness Test: Salisbury Substation 11kV Feeders 3. LOAD CHARACTERISTICS The load duration curve (figure 6) shows that Salisbury Plains, River and Salisbury East feeders experience high loads for short periods during summer heat wave events. The peak load curves (figure 5), experienced on peak days show that high loads occur between 10am and 10pm, as could be expected for feeder with high levels of residential air-conditioning load. 100% Daily Load Curve - Salisbury Substation 11kV Feeders 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 Time of Day Salisbury Plains River Salisbury East Figure 5: Salisbury Substation 11 kv Feeders - Daily Load Curve Load Duration Curve - Salisbury Substation 11kV Feeders 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 0 10 20 30 40 50 60 70 80 90 100 Percentage of Time Salisbury Plains River Salisbury East Figure 6: Salisbury Substation 11kV Feeders - Load Duration for 2/10/2009 to 2/10/2010 Page 7 of 9

Reasonableness Test: Salisbury Substation 11kV Feeders 4. NETWORK UPGRADE OPTIONS Options that have been investigated to resolve all three N-1 constraints of the Salisbury Plains, River and Salisbury East 11kV feeders include the following: Design, install and commission a new 11kV feeder exit from the existing CB2143 at Elizabeth South Substation using 630mm 2 XLPE cable. Install approximately 2.9km of 630mm 2 XLPE cable together with spare telecommunication conduit from a new Mk7 transformer cubicle to an over/ under pole near A3756. Restring selected part of the new feeder backbone and ties. Design, install and commission a new 11kV feeder exit from the existing CB2000 at Salisbury Substation using 630mm 2 XLPE cable. Install approximately 3.7km of 630mm 2 XLPE cable together with spare telecommunication conduit from the 11kV switchboard to an over/under pole along Carlingford Drive. Restring a selected part of the new feeder backbone and ties. Preferred Network Solution The preferred solution, when the net present cost, timing and effectiveness of the related upgrade projects is considered, is to construct a new Salisbury Park 11kV feeder from Elizabeth South Substation. The indicative cost for this project is $2.2 Million. It is planned for completion in 2013. 5. DEMAND MANAGEMENT ANALYSIS 5.1 Required Demand Management Characteristics At peak load times, the load profile at Salisbury Substation is dominated by residential airconditioning and to a lesser extent commercial and retail sites. Peak loads can be expected during summer heat wave events and are likely to occur on any day during a heatwave due to the predominance of residential air conditioning load. Load shedding would be required in the event of a feeder failure during peak load conditions for up to 12 hours. An initial 4 hour outage would occur for all customers supplied from Smithfield Plains 11kV feeder while implementing the required load transfers. Up to 4.3MVA of load would remain unsupplied after the load transfers were implemented for a period of up to 8 hours while the feeder fault was repaired. The predicted STPIS penalty of the outage is approximately $1.55 Million. 5.2 Demand Management Value The following table indicates the amount of load reduction required in each year and the available $/kva amount required to make Demand Management viable. To allow for oversubscription (in order to guarantee the load reduction required), a range of deferral benefit values are provided. The stated benefits also include an allowance to cover administrative costs. Table 1 $ per kva available for Demand Management Year Load Reduction Required (kva) Typical number of Days at Risk $/kva available per year for DM 2013/14 2,400 31 40 75 2014/15 2,700 37 35 65 2015/16 3,000 44 30 60 Page 8 of 9

Reasonableness Test: Salisbury Substation 11kV Feeders 5.3 Demand Management Options Considered Various Demand Management technologies were considered to determine their viability to assist in reducing the demand in the constrained area. These DM options were evaluated for both technical feasibility as well as cost effectiveness. 5.3.a Standby diesel generators Establish contracts with customers who have existing diesel generators at their premises and utilise these generators at peak load times. This option is unviable given the very low dollars per kva available as an incentive payment and the low possibility of securing sufficient third party generation to delay the requirement. 5.3.b Install power factor correction Salisbury Substation has an existing power factor of 0.98. Due to the expected growth in the area power factor correction will be insufficient to address the increased demand in the area. 5.3.c Retrofit commercial lighting with efficient lighting. Upgrade existing commercial fluorescent lighting to T5 lighting. The analysis is based on the upgrade of a 400W fluorescent bank with a 2x 80W efficient bank providing the equivalent lumen output. The demand saving per bank is 240W. The estimated cost for this option is $2,500/kVA. Significant disruption to the customer whilst the retrofit is carried out can be expected, which may influence the number of willing participants. 5.3.d Peak load control direct load control Direct load control technology may be viable where tripping many small air conditioning units supplied from a single distribution transformer can be performed. Recent experiences have shown the costs of this solution to range from $300 to $800/kVA. These costs are in excess of the available $/kva to make this Demand Management option viable. 5.3.e Peak load control curtailable load This requires establishing a contract with one or more large customers to turn the power supply off to part of their business or to shift their load to off peak times. Given the size of the load required to be shifted or shed and the dollars per kva available this is not a practicable option in this case. 5.3.f Residential compact fluorescent lamp (CFL) program This option was not deemed relevant due to peak load conditions occurring during daylight hours. Load contribution from residential housing lighting during daylight hours is believed to be minimal. 5.3.g Thermal storage systems A trial installation at a suitable site revealed a saving in load of 150kVA with an expected cost ranging between $1,000 and $1,600/kVA. Smaller scale installations have also been trialled, and are still very much in the development stage (i.e. more expensive per kva). 5.3.h Energy Storage Use of energy storage technology such as flow batteries is typically in the order of $6000 per kva and therefore unviable as a solution to resolve these particular network constraints. 6. CONCLUSION Based on the Demand Management options considered it is not likely that sufficient Demand Management solutions could be implemented to achieve the demand reduction required to make project deferral technically and economically viable. The N-1 constraint on the Salisbury Plains, River and Salisbury East 11kV feeders has therefore failed the Reasonableness Test and a Request for Proposal (RFP) will not be issued. Page 9 of 9