REASONABLENESS TEST RT 005/10

Transcription

1 REASONABLENESS TEST RT 005/10 Projected Distribution Network constraint: Piccadilly Distribution Substation Issue 1.0 December 2010 COPYRIGHT ETSA UTILITIES ALL RIGHTS RESERVED This document is protected by copyright vested in ETSA Utilities. No part of this document may be reproduced in any form without limitation unless prior written permission is obtained from ETSA Utilities.

2 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 Piccadilly Substation. 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. 2 ETSA Utilities

3 GUIDELINE 12 REASONABLENESS TEST Constraints on the Piccadilly Substation 1 CURRENT SUPPLY ARRANGEMENT Piccadilly substation is part of the Eastern Hills electricity distribution system. The substation is supplied directly from the 33,000 volt (33kV) sub-transmission network and operated at 33kV stepped down to 11,000 Volts (11kV). The substation is part of a 33kV system supplied from ETSA Utilities Uraidla substation. Piccadilly substation has three 11kV feeders that exit the substation. The Crafers 11kV feeder (SG-02) and Mt Lofty 11kV feeder (SG05) supply the local residential and commercial load. The Piccadilly 11kV feeder (SG-01) is normally supplied from Uraidla Substation with an alternative supply option from Piccadilly Substation. The Piccadilly 33/11kV substation contains two 1.5MVA 33/11kV transformers with a total normal cyclic summer rating of 3.9MVA. The measured demand in 2009/2010 was 3.8MVA and the forecast demand in 2012/2013 is 4.4MVA. The substation will be overloaded at peak times in 2012/2013. Project deferral by transferring load to adjacent substations is not considered practical as this will overload either the 11kV feeder ties or adjacent substations. Piccadilly substation supplies residential, and commercial customers in the township of Piccadilly and surrounding areas (approximately 1,400 customers). The overall supply arrangement is shown in Figure 1 on the next page. 3 ETSA Utilities

4 Figure 1: Piccadilly Electricity Supply System 4 ETSA Utilities

5 MVA Reasonableness Test: Piccadilly Distribution Substation 2 FORECAST LOAD AND CAPACITY The load type at Piccadilly substation contains a strong contribution from residential and to a lesser extent commercial/retail sites. During hot weather in the summer months, residential air conditioning contributes a significant proportion of the peak load at Piccadilly substation. The winter peak load is 88% of the summer peak and is not expected to grow faster than the summer peak load. 7.0 Piccadilly Substation - Load versus Capacity Year Normal Load (MVA) Normal Capacity (MVA) 3 LOAD CHARACTERISTICS The derived load study below is based on the Uraidla 33kV line supplying Piccadilly Substation and Stirling East Substation. The load duration curve shows that Piccadilly experiences high loads for only short periods during summer heat wave events. The peak daily load curve, experienced on the 10 th of January 2010, shows that high loads occurred from approximately 3.30pm to 7.30pm, as is typical for air-conditioning load. 5 ETSA Utilities

6 Load Current (I) % of Load Reasonableness Test: Piccadilly Distribution Substation 100% 90% 80% 70% Load Duration Curve - Piccadilly Substation 60% 50% 40% 30% 20% 10% 0% Piccadilly Percentage of Time 120 Daily Load Curve - Piccadilly Substation :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 Daily Load Curve 6 ETSA Utilities

7 4 NETWORK UPGRADE OPTIONS To prevent the forced shedding of load at peak times, the capacity of the Piccadilly system must be increased. Three network augmentation options have been considered to address the constraint: Establish a new Modular 2, 33/11kV substation incorporating a 6.25MVA transformer and two new 11kV feeders to provide additional capacity to Piccadilly Township. Upgrade the existing Piccadilly substation with a Modular 2, 33/11kV substation incorporating a 6.25MVA transformer. Construct a new 11kV feeder and upgrade the existing 11kV feeder exits. Upgrade an existing substation near Piccadilly (Stirling East) and transfer a significant amount of load from Piccadilly. Preferred Network Solution The preferred solution, when the net present value, timing and effectiveness of related upgrade projects is considered, is to upgrade Piccadilly substation with one Modular 2 33/11kV 6.25MVA Substation. The indicative cost for this project is $2,700, DEMAND MANAGEMENT ANALYSIS 5.1 Required Demand Management Characteristics At peak load times, the load profile of Piccadilly substation is dominated by residential air-conditioning and to a lesser extent commercial and retail load. Peak loads can be expected at the substation during summer after several days of ambient temperatures greater than 38 C. Peak loads are more likely to occur on weekdays and weekends due to the predominant residential air conditioning load. Given Piccadilly substation s load forecast in 2012/13 of 4.4MVA, during peak load conditions up to 0.5MVA of load may need to be shed in the event of the forecast load being reached, which would require the shedding of approximately 165 customers. The rating of Piccadilly substation is expected to be exceeded for a total of 149 hours in 2012/13 with peaks expected between 15:30h and 19:30h. As such load shedding is not practicable many more customers would be shed at peak times due to the limited switching options available on the 11kV feeders. Both the number of customers and the number of days on which this will occur will rise as the loads increases. 5.2 Demand Management Value The following table indicates the amount of load reduction required in each year and the available $/kva amount available 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 2012/ $175 - $ / $140 - $ / $120 - $200 7 ETSA Utilities

8 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. (a) Standby diesel generators Establish contracts with customers who have standby diesel generators on their premises and utilise the generators at peak load times. This option is unviable and uneconomic due to the level of load growth at and around Piccadilly and Stirling. (b) Install power factor correction Due to the expected growth in the area, power factor correction is insufficient to address the increased demand in the area. (c) Retrofit commercial lighting with efficient lighting. Upgrade existing commercial fluorescent lighting to T5 lighting. 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 while the retrofit is carried out can be expected, which may influence the number of willing participants. (d) Peak load control direct load control Direct load control technology may be available where tripping many small air conditioning units supplied from a single distribution transformer can be performed. Recent experiences have shown the costs of this option range from $300 to $800/kVA. (e) Peak load control curtailable load Establishing a contract with one or more large customer s enabling ETSA Utilities to request that they turn power supply to part of their business off or shift load to off peak times was investigated. There are very few customers supplied from Piccadilly substation with a load large enough to individually impact the network. (f) Residential compact fluorescent lamp (CFL) program This option was deemed not relevant due to peak load conditions occurring in daylight hours. contribution from residential housing lighting during daylight hours is believed to be minimal. Load (g) Thermal storage systems A recent installation at a suitable site revealed a saving in load of 150kVA. The cost of this type of installation is expected to range from $1,000-$1,600/kVA. Smaller scale installations have also been trialled and are still very much in the development stage (More expensive per kva). (h) Energy Storage Use of energy storage technology such as flow batteries is typically in the order of $6000 per kva. 8 ETSA Utilities

9 6 CONCLUSION Based on the Demand Management options considered, it is not possible that sufficient Demand Management could be implemented to achieve the demand reduction required to make project deferral technically and economically viable. The constraint on Piccadilly substation has failed the Reasonableness Test and a Request for Proposal (RFP) will not be issued. 9 ETSA Utilities