Transend - Appendix 5 Renewal capital expenditure - Australian ...

Palmerston–Arthurs Lake 110 kV transmission line protection
0BInvestment Evaluation Summary
TNM-GS-809-0720
The transmission line protection on the Palmerston–Arthurs Lake 110 kV transmission line comprises two static distance
protection relays, a GEC Alstom type YTS and a Schulmberger type PDS2000B, both installed in 1977. During routine
testing in 2007 the YTS relay was found to be non-operational and required system spare components to repair. After
repairs were completed the settings needed to be adjusted to compensate for characteristic drift which caused the relay to
over-reach by 20 per cent. Routine testing of the PDS2000B relays has identified that they are deviating from their
expected characteristic due to aging components.
Palmerston–Avoca 110 kV transmission line protection
The transmission line protection on the Palmerston–Avoca 110 kV transmission line comprises two distance protection
relays, an electromechanical Compagne Des Compteurs type RXAP and a static Reyrolle type THR. The RXAP
distance relay was installed in 1968. There are six relays of this type currently in service in the transmission network, and
of these, three have failed over the past four years. The EHV Transmission Line Protection Asset Management plan
(TNM-PL-809-0701) specifically targets the RXAP relays for replacement due to their poor reliability, slow clearance
times and the frequent need for maintenance and repair. The Reyrolle type THR relay was installed in 1984. There are
22 relays of this type in service in the transmission network, of which three have failed over the past four years.
Palmerston–Hadspen Nos. 3 and 4 110 kV transmission line protection
The transmission line protection on the Palmerston–Hadspen Nos. 3 and 4 110 kV transmission lines each comprise two
static distance protection relays; a Schulmberger type PDS2000B and a Reyrolle type THR, all installed in 1979. Issues
associated with both of these relay types are discussed above.
5 CUSTOMER CONSULTATION
Transend will liaise directly with relevant stakeholders regarding the intent, scope and implementation of the project as
part of the project initiation process.
6 BENEFITS
The direct benefits that are achieved through completing the work outlined in the scope of this project will:
� contribute to the achievement of the capital expenditure objectives identified in the Rules;
� provide a safe, secure and reliable electricity supply to customers connected to Palmerston Substation 110 kV by
replacing obsolete, unreliable assets that are in poor condition;
� provide life-cycle cost savings due to reduced operations and maintenance requirements;
� reduce the burden on spare parts management by using standard equipment; and
� align with the recommendations made in the respective asset management plans.
7 OPTIONS ANALYSIS
The following options have been considered for the redevelopment of Palmerston Substation 110 kV:
1. maintain existing assets and defer replacement;
2. replace selected assets in-situ;
3. staged replacement of selected assets over three years; and
4. completely redevelop Palmerston Substation 110 kV.
Other options considered at a high-level, but discounted include:
� greenfield development – this option was clearly not a cost-effective alternative as other solutions can be
implemented within the existing perimeter of Palmerston Substation at a substantially lower cost;
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