Electricity Asset Management Plan 2019-2029
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Vector Limited://
Strategy Voltage regulators will be installed as and when required to maintain the network supply voltage within statutory limits and to maintain service levels at Vector’s customer service level standards. However ,to resolve network voltage quality of supply issues and/or service level issues preference will be given to the rollout of new technology options, e.g. microgrids, that will provide more than just voltage regulation improvement as a solution for remote areas. Before the rollout of a voltage regulator network, studies will be undertaken to select the optimum solution that will provide the best outcome to customers. 4.7 SECONDARY SYSTEMS Secondary systems are those systems that do not carry load current but are crucial for the safe and reliable operation of the distribution network and its current carrying components. In most instances, secondary systems will exist in zone substations and in some cases in distribution substations. This asset fleet consists of protections systems, SCADA and communications, DC supplies, RTUs and power quality metering. Protection systems are systems that take action during a fault, i.e. detects fault current, trips a circuit to remove the supply after a fault has started to remove the risk of damage to plant, operators and the public. Protection systems are needed to remove as speedily as possible any element of the power system in which a fault has developed. Protection systems include preventive systems such as a gas operated relay that detects gas accumulation produced by an incipient fault in a power transformer or a surge arrestor that prevents a dangerous rise of potential. Population and Age Our fleet of protection relays consist of modern numerical relays, static/electronic relays and electro-mechanical relays. Although electro-mechanical protection relays in Vector’s subtransmission network are reliable, they have no data storage or computing capability to allow engineers to undertake proper and in-depth fault analysis or to analyse the impact on service levels. They are only able to provide trip alarms to the EOC. We have a wide range of electro-mechanical line differential protection schemes that date from the 1960s and in terms of skill sets to maintain these, it is becoming a challenge to employ personnel that are able to maintain and repair these schemes. Our numerical IED protection schemes are based on standardised and modular designs that are laid out in the ESE800 suite of design standards and EDE8000 suite of standard design drawings. Vector has standardised on the IEC 61850 internet based communications system that allows for easy integration of new IEDs into its network. This standard also allows easy communications from SCADA to IEDs and between IEDs. 4.7.1 PROTECTION SYSTEMS Overview
Our population for protection relays is shown in the table below.
No of numeric protection relays
1709
No of static/electronic protection relays
724
No of electro-mechanical protection relays
900
No of auxiliary protection relays
380
Total no of protection relays
3713
Table 4-22 Key statistics for Protection Relays
The graph below shows the age profile for our protection relays but due to legacy data issues there are inaccuracies in our data set especially for the older population of relays and our dataset include some estimates up to 1990.
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