Electricity Asset Management Plan 2019-2029
212
Vector Limited://
PROPOSED INVESTMENT SUMMARY ($MILLION NOMINAL)
DESCRIPTION
FY20
FY21
FY22
FY23
FY24
FY25
FY26
FY27
FY28
FY29 TOTAL
Northern Subtrans Protection Upgrade Auckland Subtrans Protection Upgrade Northern Zone Sub Protection Upgrade Auckland Zone Sub Protection Upgrade Quay Zone Sub 22 kV CB fail installation
0.50
0.40
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
3.30
1.00
0.91
0.35
2.26
0.40
0.75
1.00
1.20
1.40
1.60
1.60
1.60
1.60
11.15
0.50
1.00
1.20
1.50
1.70
2.00
2.00
2.00
2.00
13.90
0.25
0.25
Total CAPEX
1.75
2.21
2.40
2.50
3.00
3.40
3.90
3.90
3.90
3.90
30.86
AUCKLAND AND NORTHERN TRANSFORMER MANAGEMENT SYSTEMS
NEEDS STATEMENT Transformer management systems (TMS) provide monitoring, control and communications functions for our power transformers fleet. The TMS in zone substations provide the essential function to automatically maintain substation busbar voltages within predetermined limits and this allows us to meet statutory requirements for voltage levels at customers’ premises and also protects equipment from overvoltage. Over time TMS have migrated from various discrete electro-mechanical relays performing specialised functions such as voltage regulation and thermal protection to electronic and PLC type controllers. There are three types of legacy TMS in the network: Electromechanical; Static (electronic components) and PLC. All three legacy systems are proving increasingly unreliable, technically unsupported by equipment vendors and obtaining spares is becoming a challenge. The PLC type in particular lacks technical support and there is little knowledge within Vector with regard to the PLC logic software functionality. When a TMS fails, the ability to automatically regulate busbar voltage is lost that then requires the EOC to manually tap transformers to maintain busbar voltages or place transformers in fixed tap. This increases the risk of violating statutory voltage limits or causing damage to equipment, especially if there is a system event causing rapid change in voltage. In recent years, we have embarked on a programme to install modern microprocessor based TMS’s that are fully configurable with an array of software functions and approximately 50% of the TMS fleet now consist of microprocessor based transformer management. The older TMS’s are unsupervised and have no disturbance or event recording facilities and cannot be employed to provide input parameters for dynamic ratings in the longer term future. The capital investment and programme of work to replace technically unsupported electro-mechanical and PLC based TMS systems need to continue in this AMP period to ensure reliable control and monitoring of zone substation power transformers well into the future. A TMS costs in the order of 3-5% of the cost of a new transformer but this cost will add improved reliability and facilitate safe loading at higher loads.
TARGETED OUTCOMES
CUSTOMER EXPERIENCE
SAFETY
RELIABILITY
RESILIENCE
OPERATIONAL EFFICIENCY
CYBER SECURITY AND PRIVACY
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