Busbar Classification - Results GZ09 Nelson Word - Busbar Classification - Results GZ09 Nelson.docx...

Busbar Classification - Results GZ09 Nelson

System Operations

Transpower New Zealand Limited

June 2017

Version Date Change

1 01/06/2017 Draft

2 01/08/2017 Final – no changes from draft

Position Date

Prepared By:

Reviewed By:

IMPORTANT

Disclaimer

The information in this document is provided in good-faith and represents the opinion of Transpower New Zealand Limited, as the System Operator, at the date of publication. Transpower New Zealand Limited does not make any representations, warranties or undertakings either express or implied, about the accuracy or the completeness of the information provided. The act of making the information available does not constitute any representation, warranty or undertaking, either express or implied. This document does not, and is not intended to; create any legal obligation or duty on Transpower New Zealand Limited. To the extent permitted by law, no liability (whether in negligence or other tort, by contract, under statute or in equity) is accepted by Transpower New Zealand Limited by reason of, or in connection with, any statement made in this document or by any actual or purported reliance on it by any party. Transpower New Zealand Limited reserves all rights, in its absolute discretion, to alter any of the information provided in this document.

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Contact Details

Address: Transpower New Zealand Ltd 96 The Terrace PO Box 1021 Wellington New Zealand

Telephone: +64 4 495 7000

Fax: +64 4 498 2671

Email: [email protected]

Website: http://www.transpower.co.nz

SYSTEM OPERATIONS REPORT: BUSBAR CLASSIFICATION RESULTS

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Contents 1 Results of Analysis for Nelson ......................................................................................................... 4

1.1 Atarau 110 kV Bus ................................................................................................................... 4 1.1.1 N-1 (normal conditions) ....................................................................................................... 4

1.2 Blenheim 110 kV Bus .............................................................................................................. 5 1.2.1 N-1 (normal conditions) ....................................................................................................... 5

1.3 Culverden 220 kV, 66 kV and 33 kV Bus ................................................................................ 6 1.3.1 N-1 (normal conditions) ....................................................................................................... 6 1.3.2 N-1-1 (planned outage conditions) ...................................................................................... 6

1.4 Dobson 110 kV and 66 kV Bus ............................................................................................... 7 1.4.1 N-1 (normal conditions) ....................................................................................................... 7

1.5 Inangahua 110 kV Bus ............................................................................................................ 8 1.5.1 N-1 (normal conditions) ....................................................................................................... 8

1.6 Kikiwa 110 kV Bus ................................................................................................................... 9 1.6.1 N-1 (normal conditions) ....................................................................................................... 9

1.7 Murchison 110 kV Bus ........................................................................................................... 10 1.7.1 N-1 (normal conditions) ..................................................................................................... 10

1.8 Stoke 220 kV Bus .................................................................................................................. 11 1.8.1 N-1 (normal conditions) ..................................................................................................... 11 1.8.2 N-1-1 (planned outage conditions) .................................................................................... 11

1.9 Stoke 110 kV Bus .................................................................................................................. 12 1.9.1 N-1 (normal conditions) ..................................................................................................... 12

1.10 Stoke 66 kV Bus .................................................................................................................... 12 1.10.1 N-1 (normal conditions) ................................................................................................. 12

1.11 Additional Buses .................................................................................................................... 13


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1 RESULTS OF ANALYSIS FOR NELSON

It is assumed that N-1 is the contingency of a bus section with all other equipment in the network in

service (normal conditions). N-1-1 is the contingency of a second bus section with the first bus section

on planned outage at the same bus; all other equipment in the network is assumed to be in service.

A busbar is a single bus section; a bus can be made up of one or more bus sections.

1.1 ATARAU 110 KV BUS

Region: Nelson Normal configuration: One busbar

ATU 110 kV bus has one bus section with two circuits: ATU-DOB-1 and ATU-RFN-IGH-1.

A contingency of the busbar would result in the loss of ATU 110 kV bus and load. There are no other

system issues expected.


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1.2 BLENHEIM 110 KV BUS


BLN 110 kV bus has one bus section with three circuits: ARG-BLN, BLN-STK-1 and 2.

A contingency of the busbar would result in the loss of BLN 110 kV bus and load. There are no other



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1.3 CULVERDEN 220 KV, 66 KV AND 33 KV BUS


CUL 220 kV bus sections are each teed into one of ISL-WPR-CUL-KIK-2 and 3 220 kV circuits and

each section feeds directly into a 220/33 kV supply transformer. The 33 kV is the only ‘physical’ bus.

The 33 kV bus is connected via a 66/33 kV transformer CUL-T1 to CUL 66 kV bus which supplies

Kaikoura (divested) load.

Loss of one of the ISL-WPR-CUL-KIK-2 and 3 220 kV circuits is not expected to have any system

issues. Loss of CUL 33 kV bus will result in loss of CUL and KKI load. Loss of CUL 66 kV bus or CUL-

T1 will result in loss of KKI load.

Planned Outage: CUL 220kV busbar Event: Loss of CUL 220kV other busbar

A CUL 220 kV busbar outage can be managed without taking the 220 kV circuit out of service. A

contingency of the other busbar may result in loss of the other 220 kV circuit. This will result in loss of

CUL and KKI load.


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1.4 DOBSON 110 KV AND 66 KV BUS


This is also discussed in GZ12 West Coast as DOB 66 kV is in GZ12.

DOB 66 kV bus has a single bus section with one circuit DOB-GYM 66 kV. The bus section has two

110/66 kV transformers, one goes to ATU-DOB-1 110 kV circuit and the other goes to DOB-RFN-IGH-

2 110 kV circuit. There is no ‘physical’ 110 kV bus. There are also two 66/33 kV supply transformers

which supplies DOB load. ALD generation is embedded in the 33 kV system.

Loss of DOB 66 kV bus will result in loss of the 110 kV connections, the single 66 kV circuit, DOB load

and ALD generation. Depending on the local generation and load at the time, voltage excursions may

be experienced in the West Coast.


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1.5 INANGAHUA 110 KV BUS


IGH 110 kV bus has a single bus section with six circuits: ATU-RFN-IGH-1, IGH-MCH-KIK-1, DOB-

RFN-IGH-2, IGH-KIK-2, IGH-WMG-ROB-WPT-1 and 2.

Loss of IGH 110 kV bus will result in loss of load at ROB and WPT and loss of generation at ROB. If

load is high GYM-KUM-1 may overload with under voltages at RFN 110 kV, ATU 110 kV, DOB 66 kV

and GYM 66 kV. There is the potential for voltage collapse in the West Coast with loss of load at RFN,

ATU, DOB, GYM, KUM, HKK and OTI.

To reduce the circuit overload and improve West Coast voltages, open the 110 kV circuit breakers on

the DOB 110/66 kV interconnectors post contingency. Loads at RFN and ATU will also be lost.


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1.6 KIKIWA 110 KV BUS


KIK 110 kV bus has a single bus section with four circuits and two 220/110 kV interconnectors KIK-T1

and KIK-T2. The circuits are KIK-ARG-BLN, IGH-KIK-2, KIK-STK-3 and IGH-MCH-KIK-1.

Loss of KIK 110 kV bus will result in MCH, ROB, WPT, RFN and ATU being fed from the West Coast

via the DOB-GYM-KUM 66 kV circuit. If load is high GYM-KUM-1 may overload with under voltages

from MCH 110 kV in the Nelson area to HKK 66 kV in the West Coast area. There is the potential for

voltage collapse in the West Coast with loss of load at MCH, IGH, ROB, WPT, RFN, ATU, DOB, GYM,

KUM, HKK and OTI.

To reduce the circuit overload and improve voltages, loads will have to be shed post contingency. If

applicable this would be managed using a feeder priority list.


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1.7 MURCHISON 110 KV BUS


MCH 110 kV bus has a single bus section with two circuits: KIK-MCH and IGH-MCH. However circuit

breakers 42 and 52 on these two circuits have no protection so a fault on the bus would be cleared by

opening MCH 62, KIK 82 and IGH 402. Load at MCH would be lost.

There are no other system issues expected.


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1.8 STOKE 220 KV BUS

Region: Nelson Normal configuration: Two busbars

STK 220 kV bus has two bus sections with two circuits and one 220/110 interconnector STK-T7.

Normal configuration is as follows; top busbar: KIK-STK-2, STK-T7; bottom busbar: KIK-STK-1.

No system issues are expected following the loss of a single bus section (busbar).

Planned Outage: STK 220kV bottom busbar Event: Loss of STK 220kV top busbar

This will result in loss of STK 220 kV bus and load. There are no other system issues expected.


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STK 110 kV bus has a single bus section with three circuits, one 220/110 kV interconnector STK-T7

and one 110/66 kV interconnector STK-T3. The circuits are BLN-STK-1 and 2 and KIK-STK-3. MOT,

UTK, COB and MPI are connected to STK 66 kV and are no longer Transpower’s assets.

Loss of STK 110 kV bus would result in loss of COB generation and loads at MOT, UTK and MPI.




STK 66 kV bus has a single bus section with one 110/66 kV interconnector STK-T3. MOT, UTK, COB

and MPI are connected to STK 66 kV and are no longer Transpower’s assets.

Loss of STK 66 kV bus would result in loss of COB generation and loads at MOT, UTK and MPI.



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1.11 ADDITIONAL BUSES

Below is a list of buses where the incoming circuit feeds directly into a transformer and/or each bus

section is not connected to the other sections (other than through the lower voltage side) or the bus is

no longer a Transpower’s asset.

Loss of a bus section will affect only the load and generation connected to it. There are no other


ARG/BRR generation is teed into BLN-KIK 110 kV circuit.

COB, MOT, MPI and UTK are fed from STK 66 kV and are no longer Transpower’s assets.

RFN 110 kV bus sections are each teed into ATU-RFN-IGH-1 or DOB-RFN-IGH-2 110 kV circuits and

each section feeds directly into a supply transformer.

ROB 110 kV bus sections are each teed into one of IGH-WMG-ROB-WPT-1 and 2 110 kV circuits and


WMG is teed into the IGH-WMG-ROB-WPT-1 and 2 110 kV circuits. There is no load or generation

connected.

WPT 110 kV bus sections are each teed into one of IGH-WMG-ROB-WPT-1 and 2 110 kV circuits and


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