Reserves

The Reserve Management Tool

The inputs to the SPD solver are shown in the figure and table below (adapted from Transpower's Reserve Management Tool (RMT) functional specification). There are two broad categories of input:

1. Energy and reserve offers from market participants
2. Parameters that define the Reserves requirement are calculated mostly by the RMT software application.

Term	Explanation
Generation Offer	Offer made to supply energy by generator
Reserve Offer	Offer made to supply reserve by a Generation Unit
FIR	Fast Instantaneous Reserve
SIR	Sustained Instantaneous Reserve
Interruptible Load Reserve	Reserve available from the reduction of load
Partly Loaded Reserve	Reserve available from increasing generation from unused generation capacity
Tailwater Depressed Reserve	Reserve available by implementing tail water depression in a hydro generator
Load Bids	Bids made by consumers for supply at a GXP
Load Forecast	The estimated load forecast given for each trading period
FIR_RISK_MW	The risk corresponding to the required FIR. Applies to ACCE, DCCE (CE) and ECE.
SIR_RISK_MW	The risk corresponding to the required SIR. Applies to ACCE, DCCE (CE) and ECE.
FIR_MW	The required FIR. Applies to ACCE, DCCE (CE) and ECE
SIR_MW	The required SIR. Applies to ACCE, DCCE (CE) and ECE
CE	Contingent Event
ECE	Extended Contingent Event
RAF	Risk Adjustment Factor. Four different RAFs exist for each island, for CE and ECE for FIR and SIR respectively. To achieve the required reserve, the RAF is multiplied by the risk after deducting the Net Free Reserve.
NFR	Net Free Reserve. The offset from the risk that the RAF is applied to.
ACCE	Contingent Event caused by the loss of (usually) one generator unit.
DCCE	Contingent Event caused by the loss of (usually) one HVDC pole.
Rampupmax	Calculated by RMT. Quantifies the maximum transient overload power that the HVDC link can transfer at the inverter after a Contingent Event, not taking any AC constraints into account.
Halfpole Rampupmax	Calculated by RMT. Quantifies the maximum transient overload power that the HVDC halfpoles can transfer at the inverter after a Contingent Event, not taking any AC constraints into account.
Manual Risk	Manually Entered Min. A fixed risk that cannot be optimised by the SPD solver.
Clearing Price at Nodes	Nodal Price
Cleared Load	Load that will be connected at a cleared price
Rampup	Internally calculated by SPD. Quantifies the steady state power that the HVDC link can transfer after a Contingent Event, taking Benmore bus constraints into account
BEN P1ANMax	The maximum MW north transfer on Benmore Pole 1A
BEN P1BNMax	The maximum MW north transfer on Benmore Pole 1B
BEN P1ASMax	The maximum MW south transfer on Benmore Pole 1A
BEN P1BSMax	The maximum MW south transfer on Benmore Pole 1B
Cleared Reserve	Reserves that will be connected at a cleared price
Cleared Generation	Generation that will be connected at a cleared price
HVDC Bipole Transfer	The MW transfer of the HVDC link
HVDC Branch Limits	Limits in the transfer on each HVDC pole and halfpole. May be reduced due to outages of equipment etc

Relationship between EMarketOffer and RMT

EMarketOffer does not reproduce RMT functionality and must be provided with the RMT generated parameters to be used for final dispatch. The inputs required by EMarketOffer to model reserves appear in the table below.

Input Group	Item	Description
Energy Offers	Price (bands 1-5)	Offer Price in bands 1 to 5 for the Units
	Quantity (bands 1-5)	Offer Quantity in bands 1 to 5 for the Units (always zero for Powerflow Case Data Sources)
Reserves Offers	Price: PLSR/TWD/ILR (bands 1-3)	Price offered by Reserve type for the Unit in bands 1 to 3 for the Unit
	Quantity PLSR/TWD/ILR (bands 1-3)	Quantity offered by Reserve type for the Unit in bands 1 to 3 for the Unit
	Slope: PLSR (bands 1-3)	Unit slope to be used for PLSR offers made by the Unit in bands 1 to 3
Reserves Settings	Reserve Region	North/South Island
	DC Offset FR	HVDC Fast Reserve Risk Offset
	DC Offset SR	HVDC Sustained Reserve Risk Offset
	AC Offset FR	AC Fast Reserve Risk Offset
	AC Offset SR	AC Sustained Reserve Risk Offset
	Base Risk FR	Fast Reserve Base Risk (Manual Risk)
	Base Risk SR	Sustained Reserve Base Risk (Manual Risk)
	RAF FR	Fast Reserve Risk Adjustment Factor
	RAF SR	Sustained Reserve Risk Adjustment Factor

NOTE: Some of the Reserve requirement data, particularly the AC Offsets, are not published in the data generally available to market participants. You will need to either estimate the value of these input data or obtain examples on request from the system operator.

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