Appendix N - Detailed Flagging Rules 20160929

APPENDIX N: DETAILED FLAGGING & TAGGINGRULES

Summary of Changes –

Title changed to Appendix N: Flagging & Tagging

System Operator Flagging moved from main section to Appendix N so that all flagging and tagging rules now contained in Appendix N. Rule set out in paragraph 1 has been developed to more clearly reflect the approach being taken by making reference to the use of the most recent Indicative Operations Schedule, which is defined in SDC1 of the Grid Code and Operational Constraints, which is defined in the T&SC making reference to the constraints applied in the determination of the Indicative Operation Schedule for the purposes of system security, priority dispatch and other statutory reasons.

Non-Marginal Flagging has been updated in paragraph 2 to follow the System Operator Flagging definition except by making reference to Unit Constraints, defined in the T&SC making reference to the unit constraints provided by Market Participants in respect of their Generator Unit and applied by the System Operator in the determination of the Indicative Operation Schedule as set out in the Grid Code. This replaces qRTD = HOL or LOL. Non-Marginal Flagging of actions at price breakpoints has also been updated in paragraph 3 to apply non-marginal flags to all Bid Offer Acceptances taken prior to the most recent Bid Offer Acceptances as these prior Bid Offer Acceptances cannot be marginal.

NIV and PAR Tagging now include a paragraph clarifying that calculations to TNIV and TPAR take place in sequence to ensure that no individual paragraph in the calculation could be considered to define the value TNIV or TPAR in isolation.

Minor adjustment of NIV Tagging steps for clarity. No change to the NIV Tagging calculation. Steps that tag actions in opposite direction to NIV are brought up prior to the QRTAG calculation step as this avoids the need to include a recalculation step for QRTAG. This was originally required in a previous draft but is no longer required for the current calculation and this simplifies description.

1 SYSTEM OPERATORNON -MARGINAL FLAGGING

THE MARKET OPERATOR SHALL SET THE NON-MARGINAL FLAG FNMUKΦ EQUAL TO ZERO FOR EACH ACCEPTED BID AND EACH ACCEPTED OFFER FOR WHICH ANY OF THE FOLLOWING SETS OF CRITERIA ARE SATISFIED:

QRTDUΦ = QLOLUΦ;

QRTDUΦ = QHOLUΦ ; OR

QRTDUΦ = QUIΦ 1. For each Imbalance Pricing Period φ, the Market Operator shall use information from the most recent Indicative Operations Schedule to identify whether a Generator Unit’s scheduled output is bound by the presence of an Operational Constraint and where it determines that the Generator Unit is so bound, shall set the System Operator Flag (FSOukφ) for all Accepted Bids and Accepted Offers for that Generator Unit to a value equal to zero.

NON-MARGINAL FLAGGING 2. For each Imbalance Pricing Period φ, the Market Operator shall use information from the most recent Indicative Operations Schedule to identify whether a Generator Unit’s scheduled output is bound by the presence of a Unit Constraint and where it determines that the Generator Unit is so bound, shall set the Non-Marginal Flag (FNMukφ) for all Accepted Bids and Accepted Offers for that Generator Unit to a value equal to zero. 3. For each Imbalance Pricing Period φ, the Market Operator shall identify the Accepted Bids and Accepted Offers corresponding to the most recent Bid Offer Acceptance o for each Generator Unit and shall set the Non-Marginal Flag (FNMukφ) for all other Accepted Bids and Accepted Offers for that Generator Unit to a value equal to zero. 4. where: qRTDuφ is the Real Time Dispatch Quantity for Generator Unit u in Imbalance Pricing Period φ determined in accordance with Appendix [●][Drafting Note to Working Group: this will be defined by the Scheduling and Dispatch rules]; qLOLuφ is the Lower Operating Limit Quantity for Generator Unit u as specified in its Bid or Offer; qHOLuφ is the Higher Operating Limit Quantity for Generator Unit u as specified in its Bid or Offer; and quiφ is [Drafting Note to Working Group : this refers to a price/quantity breakpoint – to be defined as part of the Market Data Submission rules} NET IIMBALANCE VVOLUME TTAGGING 1. For each Imbalance Pricing Period φ, the Market Operator shall set the value of each Net Imbalance Volume Tag (TNIVukφ) by applying paragraphs 5–10 of this Appendix N in sequence and updating the values of each Net Imbalance Volume Tag (TNIVukφ) accordingly.

Setting the iInitial vValue of the Net Imbalance Volume TagNIV Tag 1. For each Imbalance Pricing Period φ, the Market Operator shall set the value of each Net Imbalance Volume Tag (TNIVukφ) to a value an initial value equal to the value of the Imbalance Price Flag (FIPukφ) for each rank k. 2. For each Imbalance Pricing Period φ, where the Net Imbalance Volume Quantity (QNIVukφ) is a positive value, the Market Operator shall set the value of each Net Imbalance Volume Tag (TNIVukφ) to zero for each rank k from 1 to M. 3. For each Imbalance Pricing Period φ, where the Net Imbalance Volume Quantity (QNIVukφ) is a negative value, the Market Operator shall set the value of each Net Imbalance Volume Tag (TNIVukφ) to zero for each rank k from M+1 to N. 4.

Calculation of the Residual Tagged Quantity 1. The Market Operator shall calculate the Residual Tagged Quantity for each Imbalance Pricing Period (QRTAGφ) as follows:

where: is the sum of values over all k;

QABukφ is the Accepted Bid Quantity for Generator Unit u and rank k;

QAOukφ is the Accepted Offer Quantity for Generator Unit u and rank k; and

TNIVukφ is the value of the Net Imbalance Volume Tag for Generator Unit u and rank k, set in accordance with paragraphs 4 – 7 of this Appendix NE2.1.1, E2.3.1(a) and E2.4.1(a) as applicable.

Setting the Net Imbalance Volume Tag in the cCase of a pPositive Net Imbalance Volume Quantity 1. For each Imbalance Pricing Period φ, where the Net Imbalance Volume Quantity (QNIVukφ) is a positive value, the Market Operator shall:

(1.a) Set the value of each Net Imbalance Volume Tag (TNIVukφ) to zero for each rank k from 1 to M and then, using these values, recalculate the Residual

3 Tagged Quantity (QRTAGφ) in accordance with [paragraph The Market Operator shall calculate the Residual Tagged Quantity for each Imbalance Pricing Period (QRTAGφ) as follows: of this Appendix N2.2].

Where the Residual Tagged Quantity (QRTAGφ) is a negative value: determine the value of b and β to satisfy the following equation:

where: b is a positive integer (1 ≤ b ≤ N) and β is a positive real number (0 ≤ β < 1);

TNIVukφ is the Net Imbalance Volume Tag for each Generator Unit u and rank k. set the value of each Net Imbalance Volume Tag (TNIVukφ) to a value of one for each rank k from M+1 to b-1 and to a value of β for rank k = b.

Where the Residual Tagged Quantity (QRTAGφ) is a positive value: determine the value of b and β to satisfy the following equation:

where: b is a positive integer (1 ≤ b ≤ N) and β is a positive real number between (0 ≤ β < 1);

TNIVukφ is the Net Imbalance Volume Tag for each Generator Unit u and rank k. set the value of each Net Imbalance Volume Tag (TNIVukφ) to a value of zero for each rank k from b+1 to N and to a value of 1-β for k = b.

Setting the Net Imbalance Volume Tag in the cCase of a nNegative Net Imbalance Volume Quantity 1. For each Imbalance Pricing Period φ, where the Net Imbalance Volume Quantity (QNIVukφ) is a negative value, the Market Operator shall:

Set the value of each Net Imbalance Volume Tag (TNIVukφ) to zero for each rank k from M+1 to N and then, using these values recalculate the Residual Tagged Quantity (QRTAGφ) in accordance with paragraph The Market Operator shall calculate the Residual Tagged Quantity for each Imbalance Pricing Period (QRTAGφ) as follows: of this Appendix N2.2. Where the Residual Tagged Quantity (QRTAGφ) is a positive value: determine the value of b and β to satisfy the following equation:

where b is a positive integer (1 ≤ b ≤N) and β is a positive real number between (0 ≤ β <1);

QABukφ is the Accepted Bid Quantity for Generator Unit u and rank k; and

TNIVukφ is the Net Imbalance Volume Tag for each Generator Unit u and rank k. set the value of each Net Imbalance Volume Tag (TNIVukφ) to a value of one for each rank k from b+1 to M and to a value of β for k = b.

Where the Residual Tagged Quantity (QRTAGφ) is a negative value: determine the value of b and β to satisfy the following equation:

where: b is a positive integer (1 ≤ b ≤N) and β is a positive real number (0 ≤ β <1);

TNIVukφ is the Net Imbalance Volume Tag for each Generator Unit u and rank k set the value of each Net Imbalance Volume Tag (TNIVukφ) to a value of zero for each rank k from 1 to b-1 and to a value of 1 – β for k = b.

PRICE AVERAGE REFERENCE TTAGGING 1. For each Imbalance Pricing Period φ, the Market Operator shall set the value of each Price Average Reference Tag (TPARukφ) by applying paragraphs 12–14 of this Appendix N in sequence and updating the values of each Price Average Reference Tag (TPARukφ) accordingly.

5 Setting the iInitial vValue of the Price Average Reference Tag 1. For each Imbalance Pricing Period φ, the Market Operator shall set the value of each Price Average Reference Tag (TPARukφ) to an initial value equal to the value of the Net Imbalance Volume Tag (TNIVukφ) for each rank k.

Setting the Price Average Reference Tag if QNIVφ > QPAR 1. For each Imbalance Pricing Period φ where the Net Imbalance Volume Quantity (QNIVφ) is greater than the Price Average Reference Quantity (QPAR): Determine the value of b and β to satisfy the following equation:

Wwhere: b is a positive integer and β is a positive real number between zero and one;

TPARukφ is the Price Average Reference Tag for Generator Unit u and rank k.; and

Set the value of the Price Average Reference Tag (TPARukφ) equal to zero for all k = M+1 to b-1, and to a value of β for k = b.

Setting the Price Average Reference Tag if QNIVφ < -QPAR 1. For each Imbalance Pricing Period φ where the Net Imbalance Volume Quantity (QNIVφ) is less than the negative of the Price Average Reference Quantity (QPAR): Determine the value of b and β to satisfy the following equation:

Wwhere: b is a positive integer and β is a positive real number between zero and one;

TPARukφ is the Price Average Reference Tag for Generator Unit u and rank k.;

Set the value of the Price Average Reference Tag (TPARukφ) equal to zero for all k = b+1 to M, and to a value of β for k = b.