Section R: Collection and Aggregation of Meter Data from CVA Metering Systems V19.0
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Introduction
In Section R “relevant BM Unit” does not apply to Secondary BM Units. As such, any reference to BM Unit, or relevant BM Unit, should be taken to mean Primary BM Unit.
Section R sets out:
(a) the submission of data registered in the Central Registration Service (CRS) and Meter Technical Details to the Central Data Collection Agent (CDCA);
(b) the requirements for Parties to submit aggregation rules to the CDCA and the validation of those rules;
(c) the submission of Line Loss Factors to the CDCA for CVA Metering Systems connected to Distribution Systems;
(d) the collection and validation by the CDCA of metered data, the aggregation of such data to determine Metered Volumes and the submission of those Metered Volumes to the Settlement Administration Agent (SAA) and/or Supplier Volume Allocation Agent (SVAA).
Section S covers the rules in relation to SVA Metering Systems. Other than in the paragraphs below on Interconnector BM Units, references to BM Units in this section do not include Interconnector BM Units.
General
When referred to in Section R, the Metered Volume for a Volume Allocation Unit in a Settlement Period is the net aggregate volume of Active Energy (determined at the Transmission System Boundary) which flowed in that Settlement Period to or from the Volume Allocation Unit.
The CDCA collects metered data either by remote interrogation of Outstations or by manual on-site interrogation. The CDCA is responsible for the operation and maintenance of Communications Equipment (other than modems or equivalent exchange links) after it has been installed by the Registrant, but this responsibility ceases when the Metering System stops being registered in the Central Meter Registration Service (CMRS). If there is a fault or failure of a communications link or an error or omission in data available from Outstations, the CDCA will collect the metered data by manual on-site interrogation. The CDCA will provide access to Communications Equipment to the Registrant and the Registrant's nominees, when requested.
The objective of the CDCA is to carry out its functions ensuring that all exports and imports at CVA Boundary Points and Systems Connection Points are properly and accurately taken into account and allocated to the responsible Party in Central Volume Allocation (CVA).
Registration and Technical Details
Data registered in the Central Registration Service (CRS) (as outlined in Section K) is submitted to the CDCA by the Central Registration Agent (CRA), and Registrants of Metering Systems submit Meter Technical Details to the CDCA (as outlined in Section L). The CDCA validates the registration data and Meter Technical Details, records and maintains the data and informs the CRA or Registrant (as appropriate) of any data that is invalid or missing so that it can be corrected and resubmitted.
Aggregation Rules
Aggregation Rules describe how import or export active energy metered data is to be aggregated so that, for any Settlement Period, the Metered Volume for a Volume Allocation Unit can be calculated.
Submission of Aggregation Rules
The Lead Party of each relevant BM Unit is required to submit Aggregation Rules for that BM Unit which relate to each of the Metering Systems associated with that BM Unit and provide for the determination of the BM Unit Metered Volume.
National Electricity Transmission System Operator (NETSO) submits a set of Aggregation Rules in relation to each transmission-connected Interconnector which relate to the Metering Systems associated with that Interconnector and provide for the determination of the Interconnector Metered Volume.
Each Distribution System Operator (DSO) submits a set of Aggregation Rules:
(a) in relation to each Grid Supply Point (GSP) at which its Distribution System is connected to the Transmission System, which relate to each Metering System associated with the GSP and provide for the determination of the GSP Metered Volume;
(b) in relation to any GSP Group for which the DSO is responsible which relate to each Metering System associated with each Systems Connection Point on the GSP Group and provide for the determination of the GSP Group Metered Volume;
(c) in relation to each Distribution Interconnector which is connected to its Distribution System, which relate to the Metering Systems associated with that Interconnector and provide for the determination of the Interconnector Metered Volume.
For the purposes of (b), the DSO responsible for preparing a set of Aggregation Rules shall be the Licensed Distribution System Operator as at 1 August 2003 or, if none was responsible or if the Panel consents to them relinquishing responsibility, another DSO can take the role subject to agreement.
For a BM Unit comprising a range CCGT Module, the Lead Party can submit more than one set of Aggregation Rules reflecting different operating configurations of the Plant and inform the CDCA as to which of the sets of Aggregation Rules are to be used in determining the BM Unit Metered Volumes. The procedure for doing this is detailed in BSCP75 and the information submitted must be consistent with that provided by NETSO under the Grid Code.
Aggregation rules must be submitted (or resubmitted) as per the procedures specified in BSCP75:
(a) at the time that any Party applies for registration of a Metering System;
(b) when there is a change in any Metering System or the composition of a Volume Allocation Unit;
(c) at any other time where it is necessary to do so to ensure that the rules submitted continue to meet the requirements specified in Section R for Aggregation Rules; and
(d) at any time if requested to do so by the CDCA.
Requirements for Aggregation Rules
The preparation of Aggregation Rules must be undertaken in good faith and in accordance with Good Industry Practice and so that the volumes determined using those rules are those which should be determined as Metered Volumes.
Aggregation Rules must be algebraic rules that comply with the requirements specified in BSCP75. In particular, they may only specify certain data (metered data, Line Loss Factors and constants, or intermediate terms derived from such data) and certain operations or combination of operations (addition, subtraction, multiplication and division). The Panel can determine a date from which logical 'IF' operations can be permitted in Aggregation Rules. Operations that are performed automatically by the Metering Equipment should not be provided for in the Aggregation Rules.
Where Aggregation Rules relate to a Metering System connected to a Distribution System, the Aggregation Rules must specify (or enable the CDCA to determine) which Line Loss Factors are to be applied, and how, in determining Metered Volumes.
The Aggregation Rules must, amongst other things, be consistent with any supporting information provided (which can be requested by the CDCA), the registration data received from the CRA and the Meter Technical Details submitted to the CDCA. Where the rules for more than one Volume Allocation Unit relate to the same Metering System, each of the Parties responsible for the Aggregation Rules must have consented to them and those two (or more) sets of Aggregation Rules must be consistent with each other and ensure no double counting or omission of metered data. Where the Aggregation Rules relate to a Metering System connected to a Distribution System, they must provide for the relevant Line Loss Factors to be applied to metered data before any metered data to which different Line Loss Factors are to be applied is combined and before any combination of import and export active energy metered data.
The CDCA validates the Aggregation Rules submitted in accordance with the requirements specified in Section R and BSCP75. On the basis of information provided to it, the CDCA will at all times keep under review and determine whether any Party which should have, has failed to submit or resubmit a set of Aggregation Rules.
Where the CDCA determines not to validate a set of Aggregation Rules submitted or decides that a Party has failed to submit a set of Aggregation Rules, the CDCA will notify the relevant Party and request a submission (or resubmission) of the Aggregation Rules. In the absence of validated Aggregation Rules, the CDCA will use a prevailing set of Aggregation Rules in relation to the Volume Allocation Unit if an appropriate set exists (and inform the Panel and affected Parties that this is the case). Where no appropriate prevailing set of Aggregation Rules exist but Metered Volumes have to be determined for the Volume Allocation Unit, the CDCA will determine what it considers to be a reasonable set of Aggregation Rules to be applied until such time as a valid set is submitted (and will notify the Panel and affected Parties of the set determined by the CDCA). The Panel can instruct the CDCA to revise the Aggregation Rules that it has determined. In the determination of Metered Volumes, the CDCA can use validated Aggregation Rules that have been submitted after the Settlement Day to which the Metered Volumes relate but before the Interim Information Volume Allocation Run.
The CDCA is required to keep a record of all prevailing Aggregation Rules and must provide a copy to the Party responsible for submitting them or any related Party upon request.
The CDCA shall constantly keep under review whether all sets of Aggregation Rules taken collectively result in the proper determination and allocation of Metered Volumes for Volume Allocation Units and whether there is any Metering System installed whose data is not being taken into account fully in Aggregation Rules. If it finds any defects or omissions, the CDCA must report this to the Panel and discuss with the Panel how the defect or omission can be remedied.
Line Loss Factors
Section K sets out the rules for establishing Line Loss Factors for relevant CVA Metering Systems connected to Distribution Systems. Elexon is responsible for submitting (in accordance with BSCP128) the approved Line Loss Factors (or default Line Loss Factors as the case may be) to the CDCA. The CDCA assumes a default Line Loss Factor of 1.0 (or any other default provided in BSCP128) if Line Loss Factors have been specified in the Aggregation Rules but have not been submitted to it, until such time as the Line Loss Factor is submitted.
Collection, Validation, Estimation and Aggregation of Metered Data
The CDCA collects metered data in respect of each Settlement Period from all Outstations associated with CVA Metering Systems. If the metered data collected is in power values, the CDCA converts it into energy values (and any Aggregation Rules submitted in relation to such metered data should not provide for this conversion from power to energy).
The CDCA establishes principles for validating metered data (which are approved by the Panel) and validates the metered data that it collects. If any metered data is invalid or missing, the CDCA notifies the relevant Meter Operator Agent (MOA) and Registrant, as per the procedures outlined in BSCP03.
If metered data is invalid or missing or, in the case of active energy metered data, errors in the data are notified to the CDCA by the relevant MOA, or the CDCA thinks the data is erroneous or the Metering System is found to be outside accuracy limits, the CDCA is required to notify the MOA and Registrant and, in the case of active energy metered data, the CDCA is required to estimate the data for the relevant Settlement Periods. The CDCA notifies its estimate to the Registrant and to the MOA and will discuss it with the Registrant if the Registrant so wishes. Following a discussion with the Registrant, the CDCA can decide to revise the estimate. The estimate is used in determining the Metered Volume for the relevant Volume Allocation Unit(s). BSCP03 sets out the procedures for estimating metered data. A Party has the ability to raise a Trading Dispute in relation to estimates of metered data in accordance with the rules specified in Section W.
The CDCA is required to send a report on any estimated metered data it used to Elexon (if requested), the relevant Registrant and MOA, any related Party, the DSO (if any) to whose Distribution System the Metering System is connected and NETSO if the Metering System is directly connected to the Transmission System.
For each Settlement Period the BM Unit Metered Volume for each relevant BM Unit, the Interconnector Metered Volume for each Interconnector, the Metered Volume for each GSP and the GSP Group Metered Volume for each GSP Group are determined by the CDCA by aggregating the metered data collected (including, where relevant, scaling the metered data by the applicable Line Loss Factors) in accordance with the applicable Aggregation Rules.
The CDCA establishes Aggregation Rules for determining each GSP Group Take and determines the GSP Group Take. The CDCA keeps these rules under review and updates them as necessary upon any change in relevant details or if an error is identified in the rules. A copy of these rules is provided to the Panel, Elexon and each DSO whose Distribution System is comprised in a GSP Group, and upon request to any other Party. If the CDCA identifies an error in the rules it must notify details and discuss with Elexon or (if the Panel requires) the Panel or the BSC Auditor whether exceptional circumstances justify an adjustment in Settlement relating to Settlement Days before the error was corrected.
For each Settlement Period in any Settlement Day, the CDCA (as per the steps in BSCP01) calculates and submits Metered Volumes for each Volume Allocation Unit and GSP Group Take for each GSP Group, when the Credit Cover Volume Allocation Run, Interim Information Volume Allocation Run, the Initial Volume Allocation Run and the Timetabled Reconciliation Volume Allocation Runs are required (in accordance with the Settlement Calendar) and whenever a Post Final Volume Allocation Run is requested by the Panel.
For Volume Allocation Runs after the Initial Volume Allocation run the CDCA can use adjusted or revised data (registration data, Meter Technical Details, Aggregation Rules, Line Loss Factors and metered data) where the data has been revised following a Trading Dispute or where the BSC otherwise allows for the CDCA to use adjusted or revised data.
The CDCA submits the GSP Group Take for each GSP Group to the SVAA and the Settlement Administration Agent (SAA), the Interconnector Metered Volumes to the relevant Interconnector Administrator (IA) and the SAA, BM Unit Metered Volumes to the SAA and Metered Volumes for Credit Qualifying BM Units to ECVAA.
Further Functions of CDCA
The CDCA undertakes proving tests on CVA Metering Systems and reports any errors to the relevant MOA and Registrant.
Interconnector BM Unit Metered Volumes
Section T contains the rules for determining BM Unit Metered Volumes for Interconnector BM Units of the Interconnector Error Administrator (IEA).
The BM Unit Metered Volume for each other Interconnector BM Unit is the total Active Energy determined by the IA. The IA derives these energy volumes from the final Expected Transfer for each Interconnector BM Unit, which is also determined by the IA. The final Expected Transfer is determined based upon the final Interconnector Scheduled Transfer that is sent to the IA by the Interconnected System Operator. The final Interconnector Scheduled Transfer represents the original transfer scheduled across the Interconnector, which is based upon the Active Energy flow scheduled for all Interconnector Users (which in turn is based upon Physical Notifications submitted) adjusted, broadly speaking, for any derating of the Interconnector capability after Gate Closure and any acceptance of a Bid or Offer from an Interconnector User by NETSO. The total transfer scheduled across the Interconnector prior to or at gate closure cannot exceed the capability of the Interconnector.
The IA submits to the SAA BM Unit Metered Volumes for Interconnector BM Units for each Settlement Period for each Settlement Day.
NETSO is allocated two notional BM Units for each Interconnector (one Production and one Consumption) which are used for the purpose of allocating and accounting for energy comprised in any system-to-system flows. System-to-system flows are those that arise for the purpose of securing stability of operation on the Total System or an External System. NETSO determines (on a basis approved by the Authority) amounts of energy resulting from system-to-system flows and notifies the IA of the net amount of any flows that arise. The IA then calculates the BM Unit Metered Volumes for NETSO's Interconnector BM Units based on the values notified, and submits them to the SAA.
Demand Disconnection Events
Under the Grid Code NETSO can issue instructions (Demand Control Instructions) to DSOs in order to reduce demand in their areas (e.g. if NETSO is unable to call upon sufficient generation to meet the current demand). DSOs can reduce demand either through initiating voltage reduction and/or disconnecting consumers through Demand Disconnection.
In the event that a BM Unit that is embedded within a Distribution System is disconnected from the Distribution System due to a Demand Disconnection Event, the impacted DSO needs to send the BM Unit ID and the start/end date and time (in Co-ordinated Universal Time) for each disconnected BM Unit to the CDCA. The DSO needs to do this within five business days of the Demand Disconnection Event ending.
For each Demand Control Impacted Settlement Period the CDCA must estimate the Period BM Unit Demand Disconnection Volumes (QDDij) for such embedded BM Units in accordance with BSCP03. The CDCA estimates these volumes so that Parties are not unduly disadvantaged in Settlement as a result of a Demand Disconnection Event. If NETSO notifies the CDCA of a Demand Control Event in relation to a BM Unit that is directly connected to the Transmission System, the CDCA also needs to estimate the Period BM Unit Demand Disconnection Volumes for these BM Units in the same way. The CDCA must then submit these volumes to the SAA.
Need more information?
For more information please contact the BSC Service Desk at bscservicedesk@cgi.com or call 0370 0106 950.
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