CP1382 'Clarification of IDD Rules for Leading Zeroes'

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CP Progression – CP1382

Meeting Name Imbalance Settlement Group

Meeting Date 18 December 2012

Purpose of paper For Decision

This report provides details of the background, solution, impacts and industry views for Summary CP1382 ‘Clarification of IDD Rules for Leading Zeroes’. ELEXON invites the ISG to approve the CP for implementation in the June 2013 Release.

1. Why change?

Background

1.1 The NETA Interface Definition and Design (IDD) Part 1 contains a definition of the decimal data type (n,d) that is misleading in its treatment of leading zeroes. A leading zero is a ‘0’ digit that leads a number string and which does not increase the numerical value of the data. For example, the zeroes in the string 0002568 are all leading zeroes. In usual decimal notation, leading zeroes are not used other than the zero before the decimal point.

1.2 The full set of rules is contained in Section 2.2.3 (page 15) of the IDD as follows:

n must be greater than or equal to d optional leading “-“ for negative numbers no leading zeros, except where n = d, then number starts “0.” no trailing zeros maximum n digits maximum d digits after decimal point maximum (n-d) digits before decimal point, except where n=d, then number starts with “0.” field may have “-“; from 1 to (n-d) digits; and optionally “.” and up to d digits. Thus the maximum field width is n+2 in the case of a negative value, except for the special case of n=d, where the maximum field width is n+3 including the leading zero. e.g.: -123.456 is decimal (6,3) -0.123 is a decimal (3,3) To clarify the valid values between 1 and -1, the value 0.123 can be represented as: 0.123 or .123

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but not: 00.123 or 0.1230 Valid representations of zero are: 0 0.0 .0 0. -0 -0.0 -.0 -0. but not as a decimal point with no digits.

1.3 The third line suggests that leading zeroes are only allowed where n=d; ‘n’ is the maximum number of digits in the decimal and ‘d’ is the maximum number of digits after the decimal point. An example of why this is misleading would be if there were two data items, N123 and N456, with formats decimal (3,3) and decimal (6,3) respectively. The existing wording of the IDD would mean that values of 0.123 and .123 would be acceptable for N123, but for N456 a value of .456 would be acceptable whereas 0.456 would not.

What is the issue?

1.4 This existing IDD definition is inconsistent with the examples given at the end of the definition (see above), which suggest a decimal like 0.456 should be acceptable. More importantly, this is also inconsistent with the way that the BSC Systems operate, as for any value of n and d central systems would always use the form ‘0.456’ rather than ‘.456’.

1.5 A Party identified this anomaly while testing their validation processes. ELEXON has concluded that the definition in the IDD is misleading and needs to be corrected and simplified.

2. Solution

2.1 CP1382 ‘Clarification of IDD Rules for Leading Zeroes’ was raised on 26 October 2012. The CP will amend the IDD’s definition of the decimal (n,d) data type to be consistent and clearer in its treatment of leading zeroes.

2.2 The IDD definition will be changed to state the following:

maximum n digits maximum d digits after decimal point maximum (n-d) digits before decimal point leading “-” required for negative numbers no trailing zeros no leading zeros other than where -1 < value < 1, then number may start with “0.”

To clarify, the value 0.123 can be represented as: 0.123 or .123,

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But not: 00.123 (an invalid leading zero) or 0.1230 (an invalid trailing zero)

Valid representations of zero are: 0 0.0 .0 0. -0 -0.0 -.0 -0.

but not as a decimal point with no digits.

2.3 As well as being easier to understand, this avoids adding the complication of n=d (which in practice has the same impact as any value being between, but not including, -1 and 1).

2.4 You can find the full IDD redlining in Attachment A.

3. Industry views

3.1 We issued CP1381 for participant Impact Assessment via CPC00719 on 26 October 2012. We received seven responses, of which six agreed with the change and one was neutral.

3.2 The breakdown of responses is shown in the following table. You can find the full collated participant responses to CP1382 in Attachment B and on the BSC Website here.

Respondent role Supports CP? Yes No Neutral

Supplier/Party Agent 3 0 0 Party Agent 2 0 1 Supplier/Generator 1 0 0 Total 6 0 1

3.3 Only one respondent provided reasons for their view, stating that they support the change as it will provide additional clarity in the definition.

3.4 One of the respondents commented on an example provided in the CP1382 form, stating that “We assume that the example in the CP is incorrect, i.e. format decimal (3,3) does not gives 0.1234 and .1234 and format decimal (6,3) does not give .5678, but the principle is correct.”

3.5 ELEXON has clarified that the example given in the CP form was a demonstration of how the current definition of the decimal (n,d) data type is misleading in its treatment of leading zeroes.

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Comments on the proposed redlining

3.6 We received one comment on the proposed redlining to the NETA IDD Part 1:

Comments on proposed redlining

Organisation Doc name Comment ELEXON’s recommendation and location

EDF Energy NETA IDD Part Suggest that 'no leading zeros other ELEXON agrees that the text should 1 section 2.2.3 than where value is between -1 and 1, change from: then number may start with "0."' ‘no leading zeros other than where be changed to value is between -1 and 1, then number may start with “0”.’ 'no leading zeros other than where value is between but not including -1 To: and 1, then number may start with ‘No leading zeros other than where -1 "0."', < value <1, then number may start or with “0”.’ 'no leading zeros other than where We have advised the respondent of value is greater than -1 and less than 1, this recommended change in line with then number may start with "0."', their suggestion. or more simply: 'no leading zeros other than where -1 < value < 1, then number may start with "0."'. Otherwise, there is a possibility of, for example, "01.0", depending on human or software interpretation.

4. Intended benefits

4.1 The current IDD definition is not consistent and can be confusing in its treatment of leading zeroes; at worst it gives a misleading impression of how data is delivered by the BSC Systems. This CP proposes a change to the definition so that it is clearer, simpler and more accurately reflects how the systems operate.

4.2 Also, much of the definition is concerned with the special case where n=d. There are no such data items in the current NETA catalogue; therefore there is no need for such complexity in the IDD wording.

5. Impacts and costs

5.1 The following table summarises the ELEXON effort required to implement CP1382 and the impact on market participants:

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Market participant Cost/impact Implementation time needed

ELEXON £240 (1 man day of effort). 2 June 2013 Release is appropriate. (implementation) Generator/Supplier Minor costs and impacts associated with process 30 days’ lead time required. and procedure changes.

5.2 Two respondents to the Industry Impact Assessment advised that they would require 30 days’ lead time in order to implement this change and that their organisation would incur minor process changes. We requested clarification of the changes required and the associated lead times.

5.3 One of the respondents advised us that they were unable to provide any further details as the internally impacted areas did not provide it to them, and we did not receive any further information from the other respondent.

6. Implementation approach

6.1 We recommend an Implementation Date for CP1382 of 27 June 2013 as part of the June 2013 BSC Systems Release. This is the next available Release; no respondents disagreed with this date, which would allow for the 30 days’ lead time requested by respondents.

7. Recommendations

7.1 ELEXON invites the ISG to:

a) AGREE the proposed amendments to the NETA IDD Part 1 (including the wording change resulting from the Industry Impact Assessment as described in Section 3.6); and

b) APPROVE CP1382 for implementation on 27 June 2013, as part of the June 2013 Release.

Appendices: None

Attachments: Attachment A – NETA IDD Part 1 Redlining Attachment B – Collated Consultation Responses

For more information, please contact: Talia Addy, Change Analyst, BSC Operations [email protected] / 020 7380 4043