Guidelines on the calculation and use of loss factors
Contents
Overview
Glossary of abbreviations and terms
Introduction
Applicability of these Guidelines
Purpose of these Guidelines
Defined terms
Introductory considerations
13
Overview of calculation methodology
13
Disaggregating the network study area
14
Technical losses
15
Datasets to use in the calculation
16
Determining technical losses
17
Subtransmission (33 kV) network losses (TLA)
18
Zone substation transformer losses (TLB)
19
HV network (22/11/6.6 kV) losses (TLc)
19
Distribution transformer losses (TLD)
20
LV network losses (TLE)
21
Site specific technical losses
23
Determining technical loss factors
31
Determining reconciliation loss factors
32
Determining reconciliation loss factors by time periods
33
Distributor loss factor reporting
35
Appendix A
Requirements of losses information on the registry
36
Appendix B
Loss factor methodologies for embedded networks
37
Appendix C
Loss load factors for distribution transformers
39
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Guidelines on the calculation and use of loss factors
Appendix D
Companion work book #1
40
Appendix E
Companion work book #2
41
Appendix F
Hyland McQueen report
42
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Guidelines on the calculation and use of loss factors
Introduction
7.
These Guidelines are recommended for use by distributors when calculating and
publishing distribution loss factors.
8.
These Guidelines are not mandatory.
9.
These Guidelines have been developed to allow flexibility in application. The degree of
complexity can be chosen depending upon the distributors network size and
configuration, staff resources, software tools and data availability.
10.
Determining technical loss factors is highly recommended as a step in determining
reconciliation loss factors.
11.
These Guidelines are intended to be consistent with the Code and the Model Use of
System Agreement (MUoSA) released for consultation on 11 August 20113.
Compliance with the MUoSA requires calculating loss factors in accordance with these
Guidelines.
12.
The Code can be found on the Authoritys website at:
http://www.ea.govt.nz/act-code-regs/code-regs/the-code/
13.
An example work book (Appendix D) has been produced as a partner document to
these Guidelines. The work book contains:
14.
(a)
equations for including individually calculated customers into the overall
methodology for loss factor calculation
(b)
equations for calculating, summarising and allocating technical loss
(c)
equations for calculating reconciliation loss
(d)
equations for allocating non-technical loss
(e)
a template for reporting relevant results to the Authority.
A second work book (Appendix E) has also been produced that illustrates one possible
methodology for calculating loss factors that apply to periods of less than a year (for
example, summer and winter periods, or day and night periods).
Available from http://www.ea.govt.nz/our-work/consultations/priority-projects/standardisation-muosa-andproposed-code/
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Guidelines on the calculation and use of loss factors
15.
The version of these Guidelines and work books used during consultation can be found
on the Authoritys website at:
http://www.ea.govt.nz/our-work/consultations/retail/loss-factor-methodologies
16.
Where words appear in bold font, this indicates that the words are defined in paragraph
26 of these Guidelines. Terms defined in the glossary of these Guidelines or Part 1 of
the Code are used, but do not appear in bold font.
17.
Throughout these Guidelines, hyperlinked cross-references have been used. Simply
click on the link to be taken to the relevant part of the document.
18.
If you require further assistance, please send an email to
marketoperations@ea.govt.nz
Applicability of these Guidelines
19.
Distributors who own/operate a local network should determine loss factors in
accordance with the main body of these Guidelines.
20.
Distributors who own/operate an embedded network should determine loss factors in
accordance with Appendix B - Loss factor methodologies for embedded networks.
21.
These Guidelines do not apply to any other participants, including:
(a)
distributors who own/operate an islanded network (e.g. Chatham Islands, Stewart
Island, Haast network)
(b)
the grid owner.
Purpose of these Guidelines
22.
23.
Distribution loss factors are important because:
(a)
purchasers of electricity pay for the losses associated with delivery of their
electricity
(b)
the amount paid to sellers of electricity from embedded generators is
scaled up or down by the associated loss factor
(c)
in the case of GXP charging networks, loss factors are used in the
calculation of network charges
(d)
loss factors are used in the retail pricing process by retailers for the sale of
electricity to consumers.
Loss factors directly impact on the cost of electricity faced by all consumers. The
estimated spot market value of losses in distribution networks for 2011 was $118
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Guidelines on the calculation and use of loss factors
million4. Distribution losses are believed to be 5.4% of the energy conveyed on
distributors networks in 20115. Consumers face the cost of all losses, whatever the
cause.
24.
Improved knowledge of technical loss will enable greater understanding of the
location and level of losses within network areas. This will also lead to the identification
of non-technical loss.
25.
The Authority intends to monitor the volume and percentage of non-technical loss.
Inappropriately high non-technical loss would be discussed with the relevant
participants with a view to minimisation, but could ultimately be investigated via an
audit6.
Defined terms
26.
The following terms are used in these Guidelines.
(a)
Individually calculated customer (ICC) means a customer with a point of
connection to a local network or embedded network for whom the relevant
distributor has chosen, or is required to, calculate a site specific reconciliation
loss factor. An ICC may consume electricity, generate electricity or do both.
(b)
Load factor (LF) means the ratio between the average load and the peak load.
It is typically calculated using half hour data. Load factor can be calculated in
accordance with the following equation:
Equation 1
LF
THH
Loadn
( Peak Load ) / THH
n 1
Where:
(c)
Loadn = the 30-minute average load in the nth period
Peak Load = the highest 30-minute average load.
Load loss (also sometimes referred to as copper losses) means the loss
arising from the heating effects of the resistance in the network conductors. Load
loss is proportional to the square of the current and occurs in the
Derived from 1603.2 GWh (distribution losses reported to the Commerce Commission) multiplied by $72.30 per
MWh (average of daily demand weighted spot prices).
Sourced from figure G.4 of the New Zealand Energy Data File (2011 calendar year edition)
Such as provided for under clause 12 of Schedule 15.1 of the Code.
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