Photocells paper for UMSUG
1.1.
Background
There has been some confusion in the past regarding the different types of photocells, in particular
latching relay cells. Power Data Associates became involved in this issue recently when querying some
codes used by a customer. Following on from these discussions with some of the photocell
manufacturers, we believe the codes for photocells could be simplified as well as some further details
added to the other existing photocell descriptions in the OID.
1.2.
The Issue
Currently there are the following control devices listed in the OID:
Time Switch Controllers
Thermal Photocells
Hybrid Photocells
Electronic Photocells
Electronic Photocells (Latching relay)
Infra Red Photocells
Electronic Photo Cell Timeswitch
Electronic Controls (e.g. CMS devices)
Following discussions with the manufacturers, photocells in the 94…, 95… and 97… range could all be
part of the ‘94’ regime.
This is because there is no real difference that is easily discernable between the different types of
photocells and customers do not readily distinguish between them in their inventory. To use one
example, the SELC latching relay cell also has a solid state in it. The latching relay may only use energy
the moment of switch on/off, however it will continue to use power continuously to monitor the light levels.
The manufacturers have all (SELC and Zodion) stated that the cells being produced today are quarter
watt regardless.
It would also be useful if the OID was updated to include some additional description to define how IR
cells and electronic cells consume power during the day:
Equipment
Codes
91
92
Description
Comment
Time Switch Controllers
Thermal Photocells
93
Hybrid Photocells
94
Electronic Photocells
95
Electronic Photocells
(Latching relay) Not in use
Infra Red Photocells
Electronic Photo Cell
Timeswitch Not in use
Electronic Controls (e.g.
CMS devices)
Load is continuous
Are based on 3 watts when the lamp is switched "OFF" and 0 watts
when lamp is switched "ON".
Are based on 3 watts when the lamp is switched "OFF" and 0 watts
when lamp is switched "ON".
Can only to be used for specifically approved cells. Load is
continuous, covers solid state, latching relay and part night
photocells
A photo cell which is fitted with a latching relay which only
consumes power for the instance of switch "ON" or switch "OFF".
Load is continuous
a photo cell controller with an electronic fixed time switch off (Part
night operation).
Load is continuous. Relates to a controller for CMS equipment. e.g.
a node or telecell connected to the lamp/ ballast to facilitate
dimming and switching
96
97
98
Power Data Associates Ltd
www.PowerDataAssociates.com
Photocells 20110701
+44 (0)1525 862 870
Wrest Park, Silsoe, Bedfordshire MK45 4HR
VAT GB 813 7743 24 Registered in England No. 4711888
1.3.
Recommendations
UMSUG is invited to recommend to SVG:
1
Revise the OID to provide additional clarification over how IR and electronic photocells consume
power during the day; and
2
That all electronic photocells are coded as ’94…’
Photocells 20110701
Page 2 of 2
Switch Regime Spreadsheet paper for UMSUG
1.1.
Background
There have been a lot of changes made to the ELEXON Switch Regime spreadsheet as a result of both
the recent ELEXON burn hour review and the changes required for passive Half Hourly trading.
As a result, the switch regime spreadsheet is now quite confusing with multiple greyed out entries for the
same regime code. This makes it difficult for customers (and industry participants!) to use. In addition,
there are a number of pieces of information that have been omitted from the spreadsheet when updates
have been made over the years as well as there being some erroneous entries.
1.2.
Proposal
In order to address the issue of the greyed out lines, there are two proposed solutions. As a ‘once off’
activity the greyed out lines could be deleted from the current spreadsheet and an old version of the
spreadsheet stored on the ELEXON website for any participant that wanted to refer to the old hours.
Alternatively two spreadsheets could be maintained, the first being the ‘current’ view and the second a
more detailed one for industry use, which would contain everything (including the greyed out lines).
Customers and industry participants will not need this information for day to day operations.
1.3.
Current Issues
There are a number of issues highlighted in the spreadsheet attached to this paper. Red denotes missing
information, blue denotes items that should be deleted and yellow is an issue/query.
1.4.
Recommendations
UMSUG is invited to:
1
Discuss the issues highlighted in the switch regime spreadsheet and propose solutions to
ELEXON / SVG as appropriate; and
2
Agree that a second spreadsheet should be created with the greyed out lines removed.
Power Data Associates Ltd
www.PowerDataAssociates.com
Switch Regime Spreadsheet 20110701
+44 (0)1525 862 870
Wrest Park, Silsoe, Bedfordshire MK45 4HR
VAT GB 813 7743 24 Registered in England No. 4711888