OC7

OC7 sets out the requirements for the exchange of information that has had or will have an operational effect on:

• The GB transmission system
• The system of a user or users.

It also sets out the types of GB transmission warnings which may be issued by NG

• If an operation happens on the GB transmission system which may have an effect on the operations of a user's sytem, NG will notify the user - usualy via fax.
• If an operation happens on a user's system which may have an effect on the transmission system or any other user's system, then the user will notify NG.

Any notifications should be given as far in advance as possible.

NG will pass on the information we require, but will not reveal the identity of the party to cause the initial operation/event.

• A network operator may pass on information from NG to a generator
• A generator may pass on information from NG to another generator with a generating unit on the same or connected system
• A generator or network operator may NOT pass information on other than stated above.
• A generator with a an affiliated supplier may pass on the same limited information and the supplier may pass this on to its customers.

Transmission system warnings provide information relating to system conditions or events and are intended to alert users of possible/actual plant shortage during certain periods and the possible consequences. Will be issued by fax.

Types of system warnings:

• Inadequate system margin - will state the periods, MW shortfall and the intended consequences
• High risk of demand reduction - warning will specify the network operator and non embedded customers who may recieve demand reduction instructions as well as the specific periods when instructions will apply
• Demand control imminent - will be issued when demand reduction is anticipated within the next 30 minutes and will specifiy network operators who will recieve the instruction. NG will either cancel the warning or re-issue the warning no later than two hours from first issue.
• Risk of system disturbance - issues when there is a widespread and serious disruption to the whole or part of the system
• Cancellating of system warning.