The GB Security and Quality of Supply Standards (GB SQSS) sets out a coordinated set of criteria and methodologies that the GB Transmission Licensees shall use in the planning and operation of the GB Transmission System. These will determine the need for services provided to the GB Transmission Licensees. 

The criterion presented in the GB SQSS represents the minimum requirements for the planning and operation of the GB Transmission system.

Additional criteria, for example covering more detailed and other aspects of quality of supply, are contained in the GB Grid Code and the SO-TO Code, which should be read in conjunction with this document.

Information relating to all aspects of the GB SQSS can be accessed on these pages, including documents relating to proposed amendments to the GB SQSS and information on the GB SQSS Review Group.