Dec 2013
Electricity Transmission
Project Samuel - Grid Data and Measurement Systems
Dec 2013
Jun 2015
National Grid Electricity System Operator and National Grid Electricity Transmission
Michael Coldwell
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Network Innovation Allowance
Comms & IT and Control Systems
The GDMS Technologies uses the system frequency as a communication means to achieve instant 100% national coverage of all electrically connected devices of demand side loads and generation using an existing infrastructure. The system enables direct, instantaneous aggregate power consumption/generation measurements to be performed by the System Operator from the control room.

The GDMS system consists of a transmitter network made up of a number of load devices (resistive heating elements) whose power consumption is modulated in a desired pattern (i.e. a “code”). This pattern is then turned into minute (imperceptible at an operations level) changes of the grid frequency (modulation), and this modulation is subsequently decoded by the other part of the GDMS system – the receiver devices. These are installed onto domestic loads (e.g. hot water immersion heaters) and receive the transmitted codes from anywhere in the grid, and act accordingly.

The system will be operated remotely to enable greater visibility of available capacity and provide finer control for National Grid’s control room to utilise demand side resources in system balancing (response and reserve). The system will also be a highly useful grid inertia analysis tool for National Grid and Network Licensees to provide unique visibility of grid inertia right into the distribution networks. As an operating system, by spreading the transmitted codes National Grid can ensure reliable and resilient broadcast communications and through the use of trusted encryption techniques and anonymised load groups, The system represents a highly secure communications and innovative aggregated measurement channel.

The main objectives of this project will be as followed;

  • To develop a cost-effective communication system to accurately calculate and control domestic demand-side loads.
  • To test and demonstrate whether the GDMS system can control and monitor the demand side loads through an existing operational communication infrastructure.

The key deliverables in achieving these objectives include:

  • A risk mitigation study between project parties and external technical experts to identify and resolve practicability concerns relating to the systems operability on the network.
  • The demonstration of the system to successfully transmit digital information to geographically distributed receivers across the whole of the UK
  • The demonstration of the system to measure, analyse and monitor inertia/flex of the UK grid
  • The validation of the communication system through the following fields;
    • The speed and reliability of the system
    • The flexibility and programmability of the loads behaviour of the system
    • How the system will be triggered to receive transmitted codes of different parameters of length, information and speed.
  • Technical service qualification for the system operator to accept the use of GDMS technology based services for balancing and response or grid measurement.

The completion of a trial plan detailing the nature and scope of the instantaneous power measurement tests to be performed to clearly demonstrate the successful use of system frequency.

The success of the project will be based on the following outputs;

  • A primary report demonstrating the identification and mitigation of risks

  • A secondary report cataloging the installation of transmitters/receivers and testing.

  • A concluding report to define the aggregated power measurement the test results, findings and conclusions.