Drives&Controls & BACK TO BASICS n SPONSORED BY G99: what you need to know When connecting generating equipment, such as regenerative drives, in parallel with a public distribution network, the installation must comply with the G99 engineering recommendation to maintain the integrity of the distribution network in terms of safety and supply quality. Liam Blackshaw, ABB’s product manager for LV drives, examines what G99 means in practice. The G99 engineering recommendation replaces the earlier G59 and details the requirements for generation equipment connected to distribution networks. It has evolved to protect the grid from sudden increases in electricity being exported back onto it. DNOs (distribution network operators) need to ensure that they can distribute electricity safely and maintain a high quality, while accepting the increasing power being generated by generators, regenerative drives, generator modules and renewable sources over 16A per phase. Furthermore, as the grid becomes increasingly decentralised, keeping operations stable and secure while managing constant fluctuations from intermittent power sources, becomes an increasingly delicate balancing act. The G59 standard was established in the 1990s to ensure that all new energy generating installations would be safe and would not compromise wider grid operations. By essentially vetting what comes onto the grid, DNOs are thus able to manage their networks more effectively. G99 superseded G59 in 2019. The new recommendation applies to all new equipment connecting to the grid since then. It brought with it changes to the application process, as well as new commissioning requirements, and new definitions for how generators are classified. The requirements of G99 are generally more onerous than G59, particularly for larger generation schemes, with new requirements for frequency response, voltage control, fault ride-through, fast fault current injection, and variable reactive power. As we move away from large centralised power stations to smaller scale decentralised generation, this allows any new generation coming online to play its part in keeping the grid safe and secure. Regenerative drives are covered by G99, and any regen drive over 16A per phase must comply. ABB’s ACS880 regenerative drive, for example, is certified as being G99-compliant when used with an appropriate and correctly configured interface protection device. It's down to the end-user and the DNO to ensure that compliance is achieved. A formal application is submitted outlining the nature of the project, and testing must be undertaken by the installer to ensure that the installation meets all of G99’s requirements. In some cases, the DNO may wish to observe the testing. The National Grid offers helpful resources explaining the application process and what you need to do, while ABB can advise on G99 matters relating to its drive packages. If you have any queries about G99 and ABB drive packages, please contact Liam Blackshaw at liam.blackshaw@gb.abb.com. applicat for ov reliable Super r f rmo tions ving cables online stock, p huge UK pricing K tions,
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