There have been big changes to the world of mains protection recently. As of 27th April 2019, G99 replaced the existing G59-3.4 standard. This means no new connections can be made using G59-3.4.
Sites connected to the network after February 2018 that currently use G59-3.4 will need to upgrade to G99.
Sites connected to the network before February 2018 will not need to comply with G99 – but must be fully compliant to G59-3.4. Updates will likely be required to ensure compliance. This period of upgrades and updates is called The Accelerated Loss of Mains Change Programme and comes directly from the ENA.
The G59-3.4 standard officially came into effect in July 2018. This standard was a modification to the existing G59 recommendation to disallow the future use of Vector Shift protection and to provide new Rate of Change of Frequency (RoCoF) requirements. As part of G59-3.4, the RoCoF relay settings must be set to: 1Hz-1 with a 500ms definite time delay. Vector Shift was disallowed completely.
When this standard was announced, there was no information given on retrospective upgrades and if funding would be made available.
The ENA have now announced the Accelerated Loss of Mains Change Programme, which refers to the retrospective upgrades to G59-3.4.
|Run by?||The National Grid ESO (Electricity System Operator) and the Network Operators (DNOs)|
|Why?||It aims to accelerate compliance with the new Distribution Code requirements (G59-3.4)|
|When?||April 2019 – April 2022 and funding will stop once the cost of accelerating any remaining changes outweighs the benefits achieved by these changes|
|Funded?||Funded by the National Grid through BSUoS (the Balancing Services Use of System)|
|Affected sites?||G59 sites connected before February 2018, sites that have their Loss of Mains protection currently provided by Vector Shift, sites with RoCoF relays where the settings are more sensitive than the settings required by the Distribution Code.|
|Means of Loss of Mains Protection||Synchronous or Doubly Fed Induction Generator Units||Other Units|
|Vector Shift/RoCoF relay (Programmable)||Reprogram to use RoCoF with settings of 1Hz-1 with a 500ms definite time delay. Contact IPU to learn more about reprogramming|
|Vector Shift/RoCoF relay (Not programmable or incapable of setting)||Replace with a MainsPro RoCoF relay with settings of 1Hz-1 with a 500ms definite time delay. Contact IPU directly to get your fully compliant MainsPro relay.||Disable/disconnect Loss of Mains protection|
|Other||No action required|
Remember: existing generation commissioned pre February 2018 does NOT need to comply with G99 BUT must comply with G59-3.4.
Please contact IPU directly if you’re unsure whether you need an upgrade or a complete change of relay. Both of IPU’s mains protection relays, the MainsPro and InteliPro are fully compliant to G59-3.4 and G99.
As part of the Accelerated Loss of Mains Change Programme, there is funding being made available. The window for funding is open between April 2019 – April 2022 (please note the portal for payment applications is available from mid-may 2019).
However, it is strongly advised to complete the upgrade early and submit the payment application as early as is practical. The ENA states that payment will continue until the cost of accelerating any remaining changes outweighs the benefits achieved by the changes.
Sites eligible for payment must:
There will be a fixed payment sum per relay.
There are also two levels of payment:
Contact Ian Wassman at IPU directly to learn more about the payment rates and the costs involved for updating or replacing your relay.
It is strongly advised to submit your payment application as soon as possible as the rates will likely be reassessed in the coming months by the ENA. An early application maximises the opportunity of being accepted.
The National Grid will need to confirm that the correct changes have been made. DNOs will not charge for witness testing.
A list of qualified businesses who are able to undertake the work and provide equipment is available on the ENA website.
According to the ENA: