SPHEREA has redeveloped a whole range of protection relays in the context of renovation work on the TROPIC relays equipping the EDF power generation plants.
These relays are classified as K3.
The relays are used to replace obsolete relays without modifying the existing facilities.
|Type of protection||
|Forward / reverse voltage component filter||BCV
|AC voltage minima||BE110Vm
|Zero-sequence voltage maxima||
|Zero-sequence current maxima||TB801
|Current imbalance detection||
|Rotor ground fault||TOGT|
|Circuit breaker trip monitoring||
|Loss of synchronism||TP331T|
|DC voltage maxima||TUG0110|
|DC voltage minima||TUG1010|
|AC voltage maxima||TV1111T|
|AC voltage minima||TVEN3111T|
|Zero-sequence voltage maxima||TVH3111|
AC voltage minima
|Directional true power||TWL1111
Reverse-Engineering and demanding qualification tests
There followed 12 months of reverse engineering on more than 50 types of protection relays, requiring compliance with the customer's extremely stringent reference system, i.e. the RCC-E code on Design and Construction for Electrical Equipment in the nuclear sector. These protection relays form part of the protection and safeguarding systems in the nuclear energy production chain. They are therefore designated as Elements Important for Protection (EIP). They come into play at the start of a possible accident to bring the reactor back to a safe state or a state that can be controlled by the operators. This EIP qualification carries a requirement for rigorous testing including earthquake resistance, extended operation tests over more than 90 days, Electromagnetic Compatibility (EMC) testing, tests for resistance to temperature variations and finally ageing tests.
"The qualification tests, which lasted for more than 24 months, gave our skills a real boost, particularly with regard to dielectric and electromagnetic testing," continues Stéphane Rommel.
On top of these extended operational, electromagnetic, dielectric and environmental tests, which took the SPHEREA teams' knowledge to another level, come a whole host of constraints inherent to reverse-engineering aiming to extend the operational life of systems beyond what was initially planned. These constraints include non-existent documentation, lost skills, management of obsolete components and equipment that is no longer fully compliant with the increasingly strict post-Fukushima regulatory framework.
« Non-existent documentation, lost skills, management of obsolete components and equipment that is no longer fully compliant with the increasingly strict post-Fukushima regulatory framework: these are the constraints inherent to all reverse engineering work in the nuclear domain.»
A dedicated production space
Mass production finally began in 2013, increasing to reach its current level of around 100 relays per year on average. For EDF alone, no less than 140 TROPIC industrial protection relays were manufactured in 2014, 85 in 2015, with the 300th having only just left the factory, and 70 are expected for February 2016.
The launch of high-volume production and the need to qualify the production process led to the commissioning of a dedicated production space in the Andromède building in Toulouse at the end of September 2015. This room was very recently inspected by the customer, in October.
TROPIC relay production room
An opportunity to extend the life of French nuclear power plants
"The investment required for developing and, in particular, for qualifying the relays has been substantial but sales prospects are promising." states Michel Lambert.
This is especially true since prolonging the life of French nuclear plants could require retrofitting around 3,500 items of equipment. The experience acquired in redesigning relays within the post-Fukushima regulatory framework is a substantial asset in tackling these markets."
What is an industrial electrical protection relay?
A industrial electrical protection relay protects the critical elements of an electricity network, particularly from short-circuits, overloads and other malfunctions. They are used in industrial settings such as rail systems, electricity production and distribution systems and very high voltage transmission.