Andy Osiecki outlines how ABB’s unique automated factory acceptance test system is taking quality assurance procedures for NICAP bay solutions to a new level.
For many of our latest high-voltage substation projects - including new-build, modifications, extensions and refurbishment - we are adopting a bay solution for the substation protection and automation systems based on National Grid's standardised NICAP (National scheme for Integrated Control And Protection) philosophy. This approach, based on pre-engineered, pre- tested and pre-approved equipment offers a number of important customer advantages. For example, we can condense the same functionality into a much smaller footprint, reduce the amount of expensive on-site work and achieve major reductions in the delivery time for this element of the project.
However, the high level of factory testing inherent in the NICAP approach does call for an even greater emphasis on quality assurance procedures. In particular, we need to provide a full audit trail that demonstrates that the factory- assembled equipment will function exactly as it has been designed to do.
FAT
The traditional method of conducting a FAT (Factory Acceptance Test) on bay control and protection equipment would be to hook up the IEDs (Intelligent Electronic Devices) and relays to a network of switches, relays and lamps selected to simulate the substation plant. We felt that this approach, which relies heavily on manual switching and recording of results, no longer offers the levels of rigour and repeatability appropriate for NICAP. So we developed our own dedicated, fully automated, computer-controlled test installation, or System Verification Simulator (SVS).
The SVS at our Stone engineering facilities is based on a high-spec PC running a CITECT SCADA software package with USB serial controlled I/O devices linked to ABB’s own engineered modules that simulate the behaviour of substation plant such as circuit breakers, disconnectors and earthing switches. In effect, we are now able to duplicate the whole substation within the laboratory, and can run automated, self-monitoring test sequences to establish that the substation interacts correctly with the NICAP panels. Over a period of time we have built up a library of test routines to cover all potential situations.
REPEATABILITY
The real beauty of this unique facility is its repeatability. It responds just like the real plant, without human intervention to flick test switches and so on. And because the tests are automated, we have been able to uncover some aspects of the equipment’s behaviour, such as timing issues, that could not be picked up by manual testing.
The automated FAT provides us with a complete record of all the tests carried out and, on satisfactory completion; we can issue the NICAP panels with certification for delivery to site. Should there be any future queries about the way the equipment has functioned in practice, we can easily repeat the tests to check the exact circumstances. And, if necessary, the test plan will be updated to cover it for future FATs.
The facility at Stone has already proved invaluable for our WCML (West Coast Main Line) substation projects - recently the laboratory was filled with over 10 square metres of panels! And, as NICAP is set to grow in importance with both National Grid and DNOs (Distribution Network Operators), the automated FAT will become even busier.