Sequencing A Faster Start-Up
ComAp adds rapid synchronization to generator controls range
By: Ian Cameron
Engine and generator set controller manufacturer ComAp has announced a new rapid synchronizing feature to add to its range. The Prague, Czech Republic-based company said the benefits of multiset synchronizing installations are recognized by users around the world. It added that optimization of gen-set loading ensures reduced fuel consumption and emissions, while helping to extend the service intervals and, ultimately, engine life.
Built-in redundancy means total failure is less likely and maintenance does not mean 100% loss of generating capability. This can also be coupled with lower capital costs and lead times when compared to larger capacity equipment and lower spares costs during the operating life, ComAp claimed. ComAp’s Radim Girgas, director of the company’s high-end controls division, added, “However, all this comes with one drawback time. Or more importantly, the time required to synchronize all the sets onto the bus together. “This is not normally an issue where time is available such as islanded power station applications, but is essential when the system in question is being used for standby,” he said. “While ComAp provides a fast synchronizing controller thanks to its high-speed phase angle measurement and correction algorithms, there is still a certain amount of time required to achieve all the sets synchronized and ready.
“This blackout time while the sets synchronize is not just inconvenient, it also costs money. In addition, any critical systems running on uninterruptable power supply [UPS] need to be fed during this period, so the UPS needs to be sized accordingly, leading to further costs,”explained Girgas. “Modern rotary UPS systems provide instant backup without the associated battery costs of traditional UPS technology, but only produce useful power for short periods following the failure of the grid supply, limiting their usefulness where multiset installations are preferred. “This small but significant drawback tends to limit standby-type applications for using multiple parallel sets, although we believe we offer a solution with our ‘SUS’ variant application.” ComAp said its new SUS feature changes the start-up sequence of the multiple generators and allows the sets to start online and already synchronized to each other immediately.
According to the company, this means that the system is available at full capacity in the shortest possible time typically eight to 10 seconds from start command to available, which it believes is faster than traditional synchronizing methods, with the time remaining constant even if the number of generators is increased to 10 or 20 or 32.
To allow for slow-starting engines or other problems and avoid delaying availability of the system, any engines that fail to reach running speed within a specified time are “rejected” from the scheme and, if able, are left to perform traditional synchronizing after the majority of sets have become available, said ComAp. Should insufficient sets become available to meet the load’s initial requirements, the system will automatically attempt traditional synchronizing in an attempt to restore power, it added. ComAp said the SUS feature also provides an additional function by allowing one or more sets to start and provide soft magnetizing of feed transformers so that the system does not need to be sized to cope with this peak inrush current.
This can be beneficial in the cost of the installation, but also aids the problem where the grid supply is not capable of supplying the inrush. The islanded generator plants can start and soft magnetize the feed transformer, and allow the grid mains breaker to be synchronized and closed, the company said.