05/05/03 - by Ved Prakash Sinha
The PQFA range of Active Filters has many applications, mostly in Industrial loads. However, sometimes, these filters are used to clean the harmonic generated in a commercial / residential building. One such recent application consists of three sets of three module Active Filters each, in the Canary Wharf project in the old London dockyards area.
This district is being re-developed. One of the buildings being constructed there is called Haron Quay 2 (HQ2), promoted by Lehman Brothers, an Investment Banking Corporation. The loads in this building are being fed by one UPS system manufactured by Liebert.
Three UPS systems are being installed for the tenants’ loads. They are known as the Red, Yellow & Blue UPS systems, each dedicated to one switch room (Red, Yellow or Blue).To every UPS system a three module active filter (PQFA - B + C) will be connected. As a special requirement, these filters were supplied in special RAL colour shades to match the name of the switch room.
Each UPS system comprises four No. 12-pulse 800kVA UPS modules in parallel with facility to add an extra 800kVA UPS later.
The PQFA’s are connected on the “load” side of the UPS and are to compensate for harmonics produced by the tenants' loads. Each UPS has a 5000 Amp By-pass / Static switch. Therefore the PQFA’s are also dimensioned for harmonic reduction when the total installed load is fed directly from the mains.
These PQFAs were successfully factory tested in presence of experts from Liebert as well as the end customer.