New Delhi : The number 1 compressor , 1987 Demag VK 32C with a discharge pressure of 6.7 bars and an inlet of 35 000 cubic metres per hour, and the synchronous motor 2 900KW 6,6KV needed an upgrade on the electrical MV switchgear, as well as the control system.

“The mechanical upgrade essentially consists of new electrically controlled inlet and outlet vane valves for surge control. The electrical upgrade consisted of new 6.6kV switchgear, but Rockwell Automation reused the oil cooled reactor starter.”

Automatic solid state DC excitation was accomplished on the existing synchronous motor with the use of a DC control and power monitoring system from Rockwell Automation. “This system has proven its reliability where the power factor is being held at unity under all load conditions. But the real test was to envisage the control and instrument system and prove not only energy saving, but provide a true model of the much needed surge control of which there was no information on the existing system.”

Rockwell Automation engineers implemented a new Allen-Bradley ControlLogix PAC (programmable automation controller), complete with GEM standard ICS-Triplex for compressor control software into a new motor control centre (MCC), ready for connection to instruments. The ICS Triplex compressor control software, exclusive to Rockwell Automation, allowed engineers to easily calculate and load the most appropriate surge control for the conditions that the compressor number 1 worked at, together with two other compressors. The control of the inlet vane through the surge control constituted a considerable energy saving.

To collect all relevant information indicating aspects such as pressures, temperatures, power factor, power usage, airflow, trips and alarms, the SCADA system (FactoryTalk View) was installed. During the very first month of operation, the energy saving from compressor number 1 is already significant.

The first compressor is already completed in the end of 2010 and Rockwell Automation is currently working on the second compressor.

“Plans are afoot to upgrade other compressors working on the same manifold, thereby the ICS-Triplex software with an Allen-Bradley ControlLogix will allow for proper load sharing or shifting between compressors and Rockwell Automation envisages an even more substantial saving,” concludes Riccardo Fachin, Rockwell Automation’s Systems & Solutions Business Project Manager. For further details see :

www.rockwellautomation.com