A major university needed to expand the capacity of its main substation due to continued campus growth and the addition of air conditioning to all campus buildings. The university had acquired the distribution side of the substation from the local utility a few years earlier and had made major changes to the distribution switchgear. The need to expand, the change in ownership, and recent changes to equipment caused a number of challenges for the university.
One challenge was how to increase the capacity of the substation. The university determined it needed to add a third transformer to the existing two transformers already servicing the university. It also needed to provide protection and controls for the new transformer. The second challenge was how to update the existing two transformers’ protection and controls to match the new transformer. The third challenge was how to take the various drawings from previous upgrades, as well as original installations, and integrate them into a “drawing system” that would be used for the installation of the new transformer and controls, any future changes to these systems, and serve as living documents for the operation and maintenance of the substation.
The university purchased and set in place a new 138kV / 13.8kV, 84 MVA, dual secondary transformer with automatic load tap changers. To complete the installation, Varo provided the design for the following:
• Motor operated disconnect and circuit switcher controls on the transformer high side;
• New main breakers for each of the new transformer’s secondary windings;
• New control panels for the new transformer load tap changer, as well as for the two existing transformers, to match;
• New protective relaying panel for all three transformers;
• A new alarm annunciator panel for alarms from all three transformers;
• New 120 VAC control power UPS.
Varo developed a new drawing system for the substation’s transformers and breakers by integrating existing elementary diagrams from previous work with vendor wiring diagrams. Varo then developed new drawings for the new control panels, transformer, motor operated disconnects, circuit switcher, new main secondary breakers, and all of the physical installation drawings. As built marks, supplemented with field walk downs, were incorporated to provide an accurate drawing package for the substation’s new and existing installation.
The final design package consisted of:
• Elementary diagrams for all system components: switchgear breakers, motor operated disconnects, circuit switcher, bus and transformer protective relaying, load tap charger, controls, and annunciation system;
• Detail wiring diagrams to support all of the above;
• Physical drawing: duct banks, raceways, cable and raceway schedule;
• Pilaster specifications;
• Fire detection system descriptions;
• Ventilation interlock specifications.
In addition, Varo provided continuous construction support through shop drawing review, contractor questions and weekly progress meetings and reviews. Varo also provided commissioning support on site as well as at the control panel vendor’s factory.