On Saturday, March 24, beginning at 6 a.m., the college will test the Central Heating Plant’s capacity to generate electricity in an emergency. The test will involve shutting off power to much of campus for varying amounts of time, so please note that from 6 a.m. to noon, power will be intermittent and may be lost totally to some buildings. (See list of buildings affected.)
Williams College “Black Start” Test for Standby Generation
Over the past three years, Facilities has been upgrading the steam power plant to allow for emergency and standby power generation during the heating season, using our steam turbine generator. All elements are in place and we are ready to test the system, which will require a power shutdown to many parts of campus, and a “Black Start.” Black Start refers to a condition when utility power is not available and a system is started up using only emergency power. The Black Start will determine whether the system can work in a true emergency, and what power generation we can expect. The system has the potential to fully power all campus buildings fed off our central meter using steam-generated electricity.
Because of the complexity of this system, Facilities has hired an Electrical Engineer who is familiar with our plant systems, commissioned a peer review from a third party, and performed an internal review by Facilities staff. We will be conducting staff training to review all of the sequences and responsibilities, and we are preparing detailed emergency protocols.
It should be noted that this test will not only give us information on the standby capability of the Plant but will also give us a chance to exercise the College’s emergency equipment.
Background
In spring of 2003, the new 3 megawatt Steam Turbine Generator (STG) located at the Williams College Central Steam Plant was commissioned along with the driver: a high pressure, high temperature Boiler #3. At that time, a new 480V service was brought into the Plant to drive the auxiliary equipment for this new system. The rest of the plant remained on the original 240V system which was backed up by a 260 kW standby generator. The original Plant (Boiler #1 and #2) could run on emergency power but not Boiler #3 and the STG.
Three years ago, the plant was upgraded to a new 480V system including the emergency generator which has the capacity to energize the entire Plant. This past fall, a variable frequency drive (VFD) was added to the Boiler #3- 100 HP Forced Draft Fan (as an energy conservation project) which will now allow the start up of Boiler #3 and the rolling of the STG on emergency power.
So now, in theory, the College should be able to generate standby power during the heating season and possibly during the cooling season if we are willing to waste steam and the Plant is not shut down for maintenance. The next step is to test the system to learn if this can be done in a safe and reliable manner.
Benefits of the Test
The test will accomplish the following:
- Verify that Standby Power can be generated during a utility outage and delivered to all or a portion of the central campus buildings
- Verify the amount of power that can be delivered
- Confirm the locations that can use the standby power
- Define the operational procedures to generate and distribute power in a safe and reliable manner
- Test individual building systems for performance during power fluctuations
What Could Go Wrong
In the worst case, the automatic load control could fail which would trip the breaker to the steam turbine generator. Additionally, the steam flow may be hard to control at start up (this will be done by a manual venting of the turbine exhaust). Inadequate steam pressure could also trip the generator breaker. In either case, the steam generator would not function and no power would get to campus. We would abort the test and Utility Power would be reestablished to the Campus within a short period of time. Buildings with standby or emergency generators on automatic switches would have emergency power in any case. In no instance would any building on campus be without power for more than 6 hours.
Proposed Timing
The proposed time of the test would be March 24, 2012 starting at 6:00 AM (middle weekend of Spring break).
The duration of the test would be six hours, plus or minus. Emergency power will be distributed to buildings sequentially, until we reach our emergency power capacity. The test will end and normal power will be reestablished no later than 12:00 PM.
Buildings Affected
Only buildings which are serviced by our central electric meter will be affected. The attached list outlines which buildings are on the central meter, and which of those buildings have their own emergency generators. Please note that some buildings have standby generators that are on manual switches. These buildings will not have power until the steam generator kicks in, as we will not be deploying staff to manually switch these generators on. (See list of buildings affected.)
If the test goes as planned, the buildings without any independent emergency power could see an outage period of up to 6 hours. The Science buildings are served by standby power which will maintain the animal room and critical equipment as well as power to the red outlets. Jesup Hall will have standby power to its server room, including HVAC systems.
Steam heat to buildings will be temporarily interrupted, however as soon as the steam plant power is restored, steam to buildings will return. We do not anticipate any noticeable temperature changes as a result of the test.
What will happen during this test?
The sequence that would be followed to test the Standby Generation mode would be as follows:
- 6:00 AM-Open up the main breakers that feed the campus central system- This would kill power to the central part of campus. (See attached building list.) At this time the central buildings would lose normal power and individual emergency systems and some standby generation would start automatically. The buildings on the periphery of campus that have separate electric service from National Grid will not be affected. (Also see attached list)
- The Central Plant would now also be on its own emergency generator and the process to restart Boiler #3 would be taking place and the sequence to restart the STG would be taking place.
- Once the turbine is up to speed and medium voltage breakers are in the correct position the generator breaker would be closed to the distribution system and a priority load would be energized to verify voltage and frequency control. It should be noted that some venting of steam will have to be done at the Plant (roof steam silencer) to add some steam load to the system to maintain adequate flow through the turbine to generate electricity.
- The next action would be to close the breaker to the medium voltage feeder that serves the Central Steam Plant. This would put the plant power back into the normal mode with the emergency generator off and the STG supplying the “normal power.”
- The next action would be to start bringing on feeders to the central campus that could be supported by the steam flow and generation. We plan to energize the science first, as these buildings will increase the steam flow enough to then bring on more electric loads.
- At this time we would verify the capacity of the system under this test mode. The Generator is rated at 3000kW but we need 60,000# of steam flow through the Turbine to reach that level. This would more that satisfy the total campus demand at that time and day of the year. The actual flow that we will see depends on the weather and how much can be vented from the Plant. Too much venting would be wasteful so this will be kept at a minimum.
- 12:00 P.M.-Once this has been completed and the systems have stabilized the test will be complete and the Campus Power and Steam systems will be put back into the normal mode.
