Editor’s note: This article first appeared in the June 2015 edition of Water Efficiency.
Standalone Generators
One company providing backup generators for water and wastewater utilities is Kohler Power Systems. “We offer a full line of gas and diesel generators as emergency gensets,” says James Kukla, senior channel manager. “If natural gas is available, utilities can use that. If not, they can use diesel.”
“It takes a lot of starting kilovolt amps to start generator motors, about six to seven times more than is required to actually run the motors once they have been started,” says David Schuh, channel manager for Kohler. “We offer oversized alternators to provide starting kVA [1,000 volt-amps] on our gensets to meet the extra demands for starting.”
According to Kukla, since starting kVA is an issue, some engineers at water plants have installed soft-starting devices to reduce the starting kVA, so they can use smaller generators. “However, when you do that, the devices pull a non-linear current, or a current that doesn’t match the AC sine wave, which causes the voltage to distort on the genset,” he says.
The Eugene Water and Electric Board takes advantage of generator technology for backup purposes. “We use diesel-powered portable and site-installed generators,” says Carman. “The permanently-installed generators are at select sites. We also have several trailer-mounted generators that can be deployed in a variety of configurations.”
When considering backup generators, it is also important to consider the technology that is necessary to connect the generators to the equipment being operated. Most permanent generators are connected with automatic transfer switches, such that if the power goes out, the switches automatically activate the generators by switching from the utility to the generator.
ESL Power Systems is one company offering connection equipment. “For pumps at water treatment and wastewater plants, our most popular unit is the TripleSwitch, which is a manual load-bank testing and portable generator docking station unit,” says Richard Traver, technical sales. “It is popular because it is used with a permanent standby generator and an automatic transfer switch. This allows the utility to load-bank test their permanent generators, which may need to be done monthly.” TripleSwitch allows them to quickly connect the load bank and runtheir tests.
TripleSwitch is a three-way transfer switch that uses three interlocked disconnects to isolate standby generator circuits during COPS (Critical Operation Power Systems) load bank testing. This eliminates the need to strip and reconnect connections each and every time, and is handled automatically with cam connections. It can also double as a manual transfer switch to provide a quick and safe method to connect to a portable generator for redundant backup power. “The TripleSwitch is designed such that, depending on the code for the state, county, or city that requires testing of the permanent backup generator to make sure it is working properly, in case of an emergency, there is a reasonable expectation that the generator will work,” says Traver. “Over time, governing bodies have started to make these requirements more stringent. One reason is that, after some of these large storms we have had around the country, it turned out that a lot of these permanent backup generators simply didn’t work. And they find out they had never been tested.”
Connections are also needed at remote sites. That is, while providing power to the main plant is the most important goal, it is also important to make sure that other locations have power. One effective tool for this is ESL Power’s StormSwitch, a manual transfer switch that provides an economical solution for businesses that want to be prepared for emergency power loss. It ensures a simple hookup to a portable power generator during a power outage. “This is used extensively in remote locations where there are pumps that are critical to the operation of the system, but where there are not permanent standby generators in place,” says Traver. These may include lift stations and bypass stations. The utility can install a StormSwitch at each location. Then, it can contract with a generator vendor in the area such that, if the power goes out, the vendor can deliver the generators to the remote locations. “Since the StormSwitch is already in place at the station, the company’s employees can hook the generator up and start it up,” he says. “The water utility doesn’t need to send anyone out there at all. The generator company can handle everything, as long as the StormSwitch is in place.” There is also an option to include remote monitoring on the StormSwitch. “For this, we will provide the contact and wiring through the breakers, and the utility can provide a signaling device, such as Wi-Fi, that will monitor the StormSwitch from a remote location,” he says. Then, if there is an outage, the signal goes to the central utility office, which then sends a request to the generator provider, which then delivers the generator to the station and hooks it up.
