Distribution Systems: Making the Connection

The Gas Technology Institute and GE Zenith Controls have developed an advanced paralleling switchgear system targeted at the growing distributed generation market. The system gives generators ‘plug and play’ capability and web-based functionality.

In April 2000, Chicago-based Gas Technology Institute (GTI) and GE Zenith Controls announced a research contract to develop an advanced grid interconnected switchgear system for the rapidly growing distributed generation (DG) market. Less than a year later, in February 2001, the two companies launched the first version of the advanced switchgear technology.

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The two companies’ goal was to create a cost-effective product that would enable a broad range of potential market participants to capture the full economic value that DG offers operating within the electric grid. The result was an advanced paralleling switchgear (PSG) system with a smaller footprint and lower total cost of ownership than other PSG systems available on the market today.

PSG systems are essentially the ‘brains’ of a power generating system. Used on reciprocating engine and gas turbine generators, the PSG controls engine speed to allow synchronization with other generating units via a common bus, or with the grid. The PSG also controls the generator after synchronization has occurred in order to control load.

Figure 2. The first version of the PSG was launched this year
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PSG systems are typically used with generator outputs ranging from 800-2000 kW. The market, currently estimated to be $400 million, is expected to grow significantly as the distributed generation market grows in North America and around the globe.

An attractive market

DG is the integrated or stand-alone use of small, modular electric generation units close to the point of consumption. It is installed for the benefit of a specific customer, the electric system or both. Three independent trends – utility industry restructuring, increasing system capacity needs, and technology advancements – are concurrently laying the groundwork for the possible widespread uptake of DG.

The attractiveness of distributed generation for some utilities and end-consumers has brought it to the forefront of the regulatory agenda in the US. The distributed generation market is expected to grow significantly and so GE Zenith and GTI see a strong market for the new PSG product.

The market for PSG technology in the distributed generation market will depend, however, on the growth and viability of wind energy, microturbines, fuel cells and solar cells, which use built-in static power electronics devices rather than PSG technology which uses mechanical devices for switching.

With strong growth prospects for distributed generation, and with a mandate to promote the use of natural gas, GTI has put significant financial resources into the development of gas engine technology. Part of this work has involved cooperation with major engine manufacturers, such as Caterpillar, Cooper and Waukesha, to find ways of reducing the per-kW cost of gas engines for power generation applications.

Since the per-kW cost of gas engines is higher than that of diesel engines, GTI felt that if the payback period for gas engine technology could be brought down to three to five years, it would be an attractive option for DG. Projects undertaken to help reduce costs included increasing engine ratings through higher engine speeds.

GTI also realised that to achieve their goal of reduced engine costs, other aspects of the power unit, such as the PSG, needed to be modified. GTI therefore teamed up with GE Zenith Controls to look at ways of reducing the capital cost of PSG systems by up to 50 per cent.

At the onset of the project, the objectives and goals were to achieve:

  • Reduced capital costs
  • ‘Plug and play’ simplicity to reduce installation time and labour
  • Integration with leading natural gas engine and turbine generator set manufacturers
  • Conformity with basic electric utility interconnection requirements and ability to incorporate advanced interconnect/generator set protective functions
  • Conformity with existing or projected industry standards
  • Remote monitoring, communications and control functions.

A new generation

Less than one year later, as a result of existing GE Zenith technology and the collaborative effort of the two organizations, GE Zenith Controls has introduced the ‘first generation’ results of their work.

Entellisys Express is a state-of-the-art paralleling switchgear system that can be monitored via the internet. The next generation release of this system, geared specifically for the distributed generation market, is expected to be on the market by late 2001.

Figure 3.The new PSG system incorporates web functionality and remote communications functions
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Entellisys Express interfaces with GE Zenith Controls’ automatic transfer switches and controls the electrical output of multiple engine-generators. Entellisys Express incorporates typical engine-generator control functions, plus power monitoring, power protection, metering and alarm/event logging. And as the world’s only web-configured, web-enabled PSG, Entellisys Express gives users more options than any other system when it comes to accessing and analyzing data.

By working together over ten months, both companies were able to meet the goals they set out at the beginning of the project.

Capital costs reduced: The integrated switchgear and interconnect system (ISIS) costs between $40 to $60 per kWh, a reduction of up to 50 per cent over conventional ISIS systems. Costs were driven down by several factors: a smaller, compact switchgear design, a microprocessor based integrated operator interface-control and monitoring-relay protection system (reduced manufacturing and installation costs), and a streamlined and simplified start-up and commissioning process.

Plug and play simplicity: Installation and start-up is much simpler and straight forward than with other PSG systems on the market. The system has fewer interconnection wires between the engine-generator sets and the switchgear system compared to current systems. Also, the footprint of the system is up to 33 per cent smaller than other systems. The space savings can be significant and make installation easy. The space required for two to five generators could be reduced by 13 to 33 per cent or 4.5 to 25 square feet (0.42-2.32 m2).

Figure 3.The new PSG system incorporates web functionality and remote communications functions
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Components are preconfigured to work in several different scenarios. A system can be up and running in weeks instead of months.

Integration: The heart of the Entellisys Express system is the MX6000 Visual Engine-Generator Controller, a new microprocessor-based controller that is simple, yet highly configurable and versatile. The controller has a colour LCD touch-screen that displays the date and time, operating status of the engine-generator and engine-control switch position (off/reset, cool down, manual or auto). Voltage, frequency, current kVA, kW, power factor and kWh and DC auxiliary voltage are displayed. Active alarms and events are also displayed, together with the date and time that the alarm or event occurred. The controller has easy-to-use Windows software, giving it the look and feel of a desktop computer.

Direct communication with the MX6000 is achieved by using an RS485 port with the engine control module (ECM) on the engines. The port supports both the Caterpillar M5X protocol and the SAE J1587 protocol used by Detroit Diesel engines. For engines not equipped with electronic communication systems, the controller may be hard-wired to the engine through an on-board discrete I/O. The controller is equipped with a second RS485 port for optional I/O boards for analogue input, discrete input, discrete output and LED annunciation boards.

The MX6000 is complemented by the MX3500 Power Protection and Metering System. The MX3500 provides system protection, control and monitoring functions. It features a high-contrast, 80-character backlit LCD display that allows the user to easily monitor any of the measured parameters, inspect setpoint details and relay contact status. The setpoints and configuration are fully programmable via the simple menu-driven user interface and help screens are available to assist users.

Conformity: The Entellisys Express system is UL listed and has a complete integrated protection system to meet appropriate ANSI standards and utility requirements.

Remote communications functions: Entellisys Express gives users many options for monitoring or retrieving data – including access via the internet. Users can access data from anywhere in the world using Internet Explorer or Netscape. Entellisys Express can also be connected to a corporate intranet. In addition, an infrared port allows for wireless communication that makes it possible to download real-time information from the controller to hand-held personal digital assistants.

Major boost

GE Zenith released the first generation of Entellisys Express in February 2001, and expects to release the second generation by the end of the year. While the first generation is not specifically tailored to the distributed generation market, it can be used on DG units in peak shaving applications. The second generation will be manufactured specifically for DG applications.

GE Zenith Controls has a demonstration project operational at its Chicago headquarters, and has already taken an order from a large PC manufacturer. It is also in discussions with a large pharmaceutical company.

“The next generation of this product for the distributed generation market will significantly lower the initial cost of interconnection equipment, and will be simple to install, commission, operate and maintain,” said David S. Leslie, vice president of marketing and project management at GE Zenith Controls. “We expect it will provide a major boost to distributed generation markets.”

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