Comparing generator sizing software

Generator sizing software can help engineers optimize emergency system designs for various load types.

12/12/2013


Figure 1: This one-line diagram represents an example facility that requires a genset to support various loads. Courtesy: ccrdMission critical facilities, such as hospitals, data centers, financial institutions, and other data processing facilities, are required to protect against possible failures of normal electric utility power sources and provide a reliable alternate supply of power. Engine-driven generators are the workhorses that fulfill this need for emergency and standby power. With critical operations—and many times, human life—relying on these systems, it is important for the engineer to design an emergency system that is sized correctly for the various types of loads. If a generator system is undersized, it will cause voltage fluctuations and damage to the generator or equipment it serves, or worse, lose the load entirely. If it is oversized, it may develop maintenance problems and other issues such as wet stacking. 

The most common method for sizing a generator system is total connected load. However, there are various other factors, such as altitude, temperature, fuel type, and application, that influence generator sizing. In today’s mission critical facilities, there are also number of different types of loads, such as fire pumps, chillers, and UPS systems connected to an emergency/standby power system, that can impact the generator size. Each of these load types has a different characteristic during start-up and run time, and reacts differently under various electrical anomalies. Some load types, such as fire pumps, have specific voltage drop (less than 15%) or frequency dip requirements that must be met during start-up. These factors must be considered and analyzed when sizing a generator. 

A detailed analysis of the load and sizing parameters to manually size a generator can be a daunting task. However, sophisticated software is available to assist the designer in sizing and selecting the correct engine. Generator sizing software programs in today’s marketplace are intricately developed to allow for a precise selection that is specifically catered to each application. 

To take an in-depth look at their characteristics, this article presents a hypothetical project using four popular sizing software programs. The case study includes predefined load parameters and includes tips and techniques to optimize the generator size. 

Example project

For this example, consider a facility that requires a standby diesel genset to support various loads (see Figure 1). For these loads, assume that the system can tolerate a maximum of 35% voltage dip and 10% frequency dip. The loads that the genset must support are listed in Table 1. 

Courtesy: ccrd partners

Cummins Power Suite 5.0 GenSize

Cummins Power Suite 5.0 GenSize is a software program developed by Cummins Power Generation, Inc. According to developers, the goal of the program was to have a tool that is easy to use, yet very flexible. The program allows users to input specific parameters, such as voltage drop of motor loads, which allows for maximum flexibility. The program also includes default parameters that help ensure the designer does not undersize a generator. In addition, on each page, it includes page-specific help tools that include tips and direct links for contacting the local distributor. The software is available as an online database that allows the developers to provide current performance data, which is updated regularly to ensure the user is not using obsolete data. Cummins Power Suite GenSize includes an online tool that allows collaborative work in which projects can be shared on the online dashboard among designers or application engineers. The data are not visible to any other user unless the project is specifically shared on the collaboration site. The program is not available in a downloadable version, but projects that have been initiated in earlier versions of the downloadable version can be uploaded to the site. 

Courtesy: ccrd partnersThe example project load data was entered into the program based on a number of available presets (see Table 2). The loads were then assigned to the quantity of steps applicable to the project. After the data are entered and the steps are assigned, the software first selects the smallest genset that meets the performance requirements. For the example project, the software recommended a single 1,500 kW/1,875 kVA genset. In addition to this selection, the program provided alternate selections of generators that may meet the needs and highlights parameters that won’t meet the entered requirements. The program highlights the parameters in two different colors: red if it won’t meet the requirements, and yellow if there are some cautionary items the designer should consider. This feature helps the user understand exactly what is driving the size of the engine and provides guidance on some design changes that could be made to reduce the system size. On the results page, the specification sheets are directly linked to the system-selected engine as well as building information modeling (BIM) results. There are several print features available directly from the results page as well.

Caterpillar Electric Power SpecSizer

SpecSizer is a software program developed by Caterpillar, Inc. It is currently available as a downloadable program from the Caterpillar website, and the software resides on each individual computer. According to developers, the system will be available as an online program by the end of 2013. The program allows users to enter specific parameters, such as percentage of intermittent motor starts, which allows the designer to account for real-world operating conditions when working with systems that have a large quantity of motors. Other features expected in the online version include a specific chiller load parameter, which will help system designers model chiller loads more accurately than the currently available ac load feature. 

The load data from the example project was entered into the program based on the available predetermined loads (see Table 1). As the loads are added, the software displays an up-to-date report of the connected load on the load scenario screen. The loads are assigned a step when the load is entered. After the data are entered and the loads are assigned, the program generates a selection based on the smallest generator that will meet the performance requirements.

For the example project, the software indicated that “no standard SINGLE genset is large enough under the specified site conditions. Sizing will continue by paralleling the minimum number of generator sets necessary.” The software recommended four 550 kW/687.5 kVA paralleled units. The initial results were unexpected because Caterpillar offers larger size engines. After further discussion with the software expert, it was discovered that SpecSizer offers three different input parameters for the genset duty. If emergency standby is selected—as opposed to standby or standby/ESP—the program limits the selection to a very narrow rating category that isn’t applicable here. The software expert indicated that this will not even be an option in the next revision of the software. 

After the correct engine duty was selected, the software recommended one 2,000 kW/2,500 kVA genset. Under the technical section of the software, the program generates project sizing reports and provides a transient performance report showing the true characteristics to be expected per step. The software also provides links where the user can download the spec sheets or go directly to the website. BIM models are currently not available directly through links from the software. However, drawings and other application data are provided. 


<< First < Previous 1 2 Next > Last >>

No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2015 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
Your leaks start here: Take a disciplined approach with your hydraulic system; U.S. presence at Hannover Messe a rousing success
Hannover Messe 2016: Taking hold of the future - Partner Country status spotlights U.S. manufacturing; Honoring manufacturing excellence: The 2015 Product of the Year Winners
Inside IIoT: How technology, strategy can improve your operation; Dry media or web scrubber?; Six steps to design a PM program
Getting to the bottom of subsea repairs: Older pipelines need more attention, and operators need a repair strategy; OTC preview; Offshore production difficult - and crucial
Digital oilfields: Integrated HMI/SCADA systems enable smarter data acquisition; Real-world impact of simulation; Electric actuator technology prospers in production fields
Special report: U.S. natural gas; LNG transport technologies evolve to meet market demand; Understanding new methane regulations; Predictive maintenance for gas pipeline compressors
Warehouse winter comfort: The HTHV solution; Cooling with natural gas; Plastics industry booming
Managing automation upgrades, retrofits; Making technical, business sense; Ensuring network cyber security
Designing generator systems; Using online commissioning tools; Selective coordination best practices

Annual Salary Survey

Before the calendar turned, 2016 already had the makings of a pivotal year for manufacturing, and for the world.

There were the big events for the year, including the United States as Partner Country at Hannover Messe in April and the 2016 International Manufacturing Technology Show in Chicago in September. There's also the matter of the U.S. presidential elections in November, which promise to shape policy in manufacturing for years to come.

But the year started with global economic turmoil, as a slowdown in Chinese manufacturing triggered a worldwide stock hiccup that sent values plummeting. The continued plunge in world oil prices has resulted in a slowdown in exploration and, by extension, the manufacture of exploration equipment.

Read more: 2015 Salary Survey

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
This article collection contains several articles on the vital role that compressed air plays in manufacturing plants.
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.
This article collection contains several articles on strategic maintenance and understanding all the parts of your plant.
click me