Woodward Easygen vs PLC control system 1

[meehd88]

I am a facility owner currently working on replacing our genset and paralleling switchgear with 6 x 2.5MW CAT 3516c and am being presented with some options on the controls side.

Option 1 - Woodward Easy Gen + SEL 700G for UV/OV protection, sync check
Option 2 - CAT OEM EGP paralleling controls
Option 3 - Russelectric with Allen Bradly PLC + SEL 700G

I am looking for feedback on the options above in terms of reliability and would like to see if there are better options out there today. Main concern is reliability and serviceability. Cost is less of a issue.

 

[TE163]

I can't speak to the other units but I've been very happy with the SEL products.

 

[FreddyNurk]

My personal preference on any of this is go dedicated hardware rather than a PLC. For the examples you've provided this would mean the EasyGen option.
The previous Woodward model was the default standard for quite a few remote power stations I'd been involved in. I've not used them but the EasyGen also comes in a full redundant controller option if required.
SEL makes good equipment too, and has excellent support.

 

[TugboatEng]

The Caterpillar advantage is their local dealer network. Same day service is often available.

The Caterpillar disadvantage is that you may need to take advantage of that service. The OEM packages have to be more inclusive of a broader range of requirements so they tend to be more complicated as a result.

 

[dpc]

If the PLC is to be involved in generator synchronizing, I'd be concerned - they are generally too slow. Woodward + SEL would be my preferred solution.

 

[wcaseyharman]

In 2023 we had a contractor install an Easy Gen and we installed a 700G and a Basler DECS 400 on a 2.5 MW MP45 that powers a microgrid.

We are pretty happy with it.

We have a site with old Caterpillar controls, it seems very confusing to troubleshoot.

Granted, we were heavily involved in the easygen installation so we are much more familiar with it, but it’s worked very well for us.

I will say the easygen custom logic can be quite convoluted and the modbus tag list can be confusing, but it’s a capable box and is pretty flexible.

We have had good luck with PLC based hydrogovernor controls systems, but we’ve never used a PLC based control system for a diesel. The downsides of PLC based systems seem to be they often have limited electric based I/O, so you need voltage, current and power transducers separate from the PLC rack. Synchronizing is typically done by a separate box (now commonly in the relaying or excitation).

Based on what I know, I’d probably go with the Woodward since it’s pretty common and you’ll be able to get support from multiple companies.

 

[catserveng]

Before you can get a really good recommendation a lot more info would be needed about your system.

Based on your provided info I'd assume this is a standby system with some level of redundancy. But does it only operate as a standby system, or do you expect it to do more?

Is it required to parallel to the utility, either for closed transition return to utility, or some form of demand response?

Will it currently or in the future be required to parallel with other power sources, such a solar arrays, battery systems, fuel cells, etc?

I'd assume that the gens are fitted with medium voltage tailends, but that is not always the case, what is the generators rated voltage? Medium voltage systems tend to require more extensive electrical protections that the EasyGen may not accommodate.

Does the system replace power to a distribution bus (or multiple busses)? Or does it supply multiple ATS switches throughout your facility.

Most systems I work on in this size range use a combination of a Master control based on a PLC, each generator section fitted with a Woodward synchronizer/load control module and a multifunction protective relay, and other controls and protections as required by the overall system design.

A large majority of the systems I was involved in were based on the older Woodward DSLC/MSLC or DSLC2/MSLC2 sync and load share controls. I have done a lot of projects with the EasyGen platform as well, my own preference with the is the backpan mounted 3500XT module, I have run into some reliability issues with the 3400XT type (front panel mount), many of the issues depending on the environment the controls are mounted in.

The EasyGen is a very capable platform, but in asking it to do everything requires an extensive amount of programming and serious shakeout during commissioning, a large number of service calls I did over the years were mainly due to configuration issues. My experience is that with fairly simple systems an EasyGen can "do it all", more complex systems require possibility of needing additional levels of protection, sequencing, remote monitoring and data collection.

Hope that helps, MikeL.

 

[meehd88]

Before you can get a really good recommendation a lot more info would be needed about your system.

Based on your provided info I'd assume this is a standby system with some level of redundancy. But does it only operate as a standby system, or do you expect it to do more?

Is it required to parallel to the utility, either for closed transition return to utility, or some form of demand response?

Will it currently or in the future be required to parallel with other power sources, such a solar arrays, battery systems, fuel cells, etc?

I'd assume that the gens are fitted with medium voltage tailends, but that is not always the case, what is the generators rated voltage? Medium voltage systems tend to require more extensive electrical protections that the EasyGen may not accommodate.

Does the system replace power to a distribution bus (or multiple busses)? Or does it supply multiple ATS switches throughout your facility.

Most systems I work on in this size range use a combination of a Master control based on a PLC, each generator section fitted with a Woodward synchronizer/load control module and a multifunction protective relay, and other controls and protections as required by the overall system design.

A large majority of the systems I was involved in were based on the older Woodward DSLC/MSLC or DSLC2/MSLC2 sync and load share controls. I have done a lot of projects with the EasyGen platform as well, my own preference with the is the backpan mounted 3500XT module, I have run into some reliability issues with the 3400XT type (front panel mount), many of the issues depending on the environment the controls are mounted in.

The EasyGen is a very capable platform, but in asking it to do everything requires an extensive amount of programming and serious shakeout during commissioning, a large number of service calls I did over the years were mainly due to configuration issues. My experience is that with fairly simple systems an EasyGen can "do it all", more complex systems require possibility of needing additional levels of protection, sequencing, remote monitoring and data collection.

Hope that helps, MikeL.

Thanks. I am a data center facility thus needing high reliability. We are closed transition to utility at 480V. These are going to be continuously rated gens - entire building is backed by gen power. No plans for solars. We do have UPS(s) throughout the facility

 

[catserveng]

Pretty simple system for a data center, at least in my experience.

The most reliable and resilient system in my opinion would be a master PLC acting as overall control of the system. I would look for a PLC system that has good availability for local support, both programming and parts. The bulk of the systems I have done used Allen Bradley PLC's from PLC5's, to SLC's to Compact and Control Logix platforms. The PLC selection is best defined by your local support abilities if reliability is a primary concern. There are lots of great PLC platforms available, but the ability make adjustments, repairs and upgrades as needed in a timely manner should be a primary driver in the selection process.

Woodward EasyGens would be a very good choice for genset controllers to do synchronizing (phase and voltage matching) and real and reactive power control. The beauty of the EasyGen platform is that you can use as little or as much of the available as you want. I would suggest you use the EasyGens as the synchronizer and load controller and reduce the amount of "extras" you have the control do. The EasyGen can be a protective relay, but if you use a controller and protection in a single device, what happens when it fails? I know this is an old school approach, but after seeing occasional out of phase close conditions during paralleling, units operating in kW overload overload conditions, or operating in excessive forward or reverse VAR conditions, I find relying on a single box for control and protection doesn't function as expected.

I would suggest SEL 700G generator protection relays, in my own experience in North America, I have found that SEL's engineering and service support is excellent, and the relays offer not only premium protection abilities, but the SER (Sequence of Event Record) and fault recording, when properly setup, provide information that can help you quickly identify the fault conditions and help you make better decisions regarding the cause of the problem.
In several projects I have done, I like to use the relays as the power metering equipment for remote display and logging and usually include relay status information to alert plant staff if problems occur.
As with PLC's, there are many good providers of electrical protective relays, so looking at service and support capabilities in your area should drive your relay selection, instead of what the switchgear provider typically uses.

Your new switchgear also needs to take into account recent changes in safety regulations, such as 70E and 70B, the switchgear and controls need to be able to be safely maintained and can be operated in both automatic and manual modes if required.

I have a long-term dislike of OEM provided "overall" controls systems, as you noted in your original post, CAT offers control systems, and in a lot of cases they work fine, but unless the local dealer has an AES (Advanced Electrical Service) group, and technicians VERY familiar with teh control system installed, you may find that when commissioning and service/repair is required, the available support may not be available. Also the software to connect and manage these systems is proprietary and a "customer" version which is available is not as capable as the dealer or factory version to make some adjustments if needed. The software and hardware required to connect to these systems can also be quite expensive and usually require a subscription requiring regular renewal to stay current.
Other OEM's have similar issues with the proprietary controls systems, so before you go that route have a frank discussion with your local dealer has to their engineering and service capabilities and do they have more than "one guy" to do more complex systems.

The above information is based on my personal experiences, I worked several years for a CAT dealer who did complex power systems and worked as a contract service and commissioning engineer for CAT in their power system and oil and gas groups. I have also done service, technical assistance and training for other OEM's and their dealers, and even though retired (almost), I still deal with your type systems regularly.

I hope you find this information helpful.

Mikel