DG Synchronization Panel: What Every Engineer Should Know

Your second generator is now online. But is it really ready to interface with the live bus? It is here where operating a generator becomes an engineering task, and not just a case of starting and stopping. When there are several DG sets fitted in an industrial plant, the extra generating capacity is provided by these DGs, but these generators cannot simply be coupled to each other when there is a need for extra electricity. They need to be synchronized and coupled in the right electrical environment and managed such that the load is shared as intended. And this is the job of a DG Synchronization Panel.

Why Does a Plant Need DG Synchronization?

Imagine a factory, where DG-1 was running the plant during a utility power loss. There is an increase in production demand, and DG-1 is insufficient to meet this demand; therefore, DG-2 is instructed to start. However, the engine starts, but the breaker must not close at once. For parallel operation of DG-2 with the live bus, there needs to be verification by the synchronization system that the electrical conditions needed are within the set parameters. This usually includes voltage, frequency, phase sequence, and phase relationship.

The process flowchart would look something like

Load Demand → DG Start → Synchronization → Breaker Closing → Load Sharing This process could be automatic, but there is control logic, sensing, and protection designed in it.

Synchronization Is More Than Matching Frequency

An error commonly made is believing that since the frequencies are the same, the generators are synchronized and can be run together. Generator synchronization consists of more than one electrical condition. Both the incoming generator and the bus that is live must meet the conditions that the system sets for synchronization. That is why a well-designed DG control panel must have more components than a controller and breaker.

The key engineering challenge here is not

“Can we close the breaker?”

It is

“Under which exact conditions should the system let the breaker to close?”

The Real Challenge Starts After Synchronization

Connecting generators to the same bus becomes just one half of the process. When DG-1 and DG-2 are in parallel, the next stage is automatic load sharing. Take the situation where DG-1 carries the major share of the load and DG-2 takes the minor share. It is not guaranteed that merely by connecting the generators, the loads will be shared as planned within the plant. An effective generator synchronization system will take into account the loading of the generators depending on the design of the system and its generators. However, now let us imagine that the demand for production has decreased sharply. Is it really needed to have all DGs working in such conditions? Depending on the policy of operation, the automation system can be arranged in such a way that the unneeded generator will be unloaded and taken out of operation when necessary. On the other hand, growing demand will start the proper sequence of operations of additional generators. Thus, the synchronization system becomes responsive to the real load of the plant.

What Happens When Something Fails?

Here is where engineers should take notice. A good synchronization scheme cannot be devised only for perfect operational conditions.

These questions should be posed

What if DG-2 fails to start up? What if synchronization conditions are not fulfilled? What if the breaker does not close in response to the command? What if one DG in operation trips? What if communication with the generator controller is lost? The answer to this will depend upon the application but some abnormal conditions should be considered by engineers. Provisions such as protection, alarms, feedback from breakers and electrical and software interlocks can prevent any wrong operation and provide useful information to the operator. Good industrial automation is about controlling what must happen. But more importantly, it is about controlling what must not happen.

Why Two Similar Panels Can Perform Very Differently

Put together two DG Synchronization Panels next to each other and you might think that they are nearly the same. However, there can be vast differences in their performance. And that is due to the Control Philosophy. Before designing the panel, an expert in electrical panel manufacture should have all information on DG ratings, alternator and controller specifications, single line diagrams, breaker arrangement, load profile of the plant, protection requirements, start-stop priority, operation mode, communication requirements and any future expansion plans. High-quality components will not fix bad logic. Effective synchronization engineering begins with the plant, not the panel.

A Better Way to Select a DG Synchronization Panel

Not just price and brand comparisons of component quotations should determine your decision, but ask the manufacturer about the operational sequence. Inquire: What are the pre-breaker closure checks performed? How is load-sharing control performed? What happens if there is no synchronization? What is the priority of DGs? What is the list of alarms and interlocks? What is the action taken on decreased plant demand? Is there a possibility of adding other generators in future?

Then conduct one simple buyer’s test

Inquire the engineer about the operational sequence from loss of mains to multi DG operation, followed by the sequence after the failure of one DG. If the sequence has been properly engineered and is intelligible to you, then you are buying a system and not just a collection of components in a box.

The Panel Should Think Before It Acts

DG Synchronization Panel boils down to controlled decision-making at the end of the day. It helps decide when an additional generator is needed, confirms its readiness for connection, synchronizes breaker operation, controls load sharing and monitors post-operation. At HEAL Engineering Systems, Ghaziabad, we manufacture DG synchronization panels, electrical control panels, PLC panels and industrial automation systems depending upon the requirement. HEAL Engineering is also listed on Google Maps and Google Business Profile. So, before asking “How many DG sets can this panel synchronize?”, ask the more important engineering question:

“Does the system know how to react in case of changing operation conditions?” This is where synchronization goes beyond just an option—it becomes a solution.

Frequently Asked Questions

1. What is a DG Synchronization Panel? A DG Synchronization Panel is a control system for synchronization of generators operating together in parallel. The panel can be configured depending on the application to perform various functions including checking for synchronization conditions, controlling generator breakers, load sharing, start and stop routines, etc.

2. Why is automatic load sharing essential among DG sets? Automatic load sharing helps in distributing electrical load among generators based on their design specifications and capabilities.

3. What information is needed prior to the design of a DG synchronization panel? Engineering input includes ratings of DGs, alternators and controller information, one line diagram, breaker information, load profile, protective information, operating philosophy and future needs.