I'm currently having a reverse power warning issue with the generator. I have also read many posts on the forums. They all say that the cause is because the motor does not provide enough torque for the generator, so the generator receives current from another generator or the grid. But now I only have 1 generator, completely disconnected from the grid but still having the above situation. I don't know where the reverse current comes from going into my generator. I don't know if it's related to the load using the inverter, because with the same current the generator will still work with the same current. other equipment, but with the device using the inverter, the error.
Hope everyone can help.
Thanks everyone.

 

I'm currently having a reverse power warning issue with the generator. I have also read many posts on the forums. They all say that the cause is because the motor does not provide enough torque for the generator, so the generator receives current from another generator or the grid. But now I only have 1 generator, completely disconnected from the grid but still having the above situation. I don't know where the reverse current comes from going into my generator. I don't know if it's related to the load using the inverter, because with the same current the generator will still work with the same current. other equipment, but with the device using the inverter, the error.
Hope everyone can help.
Thanks everyone.

What kind of prime mover is it ?

What you mean by receive current... Reverse power or low forward power is not well understood as you explained it here..
What does you mean by :
Because with the same current the generator will still work with the same current. other equipment, but with the device using the inverter, the error. its (it is not really clear).

Please devellop better on what I am asking here so we can support remotely..

Also can you provide Prime mover governor /control system ...& AVR/Generator OEMs

 

danghieu153,

Nearly ALL of the generators being discussed on threads on Control.com are three-phase generators being driven either by large diesel motors or combustion turbines--and as such all are primarily full sine-wave outputs.

It would seem your question is regarding a small, single-phase generator probably driven by a small gasoline engine with an inverter output, and when you try to connect something to the unit's inverter output you get a reverse current warning. Is that correct?

Many small single-phase generators DO NOT have the neutral of the outputs bonded (connected to) to the earth (ground) output, and unless they are connected to an earthing (ground) rod driven into the earth they will struggle to work correctly, especially in inverter output mode. A very simple "bonding plug" can be constructed to bond the neutral output to the earth connection (without using an earthing (grounding) rod pounded into the earth).

Please provide details of the generator and prime mover you are working with (single-phase; three-phase; type of prime mover; types of loads being connected to the generator output(s) (electronic; synchronous or induction motors; lighting (halogen; LED; flourescent; etc.)--UNLESS you are referring to large (hundreds or thousands of kW/MW) three-phase generators, in which case you would need to provide more information about the prime mover, the prime mover control system, the generator excitations system, the nature and size of the load(s) being connected to the generator, etc.

PRESUMING the generator you are referring to is a small, reciprocating engine-driven single-phase generator, it is entirely possible there is something amiss with the current sensing device (connected incorrectly, or "in reverse") which is causing the issue. But, it's more likely the neutral bonding that's causing the problem. You can use your search engine to find all kinds of articles and YouTube videos about neutral bonding devices for small engine-driven single-phase generators.

Best of luck!

 

Thank you two.
Currently I am using a generator with model code AGG C1100E5 380V 1000 kvA. This is a 3-phase diesel generator. The control device is DSE8610. Currently I only use a few types of devices such as:
+ Pump for fire fighting.
+ Cooler with large capacity.
+ Other common devices.
I tried with pump and the generator is working fine and no problem. But when I use the cooler, the generator immediately gives a reverse power error even though I see the current displayed on the new DSE8610 is only 50A and I haven't fully turned on all the coolers. Currently I only use 1 generator and the grid is completely cut off when the generator is turned on. Hope you can give me some advice.

 

Thank you for the details

My first impression is that DSE8610 IS NOT SETTED/TUNED CORRECTLY to get the unit a proper & smooth operation....

As it is used for load sharing i thinks that they could be a load (reverse power ) when connecting to the load bank ( in island mode not connected to the grid)

The unit is not stabilizing Frequency also ..thats why you get a " power return " called reverse power..

Can you tell us about frequency regulation in that island mode operation ..is the frequency ok ( I mean well regulated )

What about Load ...do you see kind of Load fluctuations ( +/- ) when coupled the unit with the load that you described?

Question:
Was the unit operating correctly before ( no reverse power in that configuration of island mode)?

My Advise would be to get that DSE8610 TUNED ACCORDING TO THE LOAD BANK.
Thank you for your answer

James

 

There are all types of coolers. What type of cooler are you referring to? A large water-to-air heat exchanger with induction motor-driven fans and induction motor-driven pumps? Is it a chiller-type cooler with induction motor-driven compressors?

And, as ControlsGuy25 asked: What is happening to the frequency when the cooler is being operated? Is it stable, or is the frequency oscillating?

How long has this diesel-generator been in service since commissioning? Has it ever been working correctly? Is this something which just started recently—after some maintenance outage? If so, what work was done during the maintenance outage?

When the generator is being operated independently of the grid, what mode is the diesel governor being operated in: Isochronous Speed Control or Droop Speed Control? Is there any external load or power management system trying to control frequency when the diesel-generator is being operated independently of the grid?

Can you see what the power factor of the generator output is when the cooler is running—and can you tell us what the power factor of the cooler is when being driven by the diesel-generator?

I’m sure you don’t like reading or answering all these questions—but we don’t know precisely what is happening and if something has recently changed. Has any maintenance or repair been performed on the generator excitation system? If so, what?

I’m sure you’re looking for one or two sentences about what is causing the issue and what to do to fix it, but you haven’t given us enough information to be helpful. Without understanding more about the cooler and how the diesel-generator is operating when powering the cooler we can’t really offer too much more help. We thank you for the information you have provided, but we need more.

Help us to help you by providing more details. It’s possible the diesel governor is not in the correct mode (of speed control). It’s possible the load is increasing too fast when the cooler is being operated and the diesel governor is not properly tuned to respond quickly without over- or under-shooting (could be as simple as a dirty fuel filter or a worn governor actuator or a fuel rack which is misadjusted). It could be a worn governor mechanism or dirty hydraulic fluid (if the governor actuator is hydraulically actuated).

We also don’t know what you have done to try to resolve the problem—and most importantly, what the results of your efforts were (other than there’s still a problem).

If you can providemore information we can probably offer some suggestions about how to proceed. But without any more information we can’t say with any degree of certainty what the root cause of the problem is or might be. The questions should give you some idea of the various possibilities.

Best of luck! Please write back to let us know how you fare with resolving the problem!

 

- Sorry but we're not allowed to test the customer's cooling system so I'm not sure about it.
- The frequency of the generator is stable and there are no abnormal signs.
- We have tested the generator at the factory after receiving the goods from the manufacturer with a resistive load and it works normally. But after installing the generator into the customer's load system, it immediately failed, and could not be run once. I found that if the load is small, the generator will still run, but it seems that when the load is increased, it exceeds the reverse current of the generator, so it immediately fails.
I am not sure about the current speed regulation mode of the generator. Currently I use an ATS cabinet to choose between generator and grid, which will then be attached to a load distribution cabinet.
- I can't check the power factor of the generator, I plan to check its parameters next time because I can't connect the generator to the manufacturer's software yet.
- The generator is brand new from the manufacturer and hasn't been repaired yet so I'm not sure if the excitation system has a problem.
- I think it's not the reason the load increases so quickly, because I slowly closed the load and when it increased to 50A, it failed, it was too small compared to the capacity of the generator.
Thank you for your support.

 

Looking at the controller on the internet the default reverse power alarm is 35KW which would about correspond to your 50 amps. Since it worked at the factory I am assuming that the sensing CTs are part of the generator skid at did not have to be disconnected and then reconnected at sight. I would double check anyway. The drawing appears to have polarity towards the generator and the secondary polarity at the non-commoned inputs of the control unit. Don't see how it could have worked right at the factory if it was wrong but I'd still check to be sure.

 

It certainly seems like something is amiss with the CT (Current Transformer) wiring and/or circuitry. If the polarity is not correct then as load is increased and the current increases it will be detected as being in the wrong direction (“reverse” current) and trigger the alarm, usually opening (tripping) the generator breaker. CT—and PT (Potential Transformer)—polarity should always be tested when installing and commissioning a new generator because they are critical to protection of the generator and the prime mover (the diesel engine in this case).

“…But after installing the generator into the customer's load system, it immediately failed, and could not be run once. I found that if the load is small, the generator will still run, but it seems that when the load is increased, it exceeds the reverse current of the generator, so it immediately fails….” This statement is very confusing, but it could just be a translation issue. As MWO wrote, if the CT polarity is incorrect then as the load (current) increases it will exceed the reverse current setpoint and (usually) trip open the generator breaker to protect the prime mover (diesel engine). This tripping open of the generator breaker could be the failure you are describing…?

As you noted in your original post reverse current is caused by the prime mover not being able to produce enough torque to keep the generator running at rated speed (frequency) so current flows from the grid to the generator (instead of from the generator to the grid) and thereby the generator operates like a motor—spinning the prime mover (the diesel engine in this case), which can damage the diesel engine and/or the coupling between the diesel engine and the generator. So, the reverse current function serves to protect the generator’s prime mover by tripping open the generator breaker.

If there is no other generator (and prime mover) connected to the diesel -generator then either the load can produce current (highly unlikely!) or the CT wiring is incorrect or the reverse power sensing function is … screwed up, not likely, but stranger things have happened.

Again, get that CT circuit checked out—and soon. And the PT circuits, too—because they are all critical to the diesel and generator protection. It could be as simple as two wires being crossed (terminated improperly) at a terminal board (or four or six wires for a three-phase system). Flashing CTs and PTs to test for polarity is pretty easy, especially if there is no grid power in the switchgear. And if the polarity is not correct then problems exactly as you seem to be describing will occur.

Please write back to let us know what you find!

 

Thank you for your information. I will check for problems that may be faulty. If there is information I will update again later as I cannot work with generators right now.
Thank.

 

danghieu153
Please provide a Block Diagram, or Single-Line-Diagram of the interconnected electrical components.
Regards, Phil Corso

 

Since in a AC system you cant actually measure current flow (it alternates every cycle) the reverse power is measured by monitoring the current phase relative to the voltage. In normal systems you have a lagging current (lagging power factor). When the generator is asked to receive power, the power factor and current are leading.
But this condition can be created on the system by having system overcompensated by too many capacitors on the system. This is done when customers are power for "amps" consumed and not power consumed.
Perhaps the cooler motors are overcompensated

 

Thank you for the details

My first impression is that DSE8610 IS NOT SETTED/TUNED CORRECTLY to get the unit a proper & smooth operation....

As it is used for load sharing i thinks that they could be a load (reverse power ) when connecting to the load bank ( in island mode not connected to the grid)

The unit is not stabilizing Frequency also ..thats why you get a " power return " called reverse power..

Can you tell us about frequency regulation in that island mode operation ..is the frequency ok ( I mean well regulated )

What about Load ...do you see kind of Load fluctuations ( +/- ) when coupled the unit with the load that you described?

Question:
Was the unit operating correctly before ( no reverse power in that configuration of island mode)?

My Advise would be to get that DSE8610 TUNED ACCORDING TO THE LOAD BANK.
Thank you for your answer

James

Original poster must manifest himself and give an update on this thread , otherwise we can consider that the issue is solved and so we can close the post


I don't like kind of behavior here which seems to be more and more frequent...

This forum is not dedicated to such behavior

A bon entendeur

 

According to my thoughts, Reverse power generators are popular for people who want to generate electricity. This generator allows you to use the energy produced from your solar or wind turbine system back into the grid instead of exporting it. By doing this, you can effectively “spend” your excess energy and earn money off of it while reducing your carbon footprint. Reverse Power Systems come in manual and automatic varieties and typically require minimal installation time. Once installed, they will start generating electricity immediately, allowing you to avoid those long wait times for peak billing periods.

 

[U]Amitbajpayee[/U],

A generator is an electrical device for converting torque into amperes. A prime mover (a reciprocating engine; a combustion turbine; a wind turbine; a hydro turbine; etc.) provides torque to a generator rotor. When the generator is connected to a load or loads amperes flow out of the generator--often called "forward power" for lack of a better term. It's "positive power" that exits from a generator set (a prime mover driving a generator). This thread was about a generator set--a prime mover driving a generator that is used to supply amperes to a transmission and distribution system (often called a grid) to which loads (electric motors; televisions; tea kettles; electric stoves; etc. (remember: things like electric fans and refrigerators and air conditioners are all powered by electric motors, as are pumps used to move clean (potable) water as well as dirty (sewage and effluent) water). It used to be that the largest consumers of electrical power (amperes) were water pumps (their motors, actually), but in some parts of the world air conditioners have supplanted water pumps as the largest load on electric grids.

An electric motor is a device for converting amperes into torque. Water pumps are driven by electric motors that convert amperes into torque to create pressure and flow. Electric motors are used to power elevators and lifts and cranes. Electric motors are used to move refrigerant in refrigerators and air conditioners (driving pumps). Computers and computer monitors use "virtual torque" and create "virtual work" using electricity (usually AC (alternating current) converted to DC (direct current)).

But, the fact is that the motors are really driven by the generators--and electricity is just a medium for transmitting torque from a place where it is available or can be produced to a place where it is needed. Just think of a hydraulic system--it uses a pump (driven by an electric motor) to produce high pressure and flow in pipes and hoses and that high-pressure flow is then used to do work by hydrauic actuators (usually cylinders and pistons pushing and pulling). Automatic automobile and truck (lorry) transmissions are nothing more than hydraulic pumps--driven by the vehicle's engine--that push fluid to a hydraulic motor that is used to drive the wheels. In the early days of the industrial revolution there were water wheels that had long shafts to which large leather belts were connected and those belts drove looms to create linens and textiles. These factories were located next to large rivers with large flows, and the water wheels produce the torque to turn the shaft that ran through the factory and the leather belts transmitted the torque from the shaft to the looms in the factories.

When electricity came on to the scene the largest sources of energy to produce torque were still rivers, so the first very large electrical power plants were located near large rivers or falls, and the electricity that was produced by the generators converting torque from the hydro turbines coupled to them into amperes was transmitted over wires to factories that used the amperes to power electric motors that drove the looms and processes in the factories. When boilers and steam turbines became more common power plants could be located just about anywhere that coal could be transported.

Still, power flowing "out" of electric generators is "forward power", positive power. And, still, electric generators really do the work of the electric motors and such that the amps they produce are consuming. Electricity is just a way of transmitting torque and energy from a place where it is plentiful to a place where is needed--using wires.

It shouldn't surprise you to learn that the only real difference between a motor and a generator is the direction of current flow and torque flow. Torque flowing into an electric machine and amperes flowing out of an electric machine makes the electric machine a generator. Amperes flowing into an electric machine and torque flowing out of an electric machine makes the electric machine a motor. Well, when a generator set (a prime mover coupled to an electric machine which primarily serves as a generator converting torque to amperes) is incapable of producing sufficient torque to keep the electric machine spinning at synchronous speed (the speed the electric machine runs at to produce current at the same frequency as the grid it's synchronized (connected to)) then amperes begin to flow into the electric machine (the generator) and it then becomes a motor, and it actually starts to drive the prime mover. Some prime movers don't like being driven--not at all. And they can be very seriously damaged or even destroyed by this phenomenon. This is called "reverse power"--because amperes are flowing into the generator turning it into a motor.

So, what you are thinking of as "reverse power" isn't what everyone else in the field of electricity production and consumption is thinking of. This is a technical field--and words and terms are very important if you want to be able to communicate with others without causing a lot of confusion. You may have come up with a way to think you understand what your are talking (writing) about--but it's not correct. On a very high level, it's sort of correct--but, it's so wrong that it would take a book to try to explain it. And, I've already probably run out of characters (there's a limit on the number of characters in posts on control.com...!) so I'm not going to try to go any further with this reply--except to say that you need to reconcile your thoughts with the rest of the physical world, and get your words and terms straight. Good try, but you got a lot of learnin' ahead of you. Don't let that stop you--it's necessary to mull things over and come to a proper understanding. It's a journey--and you've just begun.

 

I had gotten a data from generator. I will show a few image what i think its a cause. If you need others information, please tell me.

 

Its never too late to reply !

 

sORRY BUT i DONT SEE THE RESERVE POWER Software Parameters Configuration..

Can you share it ...

 

2 more questions:

Why dummy load control & Load shedding control are not enabled and adjusted ? is that ok for you?

 

What is the device with 16 pins on the left bottom of the single line diagramm is used for ?? with letters D L C J A H K F ,,...