Modelling Generators in Parallel- Reg

More information is required. Are the two generators the only sources or is the network also attached to a grid or other local sources? When you said "PV mode" did you mean "PF (Power Factor) mode?

Time to RTFM (Read The Fine Manual) because the program is doing what you asked it to do, but in real-life two closely coupled generators require some form of "cross current compensation" to ensure that they share the reactive load properly. Having one on PFC will fix its reactive output relative to its real power output and force the other machine to provide the reactive power (+ or -) to support the loads' requirements.

Thanks RamConsult...

There are no additional sources or Grid. We have just 2 DG set in parallel.

PV mode - Voltage control mode.Here we give the Min/Max reactive Power & the KW.

PQ mode - Real Reactive mode, mainly for load bus.

I understand...

GENERATOR SET-KW & KVAR LOAD SHARING (IN A PARALLELED SYSTEM)

LOAD SHARING

Load sharing is defined as the proportional division of the kW and kVAR total

load between multiple generator sets in a paralleled system.

Load sharing is essential to avoid overloading and stability problems on the

systems' generator sets.

ACTIVE POWER (KW) LOAD SHARING

When generator sets operate in parallel, the engine speed governor of each

generator set determines the proportional sharing of the total active power

requirements (kW) of the system.

The kW load sharing is achieved by increasing or decreasing fuel to the

systems' engines.

As the fuel to the engine of one generator set in a group is increased it will not

lead to an increase in speed and hence frequency (as it would if it were

operating alone) but it will lead to an increase in the proportion of the total kW

load that it will deliver.

As the fuel to the engine of one generator set in a group is decreased it will not

lead to a decrease in speed and hence frequency (as it would if it were

operating alone) but it will lead to a decrease in the proportion of the total kW

load that it will deliver.

The control system of the generator sets (via the engine speed control system)

monitors and controls the sharing of the total kW load in proportion to the

relative rating of the engines on the systems' generator sets.

Created by J.M.J. Lloyd Uncontrolled once printed

REACTIVE POWER (KVAR) LOAD SHARING

When generator sets operate in parallel the alternator field excitation system

of each generator set controls the proportional sharing of the total reactive

power requirements (kVAR) of the system.

The kVAR load sharing is achieved by increasing or decreasing the field

excitation to the systems' alternators.

As the field excitation of one generator set in a group is increased i.e. overexcited

it will not lead to an increase in voltage (as it would if it were operating

alone) but it will lead to an increase in the proportion of the total kVAR load it

will deliver and a decrease in its power factor.

As the field excitation of one generator set in a group is decreased i.e. underexcited

it will not lead to a decrease in voltage (as it would if it were operating

alone) but it will lead to a decrease in the proportion of the total kVAR it will

deliver an increase in its power factor.

An undesirable circulating reactive current (cross current) will flow in the system

if the excitation of the alternators is not matched.

The voltage control system of the generator sets (via the alternator voltage

control system) monitors and controls the sharing of the total kVAR load in

proportion to the relative rating of the alternators on the systems' generator

sets.

My question is that, will this software can not control automatically the KW/KVAR ob PV mode as a part of simulation?

Remember that when you run a load flow, you are essentially solving for four quantities at each bus/branch, i.e. voltage, voltage angle, active power and reactive power. At each source or load, you need to specify at least two of these quantities and the load flow will solve the rest.

So when you set a generator as a PV element, then you are specifying active power and voltage (magnitude). When you set it as a slack element, then you are specifying voltage and voltage angle (which is why it will take up the "slack" and cover any active or reactive power imbalances).

Basically, what I'm trying to say is that the PV elements will output the power dispatch that you set it (while trying to maintain the voltage to the preset value), and the slack element will cover any imbalance. If you want to set up load sharing and reactive power control, you will need some external controllers.

I'm not that familiar with PTW, but other packages have an external controller option for load flows where you can set the amount of load and VAR sharing.

Thanks Juleselec. You have answered my query. Thanks.

SKM PTW doesnt have controller. So manually we set VAR & Kw.Thats right.