Last week, one of our clients sent us some questions about the output of our Distribution System Loss Segregator (A.K.A DSL Segregator), which currently, on the second stage of its development.

Here is one of their observation;
One of their feeders has around 1,800 KVAR of shunt capacitors installed in three parts of the primary distribution line. Initially, base on the output of the Segregator, energy losses at the primary line is around 460 Kwh. However, when they removed the capacitors, they noticed that the energy loss decreases to 390 Kwh. This is disturbing because the effect of that change is opposite to what should be expected, that is, increase the losses because the capacitor that was removed was intended to supply Kvar that helps in decreasing losses in the line. Thereby, according to them, removing capacitor compensation should go back into a higher loss system.

Does this mean that the DSL Segregation Software is inaccurate on its computation?

Well, let us first analyze the problem before proceeding into a conclusion.

Actually, the observations and theory are all correct. But they missed out to make further experiment to explain the scenario. My initial theory and reason why the losses decrease when the capacitor was removed is that, there exists an overcompensation on the initial configuration of the system.

To prove this theory, we re-run the system, in this case, we only decreased the amount of capacitor compensation installed to 900 Kvar. And the result was, a primary line loss of 320 KWh. And I think that it is more than enough to prove that there exists an overcompensation in the initial configuration of system.

Let us summarize the result;

Case 1: Capacitor installed = 1800 KVar; Loss= 460 KWh
Case 2: Capacitor installed = 0 KVar; Loss = 390 KWh
Case 3: Capacitor installed = 900 KVar; Loss = 320 KWh

If no capacitor was installed, the loss was 390 KWh. If 900 KVar of capacitor was installed, the loss decreased by 70 KWh. However, if the capacitor installed was doubled to 1800 KVar, instead of further decreasing the loss, what was happened is the opposite.

Conclusion
Installing a capacitor has numerous benefits, primarily, decreasing losses. But installing a capacitor is definitely not as simple as you just put a capacitor on a system. It must be installed in an optimal matter, that is why there are lots of research on optimal capacitor placement, including my undergraduate thesis. This is because there are 2 primary drawbacks in not optimizing capacitor placement. 1.) You might not benefit from your investment because the loss reduction is minimal, and 2.) Instead of reducing losses, it further increases due to overcompensation.

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