DSLC Load control Problem

Check the CT connections and the CT ratio setting.

Does the meter use the same CT's as the DSLC? If not, one set of CT's could be miswired, or incorrect ratio. If both devices use the same CT's, check the calibration on your wattmeter (you said you.

There could also be additional load seen by one CT set but not the other (exciter, ancillary system loads, etc.). It might be helpful to know the size of the genset - is 200 KW 10% or 0.1% of total load? On a larger unit, 200 KW may be within the tolerance limit for your instrumentation.

Genset size is 3670 KW. When set load 3300 KW, panel shows 3600 KW.

9% is well beyond acceptable tolerance.

Before I go too far in troubleshooting, is the panel meter a direct-reading device (current & voltage inputs) or does it use a milliampere signal from the controller to drive the display? This may be a simple case of the panel meter or the current amplifier being out of calibration.

If the panel meter is direct-reading, I suggest comparing the wattmeter & DSLC input currents & voltages on each phase. You can use a clamp-on ammeter for the currents and a digital voltmeter for the voltages. If the inputs are not very close to identical, the problem is not in either device. Inspect the input circuitry for problems. If the inputs are nearly the same, one of the devices is out of calibration.

But I could not set the full load. I checked the CT ratings, CT ratio and CT phase current, and found ok. I found some manu in DSLC Hand Programer.

a. 4 mA remote load

b. 20 mA remote load

c. Reference load

d. Active load

e. Remote load input

4 mA remote load set to 0 KW, 20 mA remote load set to 3732 KW. When I set 3100 KW in the control panel then remote load input found 18.5 mA and load referece found 3400 KW and active power found 3300 KW.

At 18.5 mA the DSLC load reference should be 3452 KW. DSLC give the correct Load reference, I think.

Then I checked other two gensets. At the moment of checking they were running with 3300 KW load and load reference near 3300 KW and remote load input of DSLC found 18.37 mA & 18.25 mA.

Is my control panel output signal, which is input to the Remote Load Input, higher than what it actually should be?

And for your information, my panel meter shows the load which i found Active Load on DSLC Hand Programer.

Is the problem in my control panel. For your kind information, my genset was shutdown for One Year.

For the values you provided, a 3100 KW remote load setting should give a remote load input of 17.29 mA. [(3100/3732)*16 mA]+4 mA = 17.29 mA; where 16 mA is the range and 4 mA is the offset. The 18.5 mA remote load input should cause 3382 KW of load [(18.5-4)/16]*3732 KW = 3382 KW, which is close to the active power and load reference values you saw.

The 1.21 mA control panel error is more than 7.5% of of the 16 mA signal range, and appears to be the cause of your problem. It appears that whatever is generating the 4-20 mA signal for your remote load setpoint is not calibrated the same as the DSLC. Recalibrate the source device, checking at least four evenly spaced points across the entire range of the instrument. I usually do 5 points at 0, 25%, 50% 75% & 100% of range.

Your calibration should end with the following results:

I found, my DSLC remote input come from PLC. Is that possible to callibrate my PLC system?

Yes. You'll need to access the PLC program and look at what tells that output to produce a given signal. I suspect there is either a programming error (probably a scale factor on the input or the output), or the input device which tells the PLC what load the operator wants is faulty.