I have designed a converter which is connected to RL type of load. I want to measure active as well as reactive power consumed by load. I did not find any block in plecslib which enables me to measure P and Q. Could you suggest me the solution?

There is not a block that will calculate P and Q for you automatically, you will need to apply this logic yourself. But we have several demo models that show how this can be done, for example the â€śMicrogrid in Island Operationâ€ť, â€śSTATCOM Cascaded H-Bridge Converterâ€ť, and â€śNeutral-Point Clamped Converterâ€ť models. I also attached a screenshot from the NPC demo model where the P and Q equations are implemented using the measured three-phase voltage and current waveforms. Let me know if you have further questions on this topic.

Hello,
What answer are you expecting? Note that the waveforms for P and Q are cyclical and vary quite a bit peak-to-peak. You should consider using a Periodic Average block with an averaging time of 1/f to get the mean P and Q values. Does this help?
Regards,
Kris