SEL-700 is a generator protection relay with multiple CT inputs and VT inputs. It has a large variety of available metering quantities and logging available.
SEL-735 is a revenue grade meter with a single set of CT&VT inputs. The 735 has several power quality metering and event reports that the 700G will not have and it’s similar for 700G.
Most generating applications would have 700G and 735 for different reasons. The last plant I worked at had 700G&300G for gen protection and 2 735 meters - one for gross output and one for Aux load.
The big difference is the 700G is a protective relay, so if used as such it must be wired to protection class CTs. Revenue metering, on the other hand, requires revenue metering CTs.
I believe the 735 is more accurate (revenue grade) and also includes more power quality information in the metering data. It also has metering style outputs like kxy pulses and MV90 metering communication, which the 700G does not.
one thing to add is that neither is Revenue Canada approved. so you would have to get a different relay if you plan on doing revenue metering. SEL-735 would work as meter/check meter.
@maradona129508, I mean, this is the research you should be doing i dont know your location every province would have different vendors which would have different approved models. from the region I am from, there are a few but the main ones we use is the ION8650. i hear they are moving to the ION9000 series. I believe the difference is power quality features. I would contact your local ION (MCN?) supplier and ask them which ones are approved and go from there. I would get the main one revenue canada approved and the second one identical just not approved if you are concerned about cost. if the main one fails you can always send one back while using the other one as backup and / or get the second one approved etc. Keep in mind, revenue metering approved is a Sealed meter. so you have to send it back to the factory to get programmed/sealed. which usually takes a long time.
I feel like i should also mention to make sure your PT/CT is measurement canada approved. your province would dictate what %error/burden/class is the minimum requirement. be sure to get the correct one. You do NOT want to get these approved at the last minute. Revenue Canada is is NO rush ever. so you will be sitting for months.