pset 275 whole lab 3

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Prepared for: Russell K Campbell, PEProgram ChairPower Systems Engineering TechnologyCincinnati State Technical and Community college

2014

Simple Overcurrent and Reclosing Application with SEL-RTS Relay Test SystemPSET 275 Lab 3

Simple Overcurrent and Reclosing Application with SEL-RTS Relay Test System 1

Purpose:The purpose of PSET Lab 3 was to simulate sequences of a utility protection design; a normal operating scheme, and an overcurrent and reclosing application on a feeder breaker. The SEL-351S was configured to our SEL-AMS (Adaptive Multichannel Source) according to the schematic on page 2. As referenced on schematic, we chose a DC/trip/close. Three phases of 60 Hz current were connected to the relay and the breaker status 52A contact was connected to IN101 wetted with a dc voltage matching the logic voltage input rating on the relay, as instructed. For the dc control circuit, the OUT101 was connected to the trip coil and OUT102 was connected to the close coil. The current and voltage inputs from the SEL-AMS were verified as correct for this application before proceeding. The SEL-351S was programmed using the SEL ACSELERATOR QuickSet 5040 Software and the Template Guide provided for installation of the template into the computer. This allowed a programming interface with the relay. The template was loaded into the relay, after approval of design installation. After transfer of the information to the relay and confirmation of acceptance from the relay, the SEL-351S relay provided overcurrent protection for our simple overcurrent and reclosing simulation. This simulation will represent the three sequence event that the SEL Quickset Design Template provided.

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This is the SEL QuickSet Design I/O for the Lab 3 configuration. We only chose to wire the breaker in a DC trip/close circuit configuration. The breaker could have been wired in an AC trip/close configuration also.

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Relay Settings:CT Ratio: 240

PT Ratio: 180

Phase Curves

Pickup: 400 Fast Curve Type: A Fast Curve Time Dial: 1

Ground Curves

Pickup: 200 Fast Curve Type: 1 Fast Curve Time Dial: 1

Reclosing Relay: Number of reclosures: default 3 (disabled)

Here, you could set number of reclosures to N to Omit the Reclosing function. Reclose Interval 1: 2 Reclose Interval 2: 10 Reclose Interval 3: 10 Reclose Interval 4: 0 Rest Time for Auto Reclose: 30 Reset Time from Lockout: 10

Given the settings of the relay, 1.73A at terminal of the board would be a normal reading for the 240 setting on the CT, and for 480 the terminal reading would be .83A.According to the notes from the simulation, 12kv and/or 240A would work to simulate a fault condition that the relay would operate for.

The post fault condition on phase C indicated no current. We should expect this. With no reclosing function enabled, the current reading on all three phases should be zero. If one phase breaker trips and you have no reclose, you have no current in any of the phases according to American protection practices. If we have a fault in one phase, then we trip all phases to limit damage to loads and equipment. In our test, the LED for phase C illuminated after the test to indicate a fault on that phase and when investigated further, indicated no current.

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The following charts correspond to all of the available settings using the SELs Acselerator QuickSet 5030 software.

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Conclusion:In our simulation of a fault condition using the SEL-351S, the relay did not work as expected. The team encountered a password error with the system, we could not finalize the test and achieve the desired loop sequence. Although the phase C illumination on the Target LED #24 was illuminated according to team, I am not sure how many more were illuminated. From what I can tell from the manual, LEDs #12 (a trip has occurred), #14 (Relay has tripped on a fast reclosing curve), and #24 (Phase C involved in fault) should have been lit. From memory, I witnessed the middle left light illuminated, which according to the manual, indicate a remote blocked condition. I realize from this lab that the Schweitzer Engineering Labs SEL-351S relay is a very valuable and elaborate tool with which to configure any type of scenario of protection for the Utility industry and personnel. I also realize without any doubt that the multivariable programming protection scenarios present in the book seem daunting, but, with the proper training the relay protection programmer could be an interesting and admirable endeavor. Being involved in this particular segment within the Utility Industry would be more interesting than many we have covered in the program.

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pset 275 whole lab 3

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