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APP 411L: 87L Functions in the SEL-411L Relay


This course is intended for utility and industrial transmission protection engineers and power system consultants who want to understand the line current differential (87L) functionality in the SEL-411L Line Differential Protection, Automation, and Control System in detail.

APP 411L is an advanced hands-on course that builds on the introductory configuration and protection principles taught in CBT 101, CBT 421, and APP 421 and on the logic configuration principles taught in CBT 104. Students in APP 411L will complete hands-on exercises to configure differential protection and advanced logic. SELogic, distance elements, directional elements, etc., are not covered in this course; students interested in learning about all functions other than 87L should take APP 421 or APP 411L in conjunction with APP 421.


Day 1
  • Introduction
  • Example System One-Line Diagram and Parameters: Two-Terminal, 345 kV Line Example
  • Introduction to SEL-411L Relay Communications and acSELerator QuickSet SEL‑5030 Software
  • SEL-411L Setting and Applying 87L Line Differential Elements Hands-On Exercise
  • SEL-411L Channel Requirements: Logic, Master, Slave, and Loss of Protection
  • SEL-411L Communications Channel Verification Hands-On Exercise
  • SEL-411L Metering Test Hands-On Exercise
  • 87L Element Logic
  • Three-Pole Trip Logic
  • SEL-411L Internal Faults Hands-On Exercise
Day 2
  • Theory of the Generalized Alpha Plane
  • Disturbance Detection Logic
  • External Fault Detection Logic (includes a hands-on exercise)
  • Testing the SEL-411L: 87L Test Modes
  • Data Alignment, Clock Offset Calculations, and Time-Fallback Logic
  • Channel Monitoring, Alarming, and Hot Standby Logic
  • User-Programmable Communications Bits and Reports
  • SEL-411L Setting and Applying 87L Line Differential Elements for a Two-Terminal, Two-Channel System Hands-On Exercise
  • SEL-411L-1 Fault Location Methods and Settings

Course Objectives

At the conclusion of this course, students can:

  • Navigate acSELerator QuickSet SEL-5030 Software
  • Identify settings calculation formulas and terminology for 87L applications
  • Determine effective line differential protection settings for example systems
  • Configure 87L for serial and Ethernet applications
  • Create SEL-411L Relay logic equations for 87L protection functions
  • Monitor system performance with real-time metering using HMI tools
  • Test 87L protection schemes and verify proper relay operation
  • Retrieve and analyze events using COMTRADE files and the Sequential Events Recorder (SER)
  • Configure traveling-wave fault location

Course Requirements


Before you attend this class, you must meet the following requirements:

Course Preparation

Please check the General Course Information page for what you should bring to class. In addition, please make sure that the laptop you bring to class has the following software/features:

acSELerator QuickSet SEL-5030 Software with the SEL-411L driver and instruction manual, installed and updated through SEL Compass

Course Information
Course Base Fees: USD850*
CEUs: 1.4
  • Transmission Line Protection Track - Elective
Available Courses
Phoenix, Arizona, USA
November 14–15, 2017

3050 West Agua Fria Freeway Suite 240
Phoenix, Arizona 85027

Additional Information:
8 a.m.–5 p.m. each day

Recommended Hotel Information:

Hilton Garden Inn
1940 W. Pinnacle Peak Rd.
Phoenix, AZ 85027
Amenities: Complimentary internet, on site restaurant, complimentary parking

Homewood Suites Phoenix Happy Valley
2470 W. Charlotte Dr.
Phoenix, AZ 85085
Amenities: complimentary breakfast and light dinner. complimentary internet, complimentary shuttle within 5 miles of hotel, complimentary parking

Courtyard by Marriott
2029 W. Whispering Wind Dr.
Phoenix, AZ 85085
Amenities: Complimentary internet, on site restaurant, complimentary parking

Hampton Inn
2550 W. Charlotte Dr.
Phoenix, AZ 85085
Amenities: complimentary breakfast, complimentary internet, complimentary shuttle within 5 miles of hotel, complimentary parking

*Please note that these are only recommendations


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