Design and Installation
Utility Interconnection
Electrical Distribution

Interconnection of Utility-Scale Solar PV to Distribution

by Tim Taylor • Last updated 06/2022

5.0/5 (view ratings)
13 students
9 modules
16:10 hours
129 assignments

Course description

This course is approved for IEEE 2.4 CEUs/ 24 PDHs as well as NABCEP CEUs.

Understanding utility distribution systems and utility requirements for Solar PV connections to the utility grid takes a special but essential knowledge base. The developer or engineer needs a working knowledge of:

  • IEEE Standard 1547-2022
  • Medium-Voltage Lines and Substation Equipment
  • AC Overcurrent Protection
  • Fuses, Reclosers, and Circuit Breakers
  • Step-Up Transformer Winding Connections and Ratings
  • Volt/VAr Control and Power Factor
  • Differences Between Transmission and Distribution
  • Unintentional Islanding
  • Inverter Control Modes
  • Hosting Capacity for Feeders and Substations
  • Ground-Fault Over-voltage (GFOV)
  • Effective Grounding and Grounding Transformers

Why Take This Course
This course provides solar PV and electric utility professionals an understanding of utility distribution systems, and the considerations in connecting utility-scale solar PV to distribution systems.

What You Get
This course has been designed so that you will:

  • Get a thorough understanding of the considerations and criteria for successful interconnections of utility-scale solar PV to utility distribution
  • Become conversant in the language and concepts of utility distribution systems, and have better conversations during solar PV project development and execution
  • Become more valuable to your organization, and enhance your career progression in the connection of utility-scale solar PV to utility distribution

What You Can Expect
The course is technically-oriented and focused on electric power concepts, equipment, and applications. However, the material is presented from the “ground-up”, so that if you are a non-engineer or are new to utility-scale solar PV plants and utility distribution systems, you can progress easily through the content with little trouble.

Visual Learning
Extensive use of graphics is used in the instructional videos, and you can download a copy of all class material for future use.

In this course, Tim Taylor, Owner of Electric Distribution Academy, brings his 30+ years of experience in utility distribution systems, utility-scale solar plants, and interconnection requirements to give students the background to succeed in the growing utility-scale solar PV industry.

Tim provides an extensive list of resources that you can use in the future for more in-depth conversations on key topics.

Tim is readily available through the class discussion board, and holds periodic office hours.

In preparation for this course students should take Tim's free course "Overview of Electric Distribution Systems"

Next Live Meeting - August 18, 2022 at 12pm Eastern (USA)

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Continuing Education Units

Approved for: NABCEP Advanced Credit Hours, NABCEP NEC, NABCEP JTA, NABCEP PV Associate Renewal, 2.4 IEEE CEUs.

Approved NABCEP CEU Hours
NABCEP Credential Advanced Hours for Exam Recertification CEU Hours NEC JTA RE Elective Building or Fire Code
17 24 0 17 12 0
0 12 0 0 0 0
17 24 0 17 12 0
17 24 0 17 12 0
17 24 0 17 12 0
17 24 0 17 12 0
NABCEP Registered Provider

This course counts towards the training requirements for taking NABCEP professional certification exams and CEUs for renewing all certifications.

Get NABCEP Certifications

Full course outline

Module 1 - Welcome - Orientation Materials

  • Course Introduction from Tim (11:44 minutes)
  • Class Launch Video (01:47 minutes)
  • Next Live Meeting - August 18, 2022 at 12pm Eastern (USA)
Module 2 - Generation and Transmission Systems

The overview of Generation and Transmission systems provides context around utility-scale solar interconnections to T&D systems. This week we take a look at the different types of generation on utility systems, including central station (steam) thermal types of generation; an overview of the different types of renewables generation; and a discussion on utility transmission systems, including concepts, architectures, and operating principles.

  • Lecture 1 - Electric Power Systems and Generation (19:41 minutes)
  • Lecture 2 - Large Central Generating Stations (11:35 minutes)
  • Lecture 3 - Other Types of Large Generating Stations (16:23 minutes)
  • Read: Generation
  • Watch: Hydroelectric Innovation
  • Lecture 4 - Overview of DER Technologies (30:28 minutes) Preview
  • Solar Power and the Electric Grid (.pdf)
  • Lecture 5 - Transmission in the US and Transmission Lines (28:52 minutes)
  • Read: Transmission
  • Lecture 6 - Bulk Power Systems and DER (23:21 minutes)
  • Read: FERC Order No. 2222
  • Week 1 Presentation Materials (.pdf)
  • Generation and Transmission Systems
Module 3 - Voltage, Current, and Power Fundamentals

There are some basic electric fundamentals that anyone working with solar and utility systems needs to know. This week covers topics such as voltage, current, and power; impedance; watts, vars, and volt-amps; power factor; single-phase and three-phase circuits; and grounding.

  • Lecture 1 - Basic Definitions and DC Electricity (14:18 minutes) Preview
  • Read: Circuit Basics
  • Read: Basic Electrical and Electronic Concepts
  • Lecture 2 - Alternating Current (AC) (30:10 minutes)
  • Lecture 3 - Power and Power Factor (27:45 minutes)
  • Lecture 4 - Three Phase Power (28:50 minutes)
  • Watch: Generation of Three-Phase Power
  • Homework Problems (.pdf)
  • Homework Solutions (.pdf)
  • Quiz - Voltage Current and Power Fundamentals
  • Week 2 Presentation Materials (.pdf)
  • Supplemental Material on Per Unit System (.pdf)
Module 4 - Distribution Systems

In the next week-and-a-half, we look at the common characteristics of North American style utility distribution systems. This knowledge is intended to give you background on the historic context of distribution systems, and why it can sometimes be challenging to connect large amounts of solar PV to it. This includes basic design and operating concepts, architectures, voltage levels, equipment, and operating principles. We'll look at the impact that distribution characteristics have on the location and quantity of solar on the system, including source impedance; radial, looped, and networked systems; minimum and peak feeder loads; feeder sectionalizing; and system stiffness.

  • Lecture 1 - Overview of Utility Distribution (14:47 minutes)
  • Lecture 2 - Electric Customer Loads (14:42 minutes)
  • Lecture 3 - Subtransmission (13:27 minutes)
  • Lecture 4 - High-Voltage Side of Substations (18:17 minutes)
  • Watch: 500 kV Circuit Breaker and Disconnect Switch Operation
  • Watch: Three Types of Transmission Disconnect Switches
  • Lecture 5 - Distribution Substation Transformers (11:21 minutes)
  • Lecture 6 - Distribution Substation Low-Side Equipment (10:49 minutes)
  • Lecture 7 - Substation Protection, Control and Monitoring Equipment (19:46 minutes)
  • Watch: Medium-voltage Switchgear
  • Lecture 8 - Introduction to Distribution Feeders (25:20 minutes)
  • Distribution Feeder Diagram (.pdf)
  • Common Distribution Measurement Units and Quantities (.pdf)
  • Read: T&D System (.pdf)
  • Typical Electrical Drawing Symbols and Conventions
  • Week 3 Presentation Materials (.pdf)
  • Overhead Conductors, Underground Cables, and Transformers
Module 5 - Distribution Systems and Utility-Scale Solar PV Interconnection

In this week, we'll finish the material on distribution systems and then progress into the first part of Utility-Scale Solar PV Interconnection.

  • Intro Lecture - Week 4 (02:02 minutes)
  • Lecture 1 - Overhead Conductors (22:24 minutes)
  • YouTube: Overhead Line Conductors
  • Lecture 2 - Underground Cables and Three-Phase Transformers (19:14 minutes)
  • Medium-Voltage Transformers
  • Lecture 3 - Feeder Architecture (15:18 minutes)
  • Lecture 4 - Distribution System Grounding (10:31 minutes)
  • Solar PV Overview
  • Watch: Solar PV Electric Power Generation
  • Trends in Solar PV - End of 2021
  • Lecture 5 - Utility-Scale Solar PV Plants and PV Plant Equipment (25:58 minutes)
  • Lecture 6 - Solar PV Plant Equipment (19:12 minutes)
  • Read: DC Combiner Boxes
  • Transformers for Solar Farms I (.pdf)
  • Transformers for Solar Farms II (.pdf)
  • Week 4 Presentation Materials (.pdf)
Module 6 - Utility-Scale Solar PV Interconnection on Distribution

In this module, we start with the basics of solar PV farms on distribution, before we get into more detail in the coming weeks. We start by looking at common solar PV issues on distribution. We also look at topics such as interconnection requirements including equipment and its function, inverters and their functionality with respect to the grid, grounding, SCADA connection and communications, and transformer winding configurations.

  • Intro Lecture - Week 5 (01:47 minutes)
  • Lecture 1 - Solar PV Plant Layouts (18:57 minutes)
  • Read: PV Power Plant AC Collection Systems (.pdf)
  • Lecture 2 - Useful Metrics (09:04 minutes) Preview
  • Read: Inverter Loading Ratio
  • Lecture 3 - High-Penetration Solar PV and Smart Inverter Development (21:07 minutes)
  • Read: Smart Inverter Benefits
  • Lecture 4 - Overview of IEEE 1547-2018 (16:58 minutes)
  • Read: Impacts of DER on T&D System (.pdf)
  • Lecture 5 - IEEE 1547 and Frequency Requirements (12:25 minutes) Preview
  • Lecture 6 - IEEE 1547 and Power Quality (05:09 minutes)
  • Lecture 7 - IEEE 1547 and Interoperability (13:29 minutes)
  • DNP3 Protocol
  • Lecture 8 - IEEE 1547 and Certification/Testing (12:46 minutes)
  • Read: Advanced Inverter Tests (.pdf)
  • Example of Inverter Listing Request Instruction (.pdf)
  • Week 5 Presentation Materials (.pdf)
Module 7 - Distribution Voltage Regulation and Solar PV Generation

Distribution voltage control/regulation, as well as reactive power control, is one of the most important design and operating principles that a utility must consider. With the introduction of IEEE 1547-2018, solar plants are facing new voltage control requirements. During this week, we'll look at voltage requirements that utilities must provide their customers; voltage drop that occurs on distribution feeder primaries and secondaries; utility voltage control equipment; common impacts of solar installations on utility voltage supply; and possible solutions to voltage issues created by solar installations, including smart inverter controls impacting voltage and reactive power. We also discuss voltage flicker and sags, and inverter ride-through capability.

  • Intro Lecture - Week 6 (14:37 minutes)
  • Lecture 1 - Voltage Ranges and Voltage Drop (26:41 minutes)
  • Lecture 2 - Voltage Regulators (18:15 minutes)
  • Watch: Voltage Regulator Controller
  • Read: Feeder Voltage Regulation (.pdf)
  • Lecture 3 - Capacitors, Reactive Power, and Voltage (16:16 minutes)
  • Lecture 4 - Solar PV and Feeder Voltage Profiles (15:06 minutes)
  • Lecture 5 - Solar PV and Voltage Variability (02:57 minutes)
  • Lecture 6 - IEEE 1547 and Voltage Regulation (14:37 minutes)
  • Lecture 7 - Reactive Power Control Modes (18:49 minutes)
  • Read: Voltage Control and DER
  • Read: IEEE 1547-2018 and Solar PV Reactive Power/Voltage Control (.pdf)
  • Lecture 8 - Abnormal Operating Performance and Voltage Ride-Through (09:03 minutes)
  • Voltage Control and Monitoring
  • Week 6 Presentation Materials (.pdf)
Module 8 - Distribution Protection and Solar PV Generation

Short-circuits and overcurrent protection is a key design consideration for utility systems, with considerations on solar plant design and operation. This week we'll look at the nature of distribution system faults, overcurrents, and key design principles including instantaneous and time-delayed tripping, reclosing, and post-fault restoration practices. We'll discuss over/under voltage and frequency events on the system, and how they impact the solar PV plant. We'll also look at the potential for unintentional islanding and ground fault overvoltages, and possible mitigation measures, including 3Vo protection and DTT (Direct Transfer Trip).

  • Intro Lecture - Week 7 (03:24 minutes)
  • Lecture 1 - Distribution System Faults (21:37 minutes)
  • Watch: The Reason Why System Protection is Needed
  • Lecture 2 - Distribution Protection Objectives (20:31 minutes)
  • Lecture 3 - Relayed Circuit Breakers and Fuses (13:15 minutes)
  • Watch: Operation of Explusion Fuse
  • Lecture 4 - Reclosers (12:29 minutes)
  • Watch: Demonstration of Recloser Features
  • Watch (Optional): Reclosers Overview
  • Read: Solar PV Tie Recloser
  • Read: Distribution Protection Overview
  • Lecture 5 - Solar PV and Distribution Protection (09:47 minutes)
  • Lecture 6 - IEEE 1547-2018 and Overvoltages (14:07 minutes)
  • Lecture 7 - IEEE 1547 and Islanding (13:38 minutes) Preview
  • Lecture 8 - Selected Protection Requirements from Utilities (06:25 minutes)
  • Read: Summary of Smart Inverters and IEEE 1547-2018 (.pdf)
  • Week 7 Presentation Materials (.pdf)
  • Quiz - Protection and Solar PV
Module 9 - Hosting Capacity and Interconnection Procedures

Estimating what the impacts of new solar PV farms on distribution systems is important for utility engineers as well as developers. In this section, we look at some Hosting Capacity studies and maps which some public service commission and distribution organizations now use, some additional technical screens, and an overview of distribution interconnection procedures.

  • Lecture 1 - Introduction to Hosting Capacity Analysis (15:05 minutes)
  • Watch: Demonstration of a Utility's Hosting Capacity Map (26:28 minutes)
  • Lecture 2 - Hosting Capacity Criteria and Thresholds (19:52 minutes)
  • Read: IREC Hosting Capacity Analysis White Paper
  • Lecture 3 - Solar PV Screening Ratios (12:32 minutes)
  • FERC SGIP - For Generating Facilities No Larger Than 20 MW (.pdf)
  • Lecture 4 - Interconnection Procedures (28:31 minutes)
  • Summary of the Fast Track and Supplementary Review Process (.pdf)
  • Lecture 5 - The Study Process, Including System Impact Studies (15:52 minutes)
  • Read: Tips for Successful Interconnection of Small Renewables (.pdf)
  • IREC Model Interconnection Agreement (.pdf)
  • Week 8 Presentation Materials (.pdf)
  • Utility-Scale PV Resources (.pdf)


Tim Taylor

Owner and Managing Director, Electric Distribution Academy

Tim is Owner and Managing Director of Electric Distribution Academy and has over 30 years of experience in distribution system engineering. He’s led and participated in many projects with many North American utilities and has also worked in Europe and Latin American. In addition to papers, articles, and conference presentations, he has served as an instructor for... Learn more


3 reviews

13 students have taken this course

by John Selby 09/20/2022

Tim's class is a fantastic intro to the world of distribution connected solar. He provides historical perspective as well as looks into the future for trends that are coming down the road. If you're getting into developing or designing utility scale projects, this course is great!

by SARANYA R 10/05/2022

by Ruihua Y 09/23/2022

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Frequently asked questions

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You can begin this online course instantly upon enrollment. This 9 module course is delivered entirely online. The lecture video and other materials are available any time. After successfully completing the course, you will be able to generate a certificate of completion.

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Students get unlimited access to the course materials as soon as they enroll and for one year (365 days) after enrollment. Rewatch videos and review assignments as many times as you want. View updates the instructor makes to the course as the industry advances. Return to your course anytime with online access from anywhere in the world. After the one year of access expires, access can be extended by joining as a HeatSpring member. A single membership extends access to course materials for all past enrollments.

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