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Microgrids

We were doing microgrids before microgrids were cool.   We did not call our school boiler plants or campus district energy systems “microgrids” until the EPACT flooded the electrical power industry with a new cadre of policy makers, regulators and litigators and we were forced into a vocabulary upgrade.

We resume our engagement (and advocacy) for a few concepts which have tracked in the NFPA and IEEE standards development catalogs since the early 1990’s:

  1. Nudge development of the National Electrical Code to recognize that loss of electrical power presents (i.e. reliability, availability) a greater hazard, and more frequent hazard, than wiring fire hazard.
  2. The application of stand-alone AC to DC inverters in the 100 – 1000 watt range to convert DC power from an automobile to households.  A portable vehicle to home 120 VAC outlet strip is effectively a “microgrid” and costs less than $100 not including the extension cords.  
  3. Expansion of the hybrid vehicle fittings with a built-in inverter to provide power to households in the 1000-2000 watt range.  In contemporary parlance this arrangement is now referred to as “vehicle to home” (different than vehicle to grid)
  4. Relaxation of NEC prohibitions against the sharing of residential backup generators and electric storage equipment between two or more separate houses.  This can reduce cost significantly.  Earthing, ground fault, disconnect, overcurrent protection can easily be solved if the vertical incumbents we describe in our ABOUT stop voting against us in the National Electrical Code
  5. Stepping up the backup power systems that maintain the needed power for neighborhood internet access.  Not all students and faculty live on campus.  
  6. Policy makers and regulators should think in terms of setting standards for 10-day, 30-day and 90-day survivability contingencies to limit civil unrest.
  7. Preservation of contingencies with a judicious combination of absorption and electric chillers no matter what the electric rate.  During a major regional contingency power is priceless. 
  8. Promote a “cultural change” among specifiers and university design guideline writers to permit use of aluminum wiring which cost 1/3 less than copper wiring.   Use of aluminum wiring for backup “swing feeders” at medium voltage reduces the cost of an additional contingency by 2/3rds.
  9. Reduce National Electrical Code circuit sizing rules so that distribution transformers within buildings can be reduced, thereby reducing material, heat waste and the reduction of wet-stacking in backup generators which reduces reliability.

National Electrical Definitions

This should be enough for an hour.  We continue the conversation 4 times monthly with the IEEE Education & Healthcare Facilities Committee.  Feel free to join us today with the login credentials at the upper right of our home page.

P2030.12/D1.4, Jun 2022 – IEEE Draft Guide for the Design of Microgrid Protection Systems

A Review on Microgrids’ Challenges & Perspectives

Long-term experience of DC-microgrid operation

P2030.10/D12, Apr 2021 – IEEE Approved Draft Standard for DC Microgrids for Rural and Remote Electricity Access Applications

Hierarchical Network Management of Industrial DC-Microgrids

Interconnected Electric Power Production Sources “Microgrids”

“Landscape with a Farm House and Windmill” (1680) / Jacob Isaaksz van Ruisdael

We have always taken a forward-looking approach to the National Electrical Code (NEC) because there is sufficient supply of NEC instructors and inspectors and not enough subject matter experts driving user-interest ideas into it.  Today we approach the parts of the 2023 NEC that cover wiring safety for microgrid systems; a relatively new term of art that appropriates safety and sustainability concepts that have existed in electrotechnology energy systems for decades.

Turn to Part II of Article 705 Interconnected Electric Power Production Sources:

Free Access 2023 National Electrical Code

You will notice that microgrid wiring safety is a relatively small part of the much larger Article 705 Content.   There were relatively minor changes to the 2017 NEC in Section 705.50  — but a great deal of new content regarding Microgrid Interconnection Devices, load side connections, backfeeding practice and disconnecting means — as can be seen in the transcripts of Code-Making Panel 4 action last cycle:

Code‐Making Panel 4 Public Input Report (692 Pages)

Code-Making Panel 4 Public Comment Report (352 Pages)

Keep in mind that the NEC says nothing (or nearly very little, in its purpose stated in Section 90.2) about microgrid economics or the life cycle cost of any other electrical installation.  It is the claim about economic advantages of microgrids that drive education facility asset management and energy conservation units to conceive, finance, install, operate and — most of all — tell the world about them.

In previous posts we have done our level best to reduce the expectations of business and finance leaders of dramatic net energy savings with microgrids — especially on campuses with district energy systems.  Microgrids do, however, provide a power security advantage during major regional contingencies — but that advantage involves a different set of numbers.

Note also that there is no user-interest from the education facility industry — the largest non-residential building construction market in the the United States — on Panel 4.   This is not the fault of the NFPA, as we explain in our ABOUT.

The 2023 NEC was released late last year.

 

The 2026 revision cycle is in full swing with public comment on the First Draft receivable until August 24, 2024.  Let’s start formulating our ideas using the 2023 CMP-4 transcripts.   The link below contains a record of work on the 2023 NEC:

2026 National Electrical Code Workspace

We collaborate with the IEEE Education & Healthcare Facility Committee which meets online 4 times per month in European and American time zones.  Since a great deal of the technical basis for the NEC originates with the IEEE we will also collaborate with other IEEE professional societies.

Mike Anthony’s father-in-law and son maintaining the electrical interactive system installed in the windmill that provides electricity to drive a pump that keeps the canal water at an appropriate level on the family farm near Leeuwarden, The Netherlands.

Issue: [19-151]

Category: Electrical, Energy

Colleagues: Mike Anthony, Jim Harvey, Kane Howard, Jose Meijer

Archive / Microgrids


 

Designing, Installing, Operating, and Maintaining Microgrids

Leyden Jar electric energy storage; and early form of a microgrid. CLICK ON IMAGE for more information

 

The National Electrical Contractors Association develops a suite of consensus standards titled National Electrical Installation Standards (NEIS) that meet the intent of the National Electrical Code (NEC); particularly where the NEC asserts that an installation be constructed in a “neat and workmanlike manner”.   The scope of the original undertaking, begun in the early 1990’s with University of Michigan as an early adopter, has since expanded into operation and maintenance standards; and more recently into design, installation, operating and maintaining integrated systems such as microgrids*.

Some electrotechnology professionals struggle with the notion of a “microgrid” — a trendy term of art for an integrated system of interactive and distributed power sources that many large research universities have had for decades in their district energy plant.  There are some noteworthy operational differences, however; as a trend toward local power storage accelerates and education facility leaders are under pressure to prove the they have a Smart Grid (even if they already have one).   None of the #SmartCampus conceptions for expansion of microgrids into individual buildings, or regions on campuses, will ever pay for themselves we cannot operate and maintain many of them economically (when set against the operational economics of the electrical supply delivered by the university district energy plant).  The university-affiliated medical research and healthcare delivery campus may be a proof-point, however.

The NECA documents are used by construction owners, specifiers, contractors and electricians to clearly illustrate the performance and workmanship standards essential for different types of electrical construction.  Because the NEC is intended to be primarily a wiring safety standard, the NEIS suite is referenced throughout the National Electrical Code.  Electrical shop foremen and front line electricians take note.

Recommended Practice for Designing, Installing, Operating, and Maintaining Microgrids (Redline)

You may obtain an electronic copy from neis@necanet.org.  Send comments to Aga Golriz, (301) 215-4549, Aga.golriz@necanet.org with a copy of your comments psa@ansi.org.   Because the proposed change is relatively minor editorial/grammatical change, we will not comment on it but encourage other user-interests in the education facilities industry (electric shops, engineering managers, etc.) to at least become familiar with the NECA suite of standards and to incorporate them by reference into their standard practice guides for electrical trades.

NECA Standards and Publication Development Home Page

Our door is open every day at 11 AM for consultation on this and other standards.   Use the login credentials at the upper right of our home page.  Additionally, we will refer this to the IEEE Education & Healthcare Committee, which is a subcommittee in the IEEE Industrial Applications Society which follows — and leads — the development of the emergent #SmartCampus.  That committee meets online 4 times monthly in European and American time zones.  See the IEEE E&H Calendar for date, time and login credentials.

Click on image

 

Issue:

Category: Electrical, Energy

Colleagues: Mike Anthony, Jim Harvey,  Van Wagner

ARCHIVE / NECA 417 Microgrids


LEARN MORE:

NEIS Open Review: Fourth Ballot

NECA SMART GRID: INSTALLATION AND CONSTRUCTION MANAGEMENT ASPECTS FOR ELECTRICAL CONTRACTORS

US DOE: Smart Grid Demonstration Program

NIST and the Smart Grid

IEEE: Utility and Other Energy Company Business Case Issues Related to Microgrids and Distributed Generation

IEEE Standards Association: Microgrids: Back to the Future

Standards Michigan Smart Campus Bibliography (A collection of case studies for the education and healthcare industry)

*Most seasoned electrical power professionals recognize that many large research universities with district energy systems that generate in parallel with a public utility have, for decades, operated with all the essential characteristics of a microgrid (save for the political “buzz”).   On-site power storage for telecommunication and mission critical facilities have been in place for decades; so has back up on-site generation.  Scaling these known sources to provide normal power to a single building, or groups of buildings, is an essential difference, however.   Electrical engineering expertise and judgement is needed to determine the optimal balance between a smart distributed resource (such as a microgrid) and a central resource from an existing district energy system.   An array of microgrids on a large research university campus will have a cost associated with of installing, operating and maintaining them.   

 

 

Wires

Ampere current flows through copper or aluminum conductor due to the movement of free electrons in response to an applied electric field of varying voltages.   Each copper or aluminum contributes one free electron to the electron sea, creating a vast reservoir of mobile charge carriers. When a potential difference (voltage) is applied across the ends of the conductor, an electric field is established within the conductor. This field exerts a force on the free electrons, causing them to move in the direction of the electric field.  The resulting current flow can be transformed into different forms depending on the nature of the device.

Heating: When current flows through a resistor, it encounters resistance, which causes the resistor to heat up. This is the principle behind electric heaters, toasters, and incandescent light bulbs.

Mechanical Work: Current flowing through an electric motor creates a magnetic field, which interacts with the magnetic field of the motor’s permanent magnets or electromagnets. This interaction generates a mechanical force, causing the motor to rotate. Thus, electrical energy is converted into mechanical energy; including sound.

Light: In an incandescent light bulb, a filament heats up ( a quantum phenomena) due to the current passing through it. This is an example of electrical energy being converted into light energy; including the chemical energy through light emitting diodes

Today we dwell on how conductors are specified and installed in building premise wiring systems primarily; with some attention to paths designed to carry current flowing through unwanted paths (ground faults, phase imbalance, etc).   In the time we have we will review the present state of the best practice literature developed by the organizations listed below:

International Electrotechnical Commission

60304 Low voltage installations: Protection against electric shock

Institute of Electrical and Electronic Engineers

National Electrical Safety Code

Insulated Cable Engineers Association

International Association of Electrical Inspectors

National Fire Protection Association

National Electrical Code

Code Making Panel 6

Transcript of CMP-6 Proposals for 2026 NEC

Other organizations such as the National Electrical Manufacturers Association, ASTM International, Underwriter Laboratories, also set product and installation standards.  Data center wiring; fiber-optic and low-voltage control wiring is covered in other colloquia (e.g. Infotech and Security) and coordinated with the IEEE Education & Healthcare Facilities Committee.

Use the login credentials at the upper right of our home page.


Related:

2017 National Electrical Code § 110.5

Neher-McGrath Calculation: Cable Calculation ampacity and Thermal Analysis

ETAP: Cabling Sizing – Cable Thermal Analysis

 

System Aspects of Electrical Energy

Impedance Grounding for Electric Grid Surviability

Electric Power Availability: Cold Weather Preparedness

Architecture of power systems: Special cases

Outdoor Deicing & Snow Melting

Campus Outdoor Lighting

High Voltage Electric Service

Campus Bulk Electrical Distribution

Outdoor Deicing & Snow Melting

“Snow at Argenteuil” | Claude Monet (1875)

Today our focus turns to outdoor electric deicing and snow melting wiring systems identified as suitable for the environment and installed in accordance with the manufacturer’s instructions.  They work silently to keep snow load from caving in roofs and icicles falling from gutters onto pedestrian pathways.

While the voltage and ampere requirement of the product itself is a known characteristic, the characteristic 0f the wiring pathway — voltage, ampere, grounding, short circuit, disconnect and control — is relatively more complicated and worthy of our attention.   Articles 426-427 of the National Electrical Code is the relevant part of the NEC

Free Access 2023 National Electrical Code

Insight into the ideas running through technical committee deliberations is provided by a review of Panel 17 transcripts:

2023 NEC Panel 17 Public Input Report (633 pages)

2023 NEC Panel 17 Public Comment Report (190 pages)

We hold Articles 427 in the middle of our priority ranking for the 2023 NEC.   We find that the more difficult issues for this technology is the determination of which trade specifies these systems — architectural, electrical, or mechanical; covered in previous posts.   Instead, most of our time will be spent getting IEEE consensus products in step with it, specifically ANSI/IEEE 515 and IEEE 844/CSA 293.

Comments on the First Draft of the 2026 NEC will be received until August 28th.

454c656374726f746563686e6f6c6f6779

We collaborate with the IEEE Education & Healthcare Facility Committee which meets online 4 times per month in European and American time zones.  Since a great deal of the technical basis for the NEC originates with the IEEE we will also collaborate with IEEE Standards Coordinating Committee 18 whose members are charged by the IEEE Standards Association to coordinate NFPA and IEEE consensus products.

Issue: [19-151]

Category: Electrical, Energy

Colleagues: Mike Anthony, Jim Harvey, Kane Howard, Jose Meijer


LEARN MORE:

IEEE Standard for the Testing, Design, Installation, and Maintenance of Electrical Resistance Heat Tracing for Commercial Applications

844.2/CSA C293.2-2017 – IEEE/CSA Standard for Skin Effect Trace Heating of Pipelines, Vessels, Equipment, and Structures–Application Guide for Design, Installation, Testing, Commissioning, and Maintenance

 

Kahn Health Care Pavilion

Our tenure in the 2026 National Electrical Code will result in at least a 10 percent reduction in the cost of building premise wiring — (mostly in the feeder power chain) — in healthcare facilities; based on the results of last month’s meeting of Code Making Panel 15.

Assuming electrical power infrastructure is 15 percent of in a $920 million facility like this (excluding interior moveable fixtures), that would have meant an approximate $14 million reduction in cost.  That cost savings cannot be realized because it was designed to an earlier version of the National Electrical Code.

Facilities and Operations

National Electrical Code CMP-15

Healthcare Facilities Code

Hospital Plug Load


Related:

New University of Michigan hospital to be named after philanthropists D. Dan and Betty Kahn

ORT America

$920M Michigan Medicine tower tops out, targets 2025 opening

 

Joint Use of Electric Power Transmission & Distribution Facilities and Equipment

Telephone, telegraph, and power lines over the streets of New York City 1888

 

Guide for the Joint Use of Electric Power Transmission & Distribution Facilities and Equipment

 

Abstract: This guide identifies the mechanisms and an analytic approach for developing consistent rules, agreements, and/or methodologies for the evaluation and inter-entity cooperation managing pole attachments on utility infrastructure that can contain both electric supply as well as communications wireline and wireless facilities.

The common safety codes and accepted good industry practices for joint use are referenced, including items such as clearances and strength/loading requirements, appropriate work rules during installation, maintenance and restoration, and general guidelines. The considerations within this guide can be used to help perform a detailed assessment of attachment installations where communications antennas and related wireline and wireless equipment are to be co-located on joint use structures.

Scope: This guide provides recommendations for the development of consistent guides, agreements, and/or methodologies for the evaluation and inter-company cooperation on managing pole attachments on Electric Utility infrastructure.

Purpose: The Joint Use Guide documents consistent approaches, methodologies and rules for the sharing and co-location of equipment with electric Transmission & Distribution (T&D) facilities for communications such as antennae and/or cable. With the emergence of new communications networks and emerging technologies which depend on widely distributed communications {e.g. 5G and Internet of Things ( IoT)}, the needs of vertical real-estate for use in communications is expected to dramatically increase in the coming years. While electric T&D facilities provide an excellent platform to help meet these needs, there are significant safety and reliability issues associated with their use.
Related:

2023 National Electrical Safety Code

2026 National Electrical Code Workspace

Shrove Tuesday

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