Perhaps the most recognized industry standard in North America for surge protectors may be UL 1449, the Standard for Safety for Surge Protective Devices ranging in applications from surge arresters (1000v ac max) to service entrance and distribution panels to plug-in surge strips. The standard was officially adopted as an ANSI standard in May 2010 and a supplement specific to the evaluation of Photovoltaic applications is expected in 2011. However, it is important to keep in mind that UL 1449 is first and foremost a safety standard. For more in-depth information regarding characterization of the surge environment, test methods and the application of these devices, the IEEE C62 standards are the definitive source in North America.
The IEEE Surge Protective Devices Committee (SPDC) meetings were held the week of November 8 in Clearwater, FL. The SPDC working groups meet twice every year in the Spring and Fall under the Power & Energy Society of the Institute of Electrical and Electronics Engineers (IEEE). Many engineers around the world use the standards contained in the C62 collection, therefore working groups continually strive for harmonization with complementary IEC standards in their efforts to expand and/or update standards development activities.
Often referred to as “a trilogy” concerning the occurrence, characterization and testing of surges in low-voltage ac power circuits, the following C62 standards published in 2002 provide a solid base of fundamentals on the subject:
C62.41.1 – IEEE Guide on the Surge Environment in Low-Voltage (1000V and Less) AC Power Circuits.
C62.41.2 – IEEE Recommended Practice on Characterization of Surges in Low-Voltage (1000V and Less)
AC Power Circuits.
C62.45 – IEEE Recommended Practice on Surge Testing for Equipment Connected to Low-Voltage (1000V and Less) AC Power Circuits.
The responsible working group, WG 3.6.4 is presently developing a long term plan to keep these documents up to date with the latest developments and research papers in the field. The group is also responsible for C62.48, IEEE Guide on Interactions between Power System Disturbances and Surge Protective Devices.
This past year some exciting, new working groups have formed to keep up with trends specific to the power transmission and distribution industry. These groups are:
WG 3.6.11 – Protection Guide for Wind Generation Systems will develop guidelines for surge protective devices on electrical equipment and systems with voltages of 1000 V(ac) and
1200 V(dc) or less within a wind generation system. Included within this scope are communications and data acquisition equipment and associated circuitry and interfaces.
WG 3.6.12 – Protection for Photovoltaic Facilities will development test specifications and application guidance for surge protective devices on electrical equipment and systems with voltages of 1000 V(ac) and 1200 V(dc) or less within a photovoltaic facility or installation. It will also consider communications and data acquisition equipment and associated circuitry and interfaces.
WG 3.6.13 – Smart Grid Protection Guide will develop guidance for surge protective devices connected to electrical equipment and systems with voltages of 1000 V(ac) and 1200 V(dc) or less for components of the Smart Grid. Included within this scope are communications and data acquisition equipment and associated circuitry and interfaces. Additionally, there are cases, which involve smart grid equipment attaching or coupling to higher voltage circuits such as electric utility medium voltage distribution. This scope is not limited to providing guidance for such matters.
In addition, working group WG 3.6.6 has been quite busy expanding C62.62 (2000) IEEE Standard for Test Specifications for Surge Protective Devices for Low-Voltage AC Power Circuits. Revisions include modifications to previous tests and several new tests such as short-circuit current ratings, nominal discharge current and operating duty cycle, Another important revision is the formatting which now includes rationale, purpose, test procedure and setup, and expected results. It should also be noted that the document now clearly defines its scope for installations on the load side of the service equipment; IEEE C62.34 Standard for Performance of LV SPDs/Secondary Arresters covers line side installations. Publication of the revised C62.62 standard is expected in 2011. This group is also working on expanding the 2007 version of the IEEE Guide for the Application of Surge Protective Devices for Low-Voltage (1000V or Less) AC Power Circuits; a useful guide to assist specification engineers on installation and coordination of SPDs in a facility.
Other activities of interest include WG 3.6.10 with development on draft C62.50, Standard for Performance Criteria and Test Methods for Plug-in, Multiport SPDs which include communication ports and associated ground equalization reference considerations. WG 3.6.7 is responsible for standards development in the communications field including C62.43, Application Guide for SPDs used in Data, Communications and Signaling Circuits.
On the discrete component side, WG 3.6.3 responsible for C62.42, the Guide for the Application of Component SPDs for use in Low-Voltage Circuits serves as a very useful resource to design engineers who employ gas discharge tubes, air gaps, metal-oxide varistors and avalanche diodes in end use products. These are components which correlate to a Type 5 SPD
in UL 1449.
This summary offers just a very brief overview of the breadth of IEEE C62 SPD Standards. Engineers engaged in the surge protection industry are encouraged to participate in respective working groups to contribute in their areas of expertise. The tireless dedication of working group members has resulted in a comprehensive contribution to the field and it is encouraging to see the SPDC continue to update and expand existing standards; as well as create new standards projects to keep pace with emerging trends and technologies. For more information, please visit the SPDC website at http://grouper.ieee.org/groups/spd.
Matthew Wakeham is an independent consultant focused in the fields of power quality, energy management and electrical safety. He has held positions managing new product development groups, as well as a senior project engineer at Underwriters Laboratories. Matt is a member of the IEEE Power & Energy Society and participates on several SPDC working groups including Vice Chair for WG 3.6.13 Smart Grid Protection. He is also a voting member of the UL 1449 Standards Technical Panel for Surge Protective Devices. He has a B.S.E.E. and holds several U.S. patents. Matt can be reached at mwakeham@powernota.com or 212‑877‑9515.
