Standardization Efforts of International Electrotechnical Commission Related to Surge Protection Components, and Receipt of METI Minister’s Award

1.1 Emergence of new issues

Lightning protection measures up to now have mainly focused on preventing permanent damage or fires caused by burning, scorching, or melting as a result of an insulation breakdown within information and communication technology (ICT) equipment and electric/electronic appliances triggered by overvoltage or overcurrent surges caused by lightning. Today, advances in lightning protection technology have reduced equipment damage due to overvoltage breakdown in hardware, but data errors have recently become evident as a new form of lightning-related damage. This is a phenomenon in which errors occur in data being processed even if the hardware itself has suffered absolutely no damage. It can give rise to problems such as corruption of original data, equipment freezing, system hang-ups, malfunctions, out-of-control operation, and system downtime. In the event of such a problem, it is usually possible to restore operation by resetting the equipment, turning power OFF/ON (rebooting), reloading the operating system, or restoring (salvaging) corrupted data. Nevertheless, such lightning-related data errors run the risk of lost opportunities, disappearance of immediately previous data deliverables, and failure to notice that data errors lay hidden within memory. While data errors that occur during data reading or transfer can usually be handled by error-correcting code, the need has arisen for more robust measures against data errors that occur at the time of a lightning strike.

1.2 Problem with Japan’s isolated earth environment

Surge isolation transformers (SITs) have been widely used in Japan’s power supply system for some time. They are known as lightning-resistance transformers, and they have rarely been used outside Japan. To give some background, while Japan focused on isolated-earth systems, the trend overseas was integrated-earth systems and lightning protection by equipotential methods such as using the earth as a reference point. For example, grounding for communications in Japan has been achieved by installing subscriber arresters for communications use in all telephone subscriber homes, but this method involves the independent grounding of subscriber arresters in isolation from the grounding of power systems, buildings, and other elements. As a result, the following problem arises with Japan’s isolated earth environment: if a lightning surge flows in one such earth connection, an earth potential rise occurs due to earth resistance, resulting in a new overvoltage surge source.

The International Electrotechnical Commission (IEC) has been active in developing standards for surge protective devices (SPDs) and surge protective components (SPCs) used in equipotential methods, and the development of standards for isolation methods has been progressing at the Institute of Electrical and Electronics Engineers (IEEE) and International Telecommunication Union - Telecommunication Standardization Sector (ITU-T).

2.1 IEC/SC 37B organization

IEC Technical Committee (TC) 37 (surge arresters)/ Subcommittee (SC) 37B (components for low-voltage surge protection) is a group working to establish IEC international standards on discrete surge-protection components that reduce lightning surges to a sufficiently small level to protect the human body, equipment, and appliances. Four international standards have been established so far: IEC 61643-311: GDTs (gas discharge tubes); IEC 61643-321: ABDs (avalanche breakdown diodes); IEC 61643-331: MOVs (metal oxide varistors); and IEC 61643-341: TSSs (thyristor surge suppressors) (Fig. 1). All of these standards concern components for achieving overvoltage protection through lightning equipotential methods using the voltage non-linear resistance characteristics of these SPCs. In relation to the above, Japan submitted a new work item proposal (NP) on SITs as a fifth type of SPC using an isolation method completely different from the above equipotential methods.

Fig. 1. Equipotential and isolation lightning-surge protection methods and their international standards.

2.2 Overview of Working Group (WG) 3 project activities

The initial 2010 NP and CD (committee draft) was approved by international vote, but since the participation of at least four overseas experts required for establishing a project could not be obtained from the 14 participating members (P-members), Japan’s proposal for a new IEC project was rejected. We attributed this to the low international awareness of SITs. We therefore conducted an information campaign over the next two years to heighten worldwide awareness, and by resubmitting the NP in 2012, we succeeded in establishing an IEC 61643-351/352 project through the participation of experts from the four countries of China, Germany, the United Kingdom, and Japan. IEC/SC 37B/WG 3 (surge isolation transformers) was then established with the author as convenor, and standardization work began.

At the same time, France and the United States opposed this project for the reason that SITs were outside the scope of SC 37B. They argued that the scope of IEC SC 37B, the parent subcommittee, is components for use as SPDs, and the definition of an SPD was “a device incorporating one or more non-linear elements having the purpose of limiting surge voltage and diverting surge current,” so SITs, having no non-linear elements, were outside the scope.

A revision to the scope of SC 37B was therefore proposed by Japan at the 2013 plenary meeting and discussions, and the result of an international vote produced the following new scope: “To prepare international standards for components for low-voltage surge protection. These SPCs are used in power, telecommunication and/or signaling networks with voltages up to 1000 V a.c. and 1500 V d.c.”

In other words, all components that reduce surge, or SMCs (surge mitigation components), were now to be handled by SC 37B, and on the basis of this revision, France and the United States became involved as experts. Additionally, an IEC NP in relation to SITs proposed by Japan was introduced at the ITU-T SG5 (Study Group 5: environment and circular economy) meeting in Geneva held from April 26 to May 3, 2011. As a result, even ITU-T came to recognize the need for SITs, and thus, SIT-related activities progressed with a liaison member.