Standards Development

Scope

This new work proposal (SRD) aims to provide guidelines for the safe operation and maintenance of brasselectrodes in low voltage direct current (LVDC) systems. The proposal will specifically focus on arc flash hazards and the measures that can be taken to mitigate these hazards.

The purpose of this proposal is to develop guidelines that will help operators of LVDC systems to identify and mitigate the risks of arc flash hazards. The guidelines will cover the following topics:

• Identification of arc flash hazards between brass electrodes in LVDC systems

• Procedures for assessing the risk of arc flash hazards between brass electrodes in LVDC systems

• Recommended protective measures and engineering controls using brass electrodes in LVDC systems

The proposal will also consider the need for additional research and development in this area, including the development of new technologies and best practices to further reduce the risk of arc flash hazards in LVDC systems.

Purpose

Series arc is a type of electrical arc discharge that occurs when electrical current discharges through air or gas between two or more conductors, resulting in the formation of arc discharge that can cause significant damage to nearby equipment and pose a risk to personnel. Series arc characteristics between brass electrodes in an LVDC system are affected by several factors, including the voltage, current, and shape of the electrodes, as well as the environmental condition.

The series arc characteristics can be described in terms of its duration, energy, and temperature. The duration of the series arc is determined by the resistance of the connection and the rate at which the surrounding medium absorbs the energy. The energy released by the series arc can be significant, and can cause damage to nearby equipment and pose a risk to personnel.

The temperature of the series arc can also be high, and can result in thermal damage to nearby equipment and cause a fire hazard. The temperature of the series arc is affected by several factors, including the arc current, the arc duration, and the properties of the surrounding medium.

To ensure safe and reliable operation of LVDC systems, it is important to follow relevant safety standards and regulations, conduct thorough risk assessments and hazard analyses, and implement appropriate safety measures, such as proper insulation and clearance distances, use of protective equipment, and regular maintenance and testing. It is also important to consider the specific series arc characteristics of the system and take steps to mitigate the risk of series arc occurrences, such as by using high-quality and reliable materials and equipment, implementing fault detection and protection systems, and limiting the maximum voltage and current levels in the system.

Brass electrodes are commonly used in LVDC systems as they are cost-effective, durable, and have good electrical conductivity. However, these components also come with unique safety challenges, particularly when it comes to arc flash hazards. An arc flash is an electric arc that occurs when electrical current discharges through air or gas between two or more conductors. These arcs can release tremendous amounts of energy, leading to severe burns, injuries, and even fatalities. Therefore, it is essential to develop guidelines for the safe operation and maintenance of brass-electrodes in LVDC systems, specifically focusing on arc flash hazards.

Approximately one billion people worldwide live in areas without access to electricity for the moment. These areas are often sparsely populated so that connecting to the power grid is economically unfeasible or are too far away from the main power plants for traditional central power transmission technology. In some cases, the lack of electricity is due to a lack of infrastructure or a weak economy that cannot support to build power plants. To provide electricity to people living in these areas, renewable energy sources such as solar and wind power, which have ubiquitous availability, have become the most feasible options.

However, renewable energy sources, by nature, produce direct current (DC) power that fluctuates significantly depending on weather conditions, and hence, energy storage systems are also essential for stable and reliable power supply. Currently, the most widely used energy storage device is secondary batteries based on electrochemical reactions, which also operate in DC. Therefore, low-voltage direct current (LVDC) systems are considered a suitable choice for supplying power to electricity access areas.

ESMAP (Energy Sector Management Assistance Program) and the World Bank jointly declared a multi-tier framework for electricity access areas according to the amount of load power level. Among the five tiers, Tier 2 and Tier 3 levels of the electricity supply system are the most effective and urgent for electricity access areas. In 2022, the IEC LVDC Systems Committee published IEC 63318, which provides equipment standards for SELV (Safety Extra Low Voltage) power supply voltage of under 120V and load power of under 800W, for Tier 2 and Tier 3 level residential houses. In this market, inexpensive and safe electrical equipment is required with the proper technology that demands equipment costs of less than 5% of the annual income of local households for annual electricity consumption of 365 kWh.

In particular, residential electrical installations require lighting switches and socket-outlets, which are essential electrical components. In order to address problems caused by direct current arc fault in these installations, protective measures must be established to ensure safety from the arc faults.

The document provides the safe supply voltage and load power areas in which non-expert general users can safely use contact-type switches and/or socket-outlets that adopts traditional copper/brass contacts, especially in ELVDC systems.