Power Distribution and Control Equipment have greatly evolved as the elements of indispensable electrical equipment that drives industry. Fuji Electric has made various efforts with market trends in mind. It has globalized by complying with major foreign standards and strengthened its support for energy and environmental fields through the development of high-voltage direct current equipment.For the substation facilities that support advanced informationization, Fuji Electric has increased the stability and reliability of power supplies while also reducing lifecycle costs by simplifying maintenance inspections. It has also miniaturized and increased the performance of switches and low-voltage circuit breakers, products intended for developing countries such as China and Asia, and power monitoring equipment.

Demands for miniaturization and energy efficiency are increasing for production facilities and machines. The SK series of mini contactors, the world’s smallest size contactors, were designed to meet these demands.
The reduction in external dimensions increases the scope of installation locations, while the addition of strong insulation properties means that these contactors can be used for high voltage applications. We devised isolation mechanism and heat-resistant insulating materials for the contact structure and pursued minimum spring load characteristics and efficiency in electromagnet structure. Fuji Electric also complies with global standards and provides a full lineup of optional products to meet the various demands of its customers.

Efforts to better use resources and energy continue to progress, and there are demands to reduce the size and improve the energy efficiency of the control panels and machinery used in production facilities and other industries. There is also an increased demand to reduce the size and power consumption of the thermal relays in these devices.Fuji Electric applied its store of technology to the development of the TK12 series of thermal relays; it reduced part quantity, implemented thermoplasticity material for the housing, and improved the design of the heating section in pursuit of miniaturization. To meet global demands for safety and operability, the relays have terminal covers that conform to IEC 60529 as standard.

In order to meet diversifying market needs, Fuji Electric is developing 32 to 63 AF compact low-voltage circuit breakers as the new line-up of the G-TWIN global series. The installation area was reduced to 72% of that of previous products, which can help reduce the size of panels and machines. In addition, breaking performance has been increased 1.5 times to provide industry-best compactness and breaking performance. Features include the adoption of a new type of link mechanism and a thermal-electromagnetic over-current release mechanism as miniaturized technology and the adoption of a unique one-contact arc commutation interruption method as advanced breaking technology. These highly extensible breakers are also designed to improve user interfaces through the expansion of the accessory line-up.

Power equipment in data centers requires power supplies with increased reliability and decreased noise, as well as easier exchangeability and maintenance.To develop highly reliable power supplies, Fuji Electric employs the BM3 series having high current-limiting performance and uses selective trip coordination. To improve operation productivity, it developed low-voltage circuit breakers that attach to a busbar using a plugin, along with low-voltage circuit breakers with n-phase protection against harmonic current.We verified problems occurred in electrical installation work for data centers and their technical solutions by using the examples of equipment where these low-voltage breakers are used.

Labor saving for maintenance inspections of vacuum circuit breakers (VCBs) is requested because ensuring of the power stoppage time and workers for maintenance inspections have become difficult and reducing lifecycle costs is needed. Moreover, there are increasing demands for predictive maintenance by observing the switching characteristics of VCBs to determine maintenance inspections. Fuji Electric has developed VCBs for dry air insulated switchgear. The latch mechanism to hold the switch state has been replaced with the magnetic power of the permanent magnet inside the electromagnet for switching and the plunger of the electromagnet and the vacuum valve have been connected to simplify the structure of the VCBs. These VCBs have only a few check items and can detect switching operation errors through the measurement of coil current and voltage.

Recently, protective relays are demanded for applying to system coordination of the power system including distributed power sources such as solar power generation along with improving reliability of power systems and reducing daily inspection workloads. Fuji Electric has developed“ QHA series” digital protective relays for high voltage distribution facilities with enhanced protection features and expanded operation stabilization values that improve reliability. In addition to above, for grid-interconnection applications for distributed generating plants, such as solar power generation and commercial power sources, Fuji Electric has off ered the series two grid-interconnection protective relays that allow detailed configuration of operation values and operation-time set values.

Fuji Electric provides various products to reduce energy consumption and improve power source reliability in power distribution systems. It offers several products that promote reduced energy consumption. One is the “F-MPC04E”, a compact electrical power meter that efficiently monitors terminal equipment, such as distribution boards. Another is the “F-MPC I/O unit”, a digital input and output unit which measures electrical pulses, monitors non-electric energy levels, and outputs warnings. One more is the “F-MPC Igr”, an Igr insulationmonitoring device that constantly monitors for leakage of electricity from critical intelligent equipment. Combined with the existing“ F-MPC”series instruments and packaged software, it makes it possible to monitor electrical power and insulation simultaneously.

Demands are increasing for miniaturization, higher voltage direct current equipment that handles clean energy power sources. Interrupting and switching direct current requires a larger contact gap when equipment is miniaturized so that instantaneous rises of arc voltage over power-supply voltage can be stabilized and insulation quality can be ensured.　To solve this challenge, Fuji Electric used a product and manufacturing perspective to pull together the transitions and trends of basic technology common to various types of equipment and unique inherent technology for the core technology of Power Distribution and Control Equipment, which until now has stored alternating current. By pioneering a contact-device technology fi eld that is not constrained by methods for the interruption and switching of electric currentin the air, Fuji Electric aims for brand of AC/DC interacting equipment with high reliability.

DC power distribution systems are rapidly expanding due to increased use of photovoltaic power generation and other renewable energy, and the spread of storage batteries systems. Fuji Electric is working to develop network protection technology to maintain the safety of DC power distribution systems and has started to off er DC circuit breakers for increasingly high voltage use and other market demands. Fuji Electric investigated the principles of an interruption method that uses the interaction of arc and electrical circuits, and arc control technology essential for interrupting direct current. To detect earth leakage of direct current, Fuji Electric developed elemental technology for a fl uxgate method for advanced direct-current detection, and verified its effectiveness.

Applications for direct current distribution have been increasing with the spread of data centers and renewable energy applications such as photovoltaic power generation. Fuji Electric has been expanding the application scope of its breakers intended for DC circuits in order to meet market demands. This time, it developed breakers for high-voltage direct current (DC 750 V, DC 1000 V) used in the power conditioners of photovoltaic power facilities. By verifying the arc voltage using interruption simulators and interruption testing, and verifying the arc drive through magnetic field analysis and interruption testing, Fuji Electric optimized the structure of the arc-extinguishing chamber and achieved a better level of interruption stability at high voltage than previous products.

Year by year, requirements regarding material are becoming stricter due to strengthened environmental regulations such as the RoHS directive, REACH regulation, and POPs treaty, and environmental issues such as global warming. Fuji Electric replaced the thermosetting resin material in parts with thermoplastic resin material, and it now uses lead-free grease. It is also working to develop halogen-free, flameretardantresin material, and has confirmed the possibility of the realization by using a phosphorus-based flame retardant and plans to switch to it. For its metal materials, it promotes the use of cadmium-free contact points, implementing them after reaching its goals for deposition and temperature increases. It also developed a replacement plating liquid that is PFOS-free and is already using it.

Simulation technology for Power Distribution and Control Equipment includes structural strength analysis to investigate elements such as case strength and the miniaturization of structural parts, and mechanical analysis to improve efficiency of contact point switching and handle operation. Fuji Electric performs thermal analysis on parts such as the case and circuit board to find heat problems that directly affect the miniaturization of products, and the results are used to optimize the part layout. Other analyses are performed, including electromagnetic field analysis, resin flow analysis, and thermal conduction and electromagnetic field interaction analysis. It is currently possible to determine whether a design satisfies functionality and specifications using simulations at the concept design stage.

Fuji Electric develops a great variety of new products to meet the needs of its users. Timely supply of these products is depending on production technology, and we are making efforts to strengthen the production system which enable to respond to changes in the economic environment in recent years. At production centers in Japan, we are cutting stock in half, reforming our supply chain and researching efficient automated production lines. At production centers overseas, we are efficiently procuring parts and materials locally to shorten production lead times, implementing simplified automation to insure quality, and introducing testing equipment. On top of this, Fuji Electric is developing personnel that continually pass down production technology and skills to the next generation, so that it can build a production system that constantly supplies worry-free products.