This paper describes contributions of IEC 61850 to the green transformation (GX), a new economic growth strategy. IEC 61850 has already been applied to substation automation systems and distribution automation systems in Japan, so the industry is starting to show some real ability to build and operate IEC 61850 based systems. In addition, IEC 61850 extends its scope to a sector coupling between electricity and thermal energy as well as electric vehicle as DER. The expansion will make IEC 61850 a growth engine for various energy industries. Products and services related to IEC 61850 are expected to realize GX in near future.

The larger variable renewable energy (VRE) is introduced, the more adjusting power is required to keep power system frequency. This paper evaluates effects of battery storage system introduction and tie-line capacity enlargement with supply and demand simulation model, considering accurate constraints of adjusting power. Future fluctuations and forecast errors of VRE output are also considered to reflect the required adjusting power, which will increase together with VRE capacity. The simulation model minimizes the annual total costs of power system in 2030 with many hourly constraints in 9 areas in Japan. Results show that battery storage system introduction decreases much of VRE curtailment, whereas tie-line capacity enlargement has limited effects on the curtailment, because battery storage system can supply adjusting power while tie-line power flow can level VRE curtailment across areas. When kWh capacity of battery storage system is constant, the larger ratio of kW/kWh capacity is confirmed to be more effective in reducing VRE curtailment, total cost, and CO₂ emission.

Several types of fault current limiters have been studied so far, including superconductor based one or non-superconductor based one. However, it is difficult to satisfy all requirements for cost, maintainability, and current limiting performance. This study proposes another type of fault current limiter, variable transformer based one. It is supposed to be less expensive and easier to be maintained since it is based on the conventional transformer, and to be expected better current limiting performance since the magnetic circuit of the transformer is drastically changed. The magnetic circuit of the transformer is switched to be opened and to produce another one by shifting a portion of its iron core mechanically, allowing the primary and secondary electric circuit to be magnetically isolated. In that way, the electromotive force of the secondary winding could be reduced so that the secondary current could be limited. The prototype based on this concept was designed and built up, and its stational performance has been investigated. As a result, it was confirmed that the prototype shows good current limiting performances identical to the results of the previous FE analysis. Furthermore, the prototype was connected to the operating mechanism to investigate the transient performances, and as a result satisfying current limiting performances are confirmed.

A separable connector is used for the power cables and apparatuses in renewable energy systems. The shield of the collector cable is sometimes an open circuit at one end to reduce power loss due to the shield current. However, this has a disadvantage from the viewpoint of lightning protection. The semi-conductive part of the separable connector is grounded for safety. The ground potential rise due to a direct lightning strike to a wind tower sometimes damages the collector cables and power apparatuses in the wind tower. Combustion in a cable is one of the most serious types of lightning-caused damage. This paper describes an experimental study on fire ignition in a collector cable caused by a ground potential rise due to a direct lightning strike to a receptor. The mechanism leading to fire ignition is discussed based on the experimental results. This paper also proposes a countermeasure against such fire ignition.

We investigate concurrent flashover characteristics under short-tail lightning impulse voltage by using two parallel gaps in air assuming multi-phase back-flashover for 66/77kV overhead transmission lines. The experiment is conducted by using two types of experimental cases. One is rod-rod/rod-rod electrode parallel configuration, the other is EGLA/rod-rod. Short-tail lightning impulse voltage is applied by using a 12MV impulse generator in Shiobara Testing Yard of CRIEPI assuming that lightning strikes a transmission tower. DC voltage is superimposed on one side of two parallel gaps in consideration of the effect of AC phase difference in the actual transmission lines. As a result, we experimentally clarify that concurrent flashover occurs at the flashover electric field E_FO from 0.83 to 1.22kV/mm in the air gap.