Short answers, pulled from the story.
Electric power distribution is the final stage in the delivery of electricity, yet it remains the most critical link between massive industrial generation and the simple act of flipping a light switch. This system transforms high-voltage energy from transmission lines into usable power for individual consumers, a process that begins at a distribution substation.
Transformers step down transmission voltages, which can range from 44 kV to 765 kV, down to primary distribution voltages typically between 4 kV and 35 kV. In the United States, 7.2, 12.47, 25, and 34.5 kV distribution is common, while 11 kV and 33 kV are common in the UK, Australia and New Zealand.
Rural electrification systems tend to use higher distribution voltages because of the longer distances covered by distribution lines. In rural areas a pole-mount transformer may serve only one customer, and in New Zealand, Australia, Saskatchewan, Canada, and South Africa, Single-wire earth return systems are used to electrify remote rural areas.
In the electricity sector in Japan, the standard voltage is 100 V, with both 50 and 60 Hz AC frequencies being used. Parts of the country use 50 Hz, while other parts use 60 Hz, a relic from the 1890s when local providers in Tokyo imported 50 Hz German equipment and the local power providers in Osaka brought in 60 Hz generators from the United States.
Today's distribution systems are heavily integrated with renewable energy generations at the distribution level of the power systems by the means of distributed generation resources, such as solar energy and wind energy. Such tools include battery storage power station, data analytics, optimization tools, and artificial intelligence based methods like microgenetic, branch exchange, particle swarm optimization and non-dominated sorting genetic algorithm.