In Kenya, electricity is provided by one company, a government parastatal, Kenya Power and Lighting Company (KPLC). Due to its monopoly in the industry, they have demonstrated laxity in previous power black outs, something that has not augured well with Kenyans.
KPLC is tasked with distribution of electricity in Kenya. Although some of the rural parts of the country are not connected to the electricity grid, Nairobi enjoys electricity services 24/7 unless there is power black outs and rationing.
To enjoy these services you only need to buy electricity tokens that will last as per your consumption rate. These are facilitated by KPLC vendors but there is an option of buying via the mobile money transfer platform, MPESA.
The electricity supply is 220 volts alternating current at 50 heltz, like in Europe (UK standard plugs). You are likely to experience frequent power outages in Kenya, so investing in a standby generator or small UPS maybe a good idea but if you stay in apartments they often offer generator services.
When power is reconnected, a sudden high voltage may be experienced which may lead to damage of sensitive electrical components, that is, audio-visual equipment. Brown-outs, low power periods which involves less electricity can also be dangerous to electrical appliances.

The voltage regulators are available in almost all the better electrical goods stores in one of the Nairobi shopping centers.