Editing Electric power transmission (section)

== Control ==
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To ensure safe and predictable operation, system components are controlled with generators, switches, circuit breakers and loads. The voltage, power, frequency, load factor, and reliability capabilities of the transmission system are designed to provide cost effective performance.

=== Load balancing ===
The transmission system provides for base load and [[peaking power plant|peak load capability]], with margins for safety and fault tolerance. Peak load times vary by region largely due to the industry mix. In hot and cold climates home air conditioning and heating loads affect the overall load. They are typically highest in the late afternoon in the hottest part of the year and in mid-mornings and mid-evenings in the coldest part of the year. Power requirements vary by season and time of day. Distribution system designs always take the base load and the peak load into consideration.

The transmission system usually does not have a large buffering capability to match loads with generation. Thus generation has to be kept matched to the load, to prevent overloading generation equipment.

Multiple sources and loads can be connected to the transmission system and they must be controlled to provide orderly transfer of power. In centralized power generation, only local control of generation is necessary. This involves [[alternator synchronization|synchronization of the generation units]].

In [[distributed generation|distributed power generation]] the generators are geographically distributed and the process to bring them online and offline must be carefully controlled. The load control signals can either be sent on separate lines or on the power lines themselves. Voltage and frequency can be used as signaling mechanisms to balance the loads.

In voltage signaling, voltage is varied to increase generation. The power added by any system increases as the line voltage decreases. This arrangement is stable in principle. Voltage-based regulation is complex to use in mesh networks, since the individual components and setpoints would need to be reconfigured every time a new generator is added to the mesh.

In frequency signaling, the generating units match the frequency of the power transmission system. In [[droop speed control]], if the frequency decreases, the power is increased. (The drop in line frequency is an indication that the increased load is causing the generators to slow down.)

[[Wind turbine]]s, [[vehicle-to-grid]], [[Virtual power plant|virtual power plants]], and other locally distributed storage and generation systems can interact with the grid to improve system operation. Internationally{{Where|date=October 2024}}, a slow move from a centralized to decentralized power systems have taken place. The main draw of locally distributed generation systems is that they reduce transmission losses by leading to consumption of electricity closer to where it was produced.<ref>{{cite web | url = https://www.en-powered.com/blog/the-bumpy-road-to-energy-deregulation | title = The Bumpy Road to Energy Deregulation | publisher = EnPowered | date = 2016-03-28 | access-date = April 6, 2017 | archive-date = April 7, 2017 | archive-url = https://web.archive.org/web/20170407145323/https://www.en-powered.com/blog/the-bumpy-road-to-energy-deregulation | url-status = dead }}</ref>

=== Failure protection ===
Under excess load conditions, the system can be designed to fail incrementally rather than all at once. [[Brownout (electricity)|Brownouts]] occur when power supplied drops below the demand. [[Power outage|Blackouts]] occur when the grid fails completely.

[[Rolling blackout]]s (also called load shedding) are intentionally engineered electrical power outages, used to distribute insufficient power to various loads in turn.