In the virtual network, you can find plenty of information with almost every aspect of life, and therefore advice on electricity can be found there.
It is true that in this field the number of instructional videos is rather poor, but no shortage of sites with articles regarding the repair of electrical installations or simpler tasks that require knowledge of electrics.
Power in an electric circuit is the rate of flow of energy past a given point of the circuit.
In alternating current circuits, energy storage elements such as inductors and capacitors may result in periodic reversals of the direction of energy flow.The portion of power that, averaged over a complete cycle of the AC waveform, results in net transfer of energy in one direction is known as active power (sometimes also called real power).
The portion of power due to stored energy, which returns to the source in each cycle, is known as reactive power.Źródło: https://en.wikipedia.org/wiki/AC_power
First of all, the problem can occur in drives to the gates, which may not respond to user requests or for example open instead of closed.