Kilovar-hour ( quar · h ) is a non-systemic unit of measurement of a part of electrical energy (reactive energy  ), transmitted due to the reactive component of electrical power ; derivative unit of a non-systemic var (international var  ), where var is an abbreviation for volt-ampere reactive ( volt-ampere reactive ) . Used in the national economy to measure with the help of modern electronic meters   of electrical energy to the characteristics of additional losses in the systems of power supply, which may be significant due to loads with large capacitive or inductive components  .
The reactive power flows between the consumer and the power supplying organization are inexpedient, since they lead to an increase in the required power of electric generators , transformers , the cross-section of the supply cables (due to the reduction in throughput). In general, the reactive component of the current of the power supply network of the consumer leads to an increase in active losses on the equipment of the power supplying organization, and, as a result, to a voltage drop at the consumer. Therefore, significant reactive power must be compensated directly at the consumer, for example, through the installation of passive or active power factor correctors. 
To account for reactive energy using special meters that are able to separately take it into account.
- GOST R 52320-2005 (IEC 62052-11: 2003) Equipment for measuring the electrical energy of alternating current. General requirements. Tests and test conditions. Part 11. Electricity meters
- Dire Voltage – ampere (symbol 'VA') symbol 'var') when it is used to express reactive electric power. " Chapter 1.2.3., P. 6
- Single-phase multifunction energy meter CE208BY. Instruction manual TsLFI.411152.097 RE
- KASKAD-1-MT active and active-reactive electric energy meter multifunction. Description of type KASKAD-1-MT. http://oaokaskad.ru/wp-content/uploads/2015/06/Opisanie-tipa_Kaskad-1-MT.pdf
- for example, asynchronous engines running at speeds close to idle, without appropriate compensation in the frequency tractors
- Various types of power factor correction
- Kilowatt hour
- Amp hour
- Electric energy meter
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