Аннотация
It is presented that one of the urgent problems of modern power engineering is the construction of current protections of electrical installations that do not use current transformers with ferromagnetic cores. It is shown that magnetically controlled elements-hercone and inductance coil can be used to build such protections, installing them near current-carrying busbars of electric installation, as they have important advantages for relay protection in comparison with other magnetically controlled elements: they do not require amplifiers for signal transmission, signal transmission is performed by control circuits, not by measuring ones, they do not need temperature influence compensation devices, can simultaneously perform the functions of an analog-digital converter, a measuring transducer and a measuring protection device. New schemes of current protections of electrical installations on reed switches and inductance coils, including with fault control, connected to cells of complete switchgear (switchgear), with the effect of resource-saving materials. Their properties and principle of operation are considered. For the considered current protections, new schemes of their implementation are presented, which confirms the possibility of building current protections for various electrical installations connected to the cells of complete switchgears, with the installation of reed and inductance coils inside them.