ELECTRICAL APPARATUS AND INSTRUMENTS FOR HIGH-VOLTAGE CURRENT TECHNOLOGY, NAMELY, ELECTRIC TRANSFORMERS, ELECTRIC CONVERTERS, ELECTRIC STORAGE BATTERIES, VOLTAGE REGULATORS FOR ELECTRIC POWER AND ELECTRICAL CONTROLLERS, ELECTRICAL TRANSFORMERS COMPOSED OF ON-LOAD TAP-CHANGERS, OFF-CIRCUIT TAP-CHANGERS AND MOTOR DRIVES FOR ADJUSTING THE OPERATING POSITION OF ON-LOAD TAP-CHANGERS AND OFF-CIRCUIT TAP CHANGERS; ELECTRICAL APPARATUS AND INSTRUMENTS FOR CONTROLLING ELECTRIC CURRENT, NAMELY, ELECTRI...