Study and testing on distribution systems (neutral conductor) trainer

Framework is made of sheet steel chemically treated and painted with several coats of epoxy varnish; its base is provided with rubber feet and it can be positioned on a working top. All the necessary electric components for the correct power supply of circuits are included in the panel. Here are the main components installed and accessible, electrically, via safety terminals for plugs with diameter of 4 mm:

• 1 three-phase insulation transformer – 230-400 V / 230-400 V; 1500 VA
• 1 differential circuit breaker – 4 x 6 A; curve C with minimum voltage releasing coil, stop/emergency button with mechanic holding and signalling LED on operation panel
• 1 power line of 230 Vac -1 A for powering auxiliary devices
• 1 three-pole lever selector for inserting two different values of capacitance to earth in IT line
• 1 simulation of substation earthing with resistances of 0.3 Ω, 1 Ω
• 1 simulation of earth plate with resistances of 2 Ω, 20 Ω, 200 Ω, 2 kΩ
• 2 simulators of power consuming devices with sinusoidal or unidirectional earth fault current; fault resistance of 50 kΩ, 15 kΩ, 5 kΩ, 1.5 kΩ, 500 Ω, bolted fault
• 1 monitor for checking the isolation in IT systems with adjustment of the value of tripping sensitivity, and scale for monitoring the instantaneous value of insulation resistance of the installation
• 1 differential circuit breaker 4 x 2 A, curve C, provided with remote opening current start-up coil
• 1 four-pole differential circuit breaker of 25 A / 0.3 A, class A, “S” selective
• 1 set of three fuse holders, with breakable neutral conductor and fuses 10.2 x 38 of 1 A and 2 A
• 1 automatic magnetothermal differential switch 2 x 1 A, curve C, class AC, with possibility of using the only magnetothermal switch without the differential part
• 1 automatic magnetothermal differential switch 2 x 1 A, curve C, class A, with possibility of using the only magnetothermal switch without the differential part
• 1 differential relay coupled to a toroidal transformer with adjustable current Idn and tripping time