Course Design: Low Voltage Package Design

CONTENT OF THE EXCHANGE RATE PROJECT The exchange rate project is structurally divided into three parts, within which it is necessary to perform: Part 1. Preliminary calculations: 1.1 Calculate transformer parameters, 1.2. Calculate currents in lines 1 to 8 (in some versions to 5), 1.3. Select cable types and sections, 1.4. Calculate cable resistance, 1.5. Calculate voltage drops in the lines and evaluate the admissibility of the obtained values, 1.6. Calculate currents of three-phase short circuits at points 0, 1, 2, 1.6. Calculate single-phase short circuit currents at points 1, 2, 3, 4. Part 2. Selection of electrical control and protection devices: 2.1. Formulate criteria for selection of devices used in power supply diagram, 2.2. According to industrial catalogs, select the following devices: - single-phase load circuit protection devices AB (QF2-QF4), UZO, AVDT (FD2-FD6), - circuit breaker in QF1 engine control and protection circuit, - contactor KM1 and thermal relay KK1 in engine control and protection circuit, - control circuit protection apparatus (FU1 fuse), - buttons to control circuit (SB1, SB2), - load switch at input to NPU QS1, - power circuit breakers QF10, QF11, - enclosure of low-voltage package (I&C), - terminal connections for connection of input and output cables, 2.3. Check all selected devices, 2.4. Build a selectivity map, on which to apply time-current characteristics for devices QF10, QF11, QF1, KK1, calculated short-circuit currents, starting characteristic of the electric motor. Part 3. Design study of the project: 3.1. Draw an electrical schematic diagram of I&C taking into account the selected devices, 3.2. Perform a general drawing of the NPU - place the selected devices in the NPU shell taking into account their overall and installation dimensions - perform electrical connections of the power circuits of the devices and control circuits - mark the wires and devices according to the electrical diagram.