Page 232 - Handbook of Electrical Engineering
P. 232

216    HANDBOOK OF ELECTRICAL ENGINEERING

              iii) Hence the voltage across the capacitance is,


                                       V c = V s − V sc
                                         = 19456.7 + j0.0 − 508.35 − j336.28
                                         = 18948.35 − j336.28 volts/phase

              The charging current I c for the capacitance is,

                                                     18949.35 − j336.28
                                               V c
                                          I c =   =
                                               X c       −j530.52
                                             = 0.634 + j35.716 amps
              Deduct I c from I s to find I r ,

                                  I r = I s − I c = 317.92 − j80.691 − 0.634 − j35.716

                                    = 317.286 − j116.41 amps

              The volt-drop in the right-hand side of the cable is V cr ,
                                       R     X 1

                              V cr = I r  + j    = (317.286 − j116.41)(1.25 + j1.375)
                                       2     2
                                 = 556.671 + j290.756 volts/phase

              iv) Hence the voltage received at the load is,


                                    V r = V c − V cr
                                       = 18948.35 − j336.28 − 556.671 − j290.756
                                       = 18391.68 − j627.04 volts/phase
                                   |V r |= 18402.36 volts/phase

              The total actual volt-drop

                                            |V s |− |V r |
                                       V =           × 100
                                               |V s |
                                            (19456.7 − 18402.36)100
                                         =                        = 5.419%
                                                   19456.7
              The receiving end volt-drop with respect to the nominal system voltage is  V n ,

                                            |V n |− |V r |
                                      V n =           × 100
                                               |V n |
                                            (19052.6 − 18402.36)
                                          =                    100 = 3.413%
                                                  19052.6
   227   228   229   230   231   232   233   234   235   236   237