| 摘要 |
In the field of differential protection schemes there is provided a method of determining a communication time delay (T P 1, T P 2, T P 3, T P 4, T P 5) in a communication network between a local terminal (L) and one or more remote terminals (R; R 1 , R 2 , R 3 , R 4 , R5) within an electrical power network (10; 20; 30) comprises the steps of:
(a) selecting, in respect of the or each remote terminal (R; R 1 , R 2 , R 3 , R 4 , R5) a calculation node (J; J1; J2, J3, J4) in the electrical power network (10; 20; 30);
(b) calculating respective node currents flowing into the corresponding calculation node (J; J1; J2, J3, J4) from the local terminal (L) and the or each remote terminal (R; R 1 , R 2 , R 3 , R 4 , R5);
(c) equating, in respect of the or each remote terminal (R; R 1 , R 2 , R 3 , R 4 , R5), a sum of node currents flowing into the corresponding calculation node (J; J1; J2, J3, J4) to zero according to Kirchhoff's first law; and
(d) extracting, in respect of the or each remote terminal (R; R 1 , R 2 , R 3 , R 4 , R5), a communication time delay (T P 1, T P 2, T P 3, T P 4, T P 5) between the local terminal (L) and the said respective remote terminal (R; R 1 , R 2 , R 3 , R 4 , R5) from a corresponding equated sum of node currents. |
