A two-stage method for optimal placement of distributed generation units and capacitors in distribution systems

Two‐stage planning of synchronous distributed generations in distribution network considering protection coordination index and optimal operation situation

“…• In most researches such as [6][7][8][9][10], SDG planning (sitting and sizing) in the distribution network has generally been adopted to improve the operation indices such as reducing energy losses and improving the voltage profile. In some studies, it has been used to reduce consumer downtime in the event of N−1 or N−k events.…”

“…As per [3], element (b, b) (a diagonal element) of the matrix is the sum of admittances of the lines that are connected to bus b, while off-diagonal elements such as element (b, k) are the negative value of the sum of admittances of the lines connecting bus b to bus k. This is represented by H f in (7) [11]. The limit on the CTI between relay o in the primary operating mode and OCR l in the backup operating mode for fault f is given in (8). The permissible rage of changes for setting parameters of OCRs including TDS and pickup current (I PC ) are presented in constraints ( 9) and (10), respectively [3].…”

“…This is because the backup relays for OCRs in the P 1 position are located at their left. Therefore, to comply with the CTI constraint, (8), it is necessary that in position P 1 , the OCRs at the near-end of the feeder have a higher operating time than the OCRs at the far-end of the feeder. However, to observe constraint (8), the opposite conditions for the OCRs must appear in position P 2 .…”

“…Ref. [8] finds the optimal size and site of DGs and capacitor banks to improve the operation of the distribution network. To this end, it employs a two‐stage algorithm.…”

“…However, considering this in the first solution (such as [7]) will complicate the problem, and the search space will also increase because the solution presented in [7] should be checked at any time (such as year). Finally, it should be noted that the solution to reduce the search space has been stated in less research such as [8]. The problem of placement and sizing of DGs is of NLP nature, similar to protection coordination problem.…”