Self-Adaptive Relaying Scheme of Reclosers for Fuse Saving in Distribution Networks with DG

Abstract

Abstract. With growing penetration of distributed generation (DG) in electrical distribution networks (EDNs), miscoordination between fuse and recloser is more likely. This is the result of change of direction, as well as the magnitude of the fault current in the presence of DG where fuse saving cannot be achievd with standard recloser characteristics. This paper proposes a self-adaptive relaying scheme of reclosing operation for fuse saving in EDNs with DG. The recloser is programmed with a new non-standard characteristic using only the local voltage and current magnitude measurements. The proposed relaying scheme is tested for various fault conditions in a 20 kV Iranian radial EDN containing DG units at different locations. It is shown that the proposed scheme is not affected by the presence of DG units whereas the conventional relays fail the protection coordination. The proposed characteristic maintains proper recloser-fuse coordination for all fault types and different DG conditions. Keywords: Fuse saving, distributed generation, electric distribution network, non-communication protection, self-adaptive relaying scheme IntroductionFuse saving is a common protection strategy that prevents nuisance fuse blowing during transient faults by fast operation of the recloser located at the head of a feeder before the blown up of its downstream fuses. After a predefined time, enough for the fault clearance, the recloser reenergises the feeder and restores the power supply. Since 50% to 80% of faults occurring in electrical distribution networks (EDNs) have transient nature [1], the fuse saving strategy can improve the system security and reliability. By incorporation of distributed generation (DG) units in EDNs, the fault current level and direction can change and cause miscoordination between the recloser and its downstream fuses. The fault current passing through the recloser decreases and at the same time the fuse fault current increases because of the DG contribution to the fuse fault current [2]. Therefore, the fuse may blow up before the fast operation of the recloser.Several methods are presented in the literature for fuse-recloser coordination in the presence of DG. In [3, 4] a complete study is carried out on a test EDN to find the best DG locations and also the best recloser setting to minimise the loss of coordination between the fuse and the recloser under different fault conditions. In order to achive the best location and size of DG, different cases must be studied by changing DG size and location for each possible fault location. This method needs to be tailored for each EDN individually. In addition, any change in the number of DG units, can cause a miscoordination between the recloser and fuses. Thus, it may be very time consuming or even infeasible to find the best DG location and related recloser setting for large EDNs.The method of [5] uses power electronic switches to disconnect all DG units after a fault inception and before any fuse blow up. This method does not require any upgrade of the prote...

Fuse saving scheme in highly photovoltaic‐integrated distribution networks

“…V recl,F is locally measured using the potential transformer installed at the main substation. –The exponential function prevents the operating time of recloser reduces to zero when a fault occurs at the beginning of the feeder. In Jamali and Borhani‐Bahabadi, due to use of V recl,F in the numerator of modification term, the recloser operating time is zero for the zero voltage condition, as shown in Table . –Since the modified operating time of recloser should be proportional to the voltage drop at the beginning of feeder, the recloser should operate fast for the faults occurred near its location due to significant voltage drop while in the case of a fault far from the recloser location, its operating time increases. To satisfy this principle, the term of 1− V recl,F should be included in the exponential function of modification term.…”

“…The study results are shown in Table . OCBMT strategy enhances the performance of current‐based modification term proposed in Shah and Bhalja while OVBMT strategy enhances the performance of voltage‐based modification terms proposed in Saleh et al and Jamali and Borhani‐Bahabadi . In comparison with Shah and Bhalja, OCBMT strategy allows for more PV sources without protection miscoordination.…”

“…Borhani-Bahabadi. [29][30][31] This group reduces the operating time of the fast operation curve of the recloser using a voltage term. Similar to the previous group, this method requires the microprocessor-based reclosers.…”

“…OCBMT strategy enhances the performance of current-based modification term proposed in Shah and Bhalja 27 while OVBMT strategy enhances the performance of voltage-based modification terms proposed in Saleh et al 28 and Jamali 0 235 261 302 334 361 388 10 230 250 294 328 350 380 20 227 241 283 321 341 373 30 221 232 276 312 335 370 40 214 220 267 304 326 364 50 203 211 255 296 318 357 60 195 201 243 291 304 350 70 183 193 231 285 295 341 80 176 182 220 273 287 333 90 168 174 208 261 280 325 100 161 168 199 256 273 314 and Borhani-Bahabadi. [29][30][31] In comparison with Shah and Bhalja, 27 OCBMT strategy allows for more PV sources without protection miscoordination. Also, OVBMT strategy provides the possibility of installing more PV sources compared with Saleh et al 28 and Jamali and Borhani-Bahabadi [29][30][31] with preserving the coordination between fuse and recloser in the worst case of DN short-circuit fault and maximum PL of PV systems.…”

“…[29][30][31] In comparison with Shah and Bhalja, 27 OCBMT strategy allows for more PV sources without protection miscoordination. Also, OVBMT strategy provides the possibility of installing more PV sources compared with Saleh et al 28 and Jamali and Borhani-Bahabadi [29][30][31] with preserving the coordination between fuse and recloser in the worst case of DN short-circuit fault and maximum PL of PV systems. It verifies that the proposed scheme facilitates the integration of higher PL of PV units into DN.…”