###### Abstract  
Electric power distribution networks are generally radial in nature, with unidirectional power flows transmitted from the highest voltage levels to the consumption levels. The protection system in these distribution networks is relatively simple and consists mainly of fuses, reclosers (RC) and overcurrent relays (OCRs). The installation of distributed generation (DG) in a network causes coordination problems between these devices, because the power flows are no longer unidirectional and can flow upstream to the substation. For this reason, the work proposed here analyzes the most significant impacts that DG has on the protection devices and proposes an adjustment method for the OCRs based on linear programming (LP) techniques with the aim of improving their response time to the different faults that may occur in the main feeder of the network. The distribution system selected for the study is the IEEE 34 bus system using DlgSILENT 14.1 software for its modeling and Matlab for the adjustment of the overcurrent devices. Results indicate that better coordination between protection devices are achieved if LP is used.  
adaptive protection; distributed power generation; power distribution; power system protection [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], S.  
power and therefore its effect on the protection system [9], others recommend reconfiguring the network topology [10; 11], or the use of fault current limiters (FLCs) [12; 13].  
In recent years, mitigation methods based on coordination algorithms have been developed using linear programming (LP), non-linear programming (NPL), or genetic algorithms (GA) [14; 15; 16; 17] that either modify the coordination interval time (CTI) between devices, determine the optimal location of the DG [15], or in combination, without compromising the protection system.  
Although these methods can be effective, they have some disadvantages and limitations. Therefore, the disconnection of the DG immediately before fault detection proposed in [3; 18], can cause asynchronous reconnections and cause severe damage to both the DG and the distribution network, especially at high penetration levels [3; 10]. The limitation of the DG capacity proposed in [9] is also undesirable, since it also limits the penetration level and therefore the advantages of its installation close to the consumption points, (loss reduction, improvement of supply quality, etc.). The network reconfiguration suggested in [10; 11] is costly and sometimes unfeasible. Finally, the use of current limiters [12; 14] entails an additional installation cost that can be prohibitive.  
Regarding the use of NLP methods for the determination of the coordination index mentioned in [15] can be very complex, particularly if the number of protection devices and DG's is high, since the calculation time required to determine their operating parameters will also be high [19; 20; 21], on the other hand, not always the optimal location point of DG is viability from the perspective of network operation, e.g., availability of power evacuation at the point of common connection (PCC).  
The investigations described in [14; 16; 17], use GA-based optimization algorithms to determine optimal coordination between OCR and distance relays [14]. In [16] a hybrid GA and NLP algorithm is developed to choose the optimal value of DIAL or time multiplier setting (TMS) of all OCR, the use of a continuous genetic algorithm (GAC) faster than GA for the same purpose is developed in [17]. However, all the optimization algorithms described do not consider DG.  
In the present work:  
* the most significant impacts that DG causes on protection devices are analyzed,
* an adjustment method for OCRs based on LP techniques is proposed,
* the analysis is carried out by using the IEEE 34-node test feeder system modeled in DIgSILENT PowerFactory.  
As far as the authors know, it seems that there is a lack of similar studies in the available literature.