Over Current Relays (OCRs) and Directional Over Current Relays (DOCRs) are widely used for the radial protection and ring sub transmission protection systems and for distribution systems. All previous work formulates the DOCR coordination problem either as a Non-Linear Programming (NLP) for TDS and Ip or as a Linear Programming (LP) for TDS using recently a social behavior (Particle Swarm Optim...

Directional over current relays (DOCR) are commonly used in power system protection as a primary protection in distribution and sub-transmission electrical systems and as a secondary protection in transmission systems. Coordination of protective relays is necessary to obtain selective tripping. In this paper, an approach for efficiency reduction of DOCRs nonlinear optimum coordination (OC) is p...

The mechanisms by which telomeres are distinguished from DNA double-strand breaks are poorly understood. Here we have defined the minimal requirements for the protection of telomeric DNA ends from nonhomologous end-joining (NHEJ). Neither long, single-stranded overhangs nor t loop formation is essential to prevent NHEJ-mediated ligation of telomeric ends in vitro. Instead, a tandem array of 12 ...

the non-differentiability and implicit definition of boundary of production possibility set (pps) in data envelopment analysis (dea) are two important difficulties for obtaining directional characteristics, including different elasticity measures and marginal rates of substitution. also, imposing weight restrictions in dea models have some shortcomings and misunderstandings. in this paper we ut...

Power system protection in electrical power engineering aims at eliminating a faulted part in an electric network from an otherwise healthy power system. Protection coordination involves a process of best timing any faulted currents so as to reduce the extension of outage areas to a minimum after a fault clearance. In the paper, innovative protection methods and devices widely based on computer...

Abstract Charge structure, which can instantly release much energy, is a significant research point in explosive protection and warhead. A nonaxisymmetric directional-focusing warhead based on quadrangular charge structure was designed, the distribution of fragments from involved studied. Numerical calculation carried out ABAQUS finite element software. The witness targets were obtained an equa...

Abstract After the fault circuit breaker at end of long line large mode operation system fails, composite voltage sensitivity 220 kV and above double bus connection failure protection is insufficient, release complex locking function needs to be switched on off manually, which cannot automatically adapted after changes. To solve this problem, compound logic cancelled, zero negative sequence pow...

Most studies in relay coordination have focused solely on coordination of overcurrent relays while distance relays are used as the main protection of transmission lines. Since, simultaneous coordination of these two types of relays can provide a better protection, in this paper, a new approach is proposed for simultaneous coordination of distance and directional overcurrent relays (D&DOCRs). Al...