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This paper presents a novel traveling wave protection scheme to satisfy the sensitive and high‐speed performances of protective relaying for line commutated converter high voltage direct current (HVDC) transmission lines. The scheme performs by using a startup and two auxiliary criteria with a small sampling interval to ensure the sensitivity of fault detection: the startup criterion adopts the concept...
Circulating current unbalance of double-circuit transmission line (DCTL) on the same tower has a vital effect on relay protection, especially in the short line. In this paper, a mathematical method based on phase-mode transformation is proposed to calculate unbalance of DCTL and explain the phenomenon that circulating unbalance degree is nearly insusceptible by the line length and load level. The...
To verify the rationality of networking and the real-time reliability of network transmission for the process level in smart substation, this paper proposes a method of modeling and simulating for smart substation based on OPNET, which models the key network equipments after analyzing the simulation requirement of process level network in smart substation. And several networking modes and optimization...
It is the key problem in automatic voltage control of large-scale power grids to quantitatively assess the reactive power regulation capability of provincial power grid to determine the control range of reactive power between provincial and regional power grids. Based on the concept of layered decoupling, firstly the definition of average coordination power factor limits (ACPFL) is given to evaluate...
In this paper, real time performances of process level networks based on IEC61850 SCSM (Specific Communication Service Mapping) Model are analyzed. IEC61850 SCSM Model which is different from Ethernet OSI (Open System Interconnect) Model of Ethernet is introduced by IEC61850. Firstly, dominating factors of real time performances of process level networks are studied. Then IEC61850 SCSM Model is amplified...
HVDC line protection system is composed of traveling wave protection as the main protection, under voltage protection and differential protection as the backup protection. The responses of the HVDC line protection criterion are not same at different fault situations, and it also makes the operation characteristics of the line protection quite different. In this paper, based on the EMTDC simulation...
In this paper we show that the HVDC converter transformer valve side has the diversity and space-time discrete. Considering the influence of failure time on the fault feature, this paper proposes a method of fault feature stage dividing. The basis of fault feature stage dividing is given, and simulation result is showed for comparison. The protection test and BPP strategy research is also discussed...
This paper presents the power system fault calculation model for multi-circuit lines with mutual zero-sequence impedance and describes the procedure of the common and integrated node zero-sequence admittance matrix. It makes the complex fault calculation be able to extend faulted location into the inside of coupling lines. The transformation for 4-circuit coupling lines from sequence-component model...
This paper presents a new state estimation method in rectangular coordinates to solve the problem of lacking data redundancy of wide-area measurement/monitoring system (WAMS). This method utilizes all the measurements of WAMS and partial equivalent current phasor measurements transformed by flow measurements from SCADA system. The iterative formula is proposed and analyzed based on these mixed measurements...
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