الفهرس 
Proposed Adaptive Distance Relaying Schemes For Interconnected Transmission Lines Compensated With Thyristor Controlled Series Capacitor
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Abstract
The protective relay philosophy is the art of managing relay operation to guarantee the dependability and security of its function. Distance relays are the most superior protection devices for transmission lines (TLs) worldwide. The key advantage for that is the independency of its fault coverage for the protected line on the source impedance changes.
The series compensation (SC) is the most common techniques used in TLs, as it does not only improve system transient stability, control voltage and power flow, but also, increases power transferring capacity, and decreases losses. Thyristor Controlled Series Compensator (TCSC) provides better control over fixed SC for a TL power flow. But, unfortunately the integration of TCSC in TL affects its protection aspects significantly due to the abrupt line parameters changes. This will lead to defect the apparent impedance measured by the distance relays that cause overreach/underreach of the relays.
This thesis embraces the idea of improving the performance of distance relays protecting TCSC compensated lines by introducing two different approaches. The key objective of these approaches is to alleviate TCSC effect on both Mho and Quadrilateral relays to acquire each characteristic feather by developing a dynamic characteristic for both to accommodate the fault system conditions. These potential schemes use the investigated TCSC compensated factor based on practical TCSC design in their calculations. According to this investigated factor, a comprehensive study was carried out at first to determine the influence of the TCSC on both Mho/Quadrilateral distance relays under different fault conditions.
The first proposed approach, is a Mho relay scheme based-phase comparator scheme using positive-sequence voltage polarization with memory (PSMV) method. The proposed relay uses a suggested impedance index factor to initiate fault detection subroutine. As well as, the positive sequence current of faulted loop and TCSC terminal current are used to identify whether the TCSC is included in the faulted loop or not before applying the scheme. Then the proposed PSMV scheme updates its equations to accurately detect the fault in the right zone.
The second proposed approach, is a two-fold adaptive dynamic Quadrilateral relay. It is developed by investigating a new tilt angle and modifying the Takagi method to recognize the fault zone identifier, while the proposed relay adapts its reactive reach and resistive reach separately and independently. The investigated tilt angle and identified fault zone use the TCSC reactance to compensate its effect on the TL parameters and system homogeneity.
The proposed schemes are extensively tested on two standard transmission networks, IEEE 9-bus, and IEEE 39-bus. The simulations are accomplished on Matlab environmental simulator. The schemes are tested for different fault types, fault locations that cover the three zones of protection, and different TCSC modes of operation (bypass, inductive, capacitive, and blocking modes).
The achieved results designate the precision of the proposed schemes. Moreover, the results indicate their effectiveness compared with conventional relays. By getting use of technical benefits of the proposed schemes, they could be used for updating, improving, and refurbishing of the existing distance relays for both Mho and Quadrilateral relays’ characteristics.