Doaa Khalil Ibrahim

Nuclear Power Reactors (NPRs) are large in scale and complex, so the information from local fields is excessive, and therefore plant operators cannot properly process it. When a plant malfunction occurs, a great data influx is occurred, so the cause of the malfunction cannot be easily or promptly identified.
A typical NPR may have around 2,000 alarms in the Main Control Room (MCR) in addition to the display of analog data. During plant transients, hundreds of alarms may be activated in a short time. Hence, to increase the plant safety, this paper proposes a support system based on neurofuzzy that assists alarming and diagnosis systems. Throughout this framework the neurofuzzy fault diagnosis system is employed to fault diagnosis of nuclear reactors. To overcome weak points of both linguistic and neuro learning based approaches, integration between the neural networks and fuzzy logic has been applied by which the
integrated system will inherit the strengths of both approaches.

The extracted power from wind is clean, plentiful, and completely renewable. All over the world, researchers keep looking for the best layouts of wind parks to maximize captured energy. To design wind farms suitably, forecast their performance, and understand the strain loads of wind turbines, there is a persistent need to catch a perfect wake model. Wind turbine wakes are one of the most vital factors in the meteorology of wind power due to reducing the power production and the necessity to raise the downstream capacity of wind turbines. This study is divided into two main aspects: firstly, enhancing the optimal layout for the wind turbines at a farm using Marine Predators Algorithm (MPA). The Jensen wake model is applied to get the extracted power for each turbine, which is one of the mutual analytic models used to reach the optimized layout. By comparing the performance of the proposed algorithm with the previous studies achieved by several techniques, the obtained results revealed that the MPA achieves promising results. Secondly, the proposed algorithm is applied for four sites in Egypt as the fraction of occurrence for the selected locations has been adequately calculated using wind speed over five years.

Nowadays, integrating large scale renewable energy sources, like solar PV parks, raises challenges for Load Frequency Controllers (LFC). The output of PV varies continuously, which requires a robust LFC deals
logically without continuous tuning and parameters optimization. In this paper, a fuzzy logic controller (FLC) is proposed to act as the main LFC instead of the traditional proportional–integral–derivative (PID) controller. The dynamic performance of FLC is enhanced by optimizing its parameters for different cost functions using particle swarm optimization technique (PSO). Another two FLCs will be added to PV system to act as an output controller instead of maximum power point tracker (MPPT) to enhance the overall system performance. To increase system reliability, a fast active power source called redox flow battery (RFB) is added in the proposed model as a frequency stabilizer. RFB can deeply discharge up to 90% with theoretically limitless number of duty cycles and has fast time response for severe load changes. The
importance of these proposed controllers side by side with RFB is to avoid disconnecting solar parks during
heavy cloudy days while preserving on maximizing its output during these periods. The superiority of the proposed FLC is examined by evaluating its performance compared to another control approach called PID-P (PID controller with P controller in the inner feedback loop). Finally, a comprehensive sensitivity analysis is also presented to investigate the controller robustness for extensive changes in power system parameters and loading.

Detection and location of open conductor in transmission systems using single-end data is a challenging task. This paper proposes a novel integrated scheme to detect and locate different types of open conductor faults (OCFs) in HV transmission systems. The proposed scheme unit (PSU) applies Discrete Wavelet Transform (DWT) with single-level decomposition on local current signals to detect OCFs correctly using adaptively estimated threshold values. PSU is also capable of dealing correctly with various normal transient conditions such as load capacitor switching. To ensure quick repair of OCFs, PSU captures the transient voltage surges and applies a fault location scheme using DWT and Clark Transformation to accurately estimate the location of different OCFs types. Extensive ATP simulations are employed to check the PSU performance under various OCFs conditions on a 345 kV, 100 km transmission line. The achieved results confirm the effectiveness, robustness, and reliability of PSU in detecting correctly OCFs as well as the low-impedance faults within only 1.25 cycles. Moreover, the percentage error in estimating OCFs location is less than 1%. PSU has also confirmed its capability to be applied in cascaded lines without any communication or synchronization between PSUs.

This paper introduces a novel online adaptive protection scheme to detect and diagnose broken bar faults (BBFs) in induction motors during steady-state conditions based on an analytical approach. The proposed scheme can detect precisely adjacent and non-adjacent BBFs in their incipient phases under different inertia, variable loading conditions, and noisy environments. The main idea of the proposed scheme is monitoring the variation in the phase angle of the main sideband frequency components by applying Fast Fourier Transform to only one phase of the stator current. The scheme does not need any predetermined settings but only one of the stator current signals during the commissioning phase. The threshold value is calculated adaptively to discriminate between healthy and faulty cases. Besides, an index is proposed to designate the fault severity. The performance of this scheme is verified using two simulated motors with different designs by applying the finite element method in addition to a real experimental dataset. The results show that the proposed scheme can effectively detect half, one, two, or three broken bars in adjacent/non-adjacent versions and also estimate their severity under different operating conditions and in a noisy environment, with accuracy reaching 100% independently from motor parameters.

This paper proposes an adaptive dynamic Mho distance relay based on a phase comparator scheme for protecting interconnected transmission networks compensated with a Thyristor Controlled Series Capacitor (TCSC). The proposed relay uses an impedance index factor to initiate the fault detection subroutine. The RMS of the positive sequence current of the faulted loop and the TCSC terminal current are compared for TCSC zone identification. A phase comparator for ground and phase distance elements is proposed, relying on the positive sequence voltage as a polarized memory quantity, while the operating and polarizing quantities are developed using estimated TCSC impedance to mitigate its negative impact. The proposed scheme is easy in implementation and independent on synchronized data transfer, as minimum communication requirements are needed. To evaluate the performance of the proposed scheme, extensive simulation studies were carried out on an IEEE9 bus system compensated with TCSC for different firing angles covering four modes of TCSC operations, different fault types, and fault locations. In addition, an IEEE-39 bus network, as a large interconnected system, is tested for validation purposes. The achieved results designate the precision of the proposed scheme. Moreover, the results indicate its effectiveness for fault resistance tolerance, close-in three phase faults, and stable power swing phenomenon compared with conventional relays.

Power swing is a power system transient phenomenon that arises due to several reasons including line switching, line outage, sudden increment or decrement in load, faults, etc. Unnecessary tripping during power swing and unnecessary blocking for faults occur during power swing result in distance relay maloperation. Several cascaded outages and major worldwide blackouts have occurred due to maloperation of distance relays. This paper proposes a technique for supervising distance relays during power swing. The proposed
online technique discriminates real faults and power swing accurately. It relies on constructing a locus diagram for the current and voltage differences (ΔI-ΔV) between the two ends of the protected line. The locus is estimated at every power frequency cycle to continuously monitor the state of the line by utilizing the synchrophasor measurements at the sending and receiving ends of the line. The proposed technique is tested for two-area, four-machine power system under faults at different locations of zone-1 and zone-2 regions of distance relays, fault resistances, fault inception angles and slip frequencies using MATLAB software. The simulation results proved the superior improvement of distance relay performance for handling power swing blocking and unblocking actions.

This paper presents an accurate fault location scheme for transmission systems consisting of an overhead line in combination with an underground power cable. The algorithm requires phasor measurements data from one end of the transmission line and the synchronized measurements at the most far end of the power cable. Fault location is derived using distributed line model, modal transformation theory and Discrete
Fourier Transform. The technique can be used on-line or off-line using the data stored in the digital transient recording apparatus. The proposed scheme has the ability to locate the fault whether it is in the overhead line or in the underground power cable. Extensive simulation studies carried out using MATLAB show that the proposed scheme provides a high accuracy in fault location under various system and fault conditions.

This paper presents an adaptive fault location scheme for aged power cables using synchronized phasor measurements from both ends of the cable. The proposed fault location scheme is derived using the two terminal synchronized measurements incorporated with distributed line model, modal transformation theory and Discrete Fourier Transform. The proposed scheme has the ability to solve the problem of cable changing parameters, especially the change of the relative permittivity over its age and thus for the operating positive, negative, and zero-sequence capacitance changes. Extensive simulation studies are carried out using Alternative Transients Program ATP/EMTP. The simulation studies show that the proposed scheme provides a high accuracy in fault location calculations under various system and fault conditions. The results show that the proposed scheme responds very well to any fault insensitive to fault type, fault resistance, fault inception angle and system configuration. The proposed scheme solves the problem of aged cables with the change of the electric parameters. In addition to, it gives an accurate estimation of the fault resistance.

Reliable and accurate fault location algorithms for series-compensated transmission lines are challenges that arise in most of modern electrical power transmission grids. This paper proposes an accurate fault location algorithm for series-compensated transmission lines. Distributed parameters long transmission line model is used in this study to account for practical travelling waves’ effect during fault incidence. The proposed algorithm uses wavelet transform for only one cycle data window length of post-fault voltage signals to detect the faulted line, then Fast Fourier Transform for voltages and currents signals of three post-fault cycles (including the 1st cycle) to locate the fault. Only positive sequence network is used for the fault location calculations, hence, the algorithm does not depend on the zero sequence parameters (i.e., ground resistivity) which are depending on moisture, temperature, etc. Different types of grounded and ungrounded faults, fault locations, fault resistances, fault inception angles are applied to validate the robustness of the algorithm. The algorithm is tested using a real case study for a 380 kV, 400 km series compensated transmission line in Saudi Arabia using MATLAB and SIMULINK software. Extensive Simulation results show the effectiveness and robustness of the proposed algorithm under various fault conditions.