Total System Collapse Research Articles

FACTS Devices as a Solution to Power Industries Problems: A Review

With an ever-increasing demand for power and establishment of new industries with high load demand, the need to for constant upgrade of powers system network is high. Such transmission networks are prone to external disturbances from loads, environment and other sources which leads to low power quality. Sudden application or removal of large loads. Large loads are known to draw more reactive power than the generated reactive power which lead to reactive power imbalance which can lead to total system collapse. In this paper, a critical review of how Flexible Alternating Current Transmission Systems (FACTS) devices are used to mitigate such issues to ensure power quality is done. Previous work on the integration of different FACTS devices were review to establish the advantage of FACTS devices over conventional solutions to power transmission problems.

A Proactive Decision-Making Model for Evaluating the Reliability of Infrastructure Assets of a Railway System

Railway infrastructure is generally classified as either fixed or movable infrastructure assets. Failure in any of the assets could lead to the complete shutdown and disruption of the entire system, economic loss, inconvenience to passengers and the train operating company(s), and can sometimes result in death or injury in the event of the derailment of the rolling stock. Considering the importance of the railway infrastructure assets, it is only necessary to continuously explore their behavior, reliability, and safety. In this paper, a proactive multi-criteria decision-making model that is based on an interval-valued intuitionistic fuzzy set and some reliability quantitative parameters has been proposed for the evaluation of the reliability of the infrastructure assets. Results from the evaluation show that the failure mode ‘Broken and defective rails’ has the most risk and reliability concerns. Hence, priority should be given to the failure mode to avoid a total system collapse.

Analysis of Power System Transient Stability of the Nigerian 330-kV Electricity Grid

Faults on power system are inevitable and can occur at any time resulting into transient instability. Transient instability can cause loss of synchronism and possible damage to power equipment and consumer loads. Therefore, this study analyzed the transient stability (TS) of the Nigerian 330-kV, 34-bus power network. Power flow and swing equations describing the system steady and transient states were respectively analyzed using Newton-Rahpson and Runge-Kutta, fourth order numerical techniques to provide linear solution due to their non-linearity. Simulations were done and swing curves for different fault conditions obtained. The critical clearing time at which the simulated faults were cleared was determined. The results of load flow analyses revealed that buses 6, 10, 13, 14, and 17 with respective voltage magnitude of 0.937, 0.921, 0.938, 0.829 and 0.780 per unit violated voltage tolerance limit of 0.95 to 1.05 p.u. The system total active and reactive power losses were 57.62 MW and -70.62 MVar respectively. The obtained swing curve showed that for fault on bus 11 [line 9-11] generators 2, 3 and 7 lost synchronism after 1.0 s but other generators retained their stability. Similarly, for fault on bus 13 [line 10-14] generators 3 and 7 lost synchronism but other generators retained stability after 0.4 s. These results indicate that faults occurrence on generating stations of power system is unavoidable, but the clearance time must be short (few seconds) to avert total system collapse and loss of synchronism.

Verification of Seismic Response Modification Factors of Uncoupled Composite Plate Shear Walls/Concrete Filled

In this paper, the seismic design factors for uncoupled composite plate shear walls/concrete filled (C-PSW/CF), a.k.a. SpeedCore, are verified by conducting a study using FEMA methodology. These are the seismic response modification factor, R, the deflection amplification factor, Cd, and the overstrength factor, Ωo; and their values for C-PSW/CF are specified as 6.5, 5.5, and 2.5, respectively. A study was needed, as these factors for uncoupled C-PSW/CFs, included in ASCE 7 since as far back as its 2000 edition, were chosen solely based on the seismic performance of similar structural systems and engineering judgment of the committee members. For this study, four archetypes with planar walls and three archetypes with C-shaped C-PSW/CF walls were chosen. Two different damage measures (DM) were chosen for this study; namely, 3% and 5% maximum interstory drifts. Based on FEMA methodology, all archetypes satisfied the specified performance requirement considering a “good” rating for total system collapse uncertainty (βTOT).

Application of Internet of Things (IoT) in Nigerian Power Grid Management

The importance Internet of Things (IoT) in managing the Nigeria 330kV power grid cannot be overemphasized. The nation’s power sector has been deviled with problems ranging from low voltages to total system collapse. There have been efforts to reverse the negative trends. One of the efforts was the development of robust modern technologies to monitor and control the systems in real time. Another challenge of note is the lack of visibility with the grid controller, which can be compared to driving a car with blurred windscreen. The existing SCADA system has lower coverage and parades about 22% visibilities to control operators. Internet of things (IoT) is machine to machine connection via the internet for the purpose of controlling, monitoring and exchanging information. A lot can be achieved via IoT like controlling remote actuators, sensing of remote device’s parameters such as temperature, position, voltage, current, and power. It helps controllers at the master stations or control centers to make informed decisions for better grid stability. The paper explains the design and implementation of the IOT based solution to the problems. It describes its components and deployment in twenty-nine power stations in Nigeria. The paper discloses that the application of the homegrown solution has brought visibility and stability to the Nigerian power grid network.

A Decentralized Intrusion Detection System for Security of Generation Control

Recently, several incidents have been reported relating to security breaches in the power system network. As the operation of the automatic generation control (AGC) system fully depends on communication technologies, any compromise in its functionality could lead to total system collapse. For example, the intruders may target the communication network of the legacy grid by launching deception and data-availability attacks, which have the potential to manipulate the crucial telemetered quantities, such as wide-area sensor measurements and (or) the control signals. Despite significant work on AGC security, most of the past studies were limited to the detection of intrusions in sensor measurements, and less emphasis is given to addressing the impact of attacks on control signals. To this end, this article proposes a decentralized intrusion detection system (IDS) that jointly identifies data anomalies in the sensor measurement and the control signals. The IDS is powered by a novel machine learning (ML) classifier, which we call cluster-driven ensemble learning (CDEL) algorithm. The proposed CDEL is based on the ensemble principle that combines the predictive power of multiple support vector machines and the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$K$ </tex-math></inline-formula> -means clustering algorithm. Experimental results reveal the supremacy of CDEL over existing state-of-the-art ML techniques.

Power System Stability Enhancement Using a Novel Hybrid Algorithm Based on the Water Cycle Moth-Flame Optimization

Poor control of the power grid can lead to a total system collapse, causing significant economic losses and possible damage to security and social peace. Therefore, improving power system stability, particularly transient stability, has become one of the major research topics. This paper proposes a developed modeling approach that provides the optimal stabilizer parameters of the control devices, aiming at improving the electrical network stability by minimizing the angular speed deviation in the presence of a severe disturbance event using a novel hybrid algorithm called Water Cycle-Moth Flame Optimization (WCMFO). The main advantages of the proposed method are the speed of response and its efficient exploration and exploitation ability to attain the best solution quality. This is achieved by imposing a thermodynamic incident (an abrupt change in mechanical torque) on the well-known test model (SMIB), Single Machine Infinite Bus. To test the effectiveness of the proposed method, Power System Stabilizer (PSS), Proportional-Integral-Derivative (PID-based PSS), and Fractional Order-PID (FOPID-based PSS) are implemented to control and ensure the system’s ability to return to a stable state in the presence of this fault. The achieved experimental outcomes have proven the superiority, and efficiency of the developed approach (WCMFO) in terms of damping the oscillations and reducing the overshot, with an improvement of 44% over the Water Cycle Algorithm (WCA), Moth-Flame Optimization (MFO), and Artificial Ecosystem Optimization (AEO). It is envisaged that the proposed method could be very useful in the design of a practical high-performance power system stabilizer.

A New Load Shedding Scheme With Consideration of Distributed Energy Resources’ Active Power Ramping Capability

This paper presents a novel load shedding scheme with consideration of the active power ramping capability of Distributed Energy Resources (DERs) to address the challenges due to low inertia and diverse types of DERs in microgrids. In the paper, it is demonstrated that due to the small inertia in microgrids, even with sufficient reserve power, the frequency could rapidly drop to a low level and trigger the DERs’ under frequency protection (thus the total system collapse), if the reserve active power is not ramped up at a sufficient rate. The proposed load shedding scheme addresses this challenge by considering not only the DERs’ reserve, but also their speed in injecting active power to the system to determine the amount of load should be shed, so that critical frequency thresholds are not violated. The proposed load shedding scheme is tested using a realistic real time hardware-in-the-loop arrangement. The results show that the proposed scheme can correctly detect the cases when the DERs’ responses are too slow and trigger the required load shedding actions, thus effectively containing the frequency above the critical threshold.

Real-time intelligent control and cascading failure prevention in microgrid systems based on neural network algorithm: an experimental approach

This paper presents an intelligent control method based on artificial neural network (ANN) to prevent cascading failures and blackout in microgrid systems after N1 contingency condition. Microgrids have low inertia as compared to the utility power grids which makes their control very challenging. The main contribution of this work is to utilise the machine learning structure of ANN to prevent blackout and make microgrids more reliable and resilient. This method is able to relieve the congestion on lines by adaptive power re-dispatch to prevent consecutive line outages. The proposed ANN control approach is tested on an experimental test system. Experimental results show that the ANN approach provided accurate and robust control and management of the microgrid system by preventing a total system collapse. The technique is compared to a heuristic multi-agent system (MAS) approach based on communication interchanges. The ANN showed a faster and better response than the MAS.

Voltage Collapse Prediction for Egyptian Interconnected Electrical Grid EIEG

Voltage collapse is an undesired phenomenon that occurs due to voltage instability and is generally associated with weak or stressed system (heavily loaded lines), long lines, radial networks, faults and/or reactive power shortages. Its occurrence is not frequent in developed countries despite their large and complex networks but its frequency is high in Egypt. Voltage collapses are highly catastrophic anytime they occur. On the Egyptian Interconnected Electrical Grid EIEG, the system collapse phenomenon is frequently experienced and often leads to either partial or total system collapse blackout, which greatly impairs the nation's socio-economic development and industrialization. This high rate is due to the fact that the EIEG is weak, highly stressed, long and radial in nature hence lacking flexibility. The analysis is performed for EIEG power system. Modern advances in technology are changing the way utility industry increase the transmission of power throughout the country. Distributed energy resources are constantly improving their reliability and power capabilities. The model analysis technique is performed for system using the constant load model. The simulation results are Q-V curves on weak voltages by Power World Simulator PWS Software and Matlab Program.

Performance Comparison of Voltage Stability Indices for Weak Bus Identification in Power Systems

Voltage collapse event is identified as complex and localized in nature but its effect is extensive once occurred. The vital effect of voltage collapse would be the total system collapse or blackouts which would cost a large loss to utility companies. Eventually, on- line monitoring of power system stability has become an important factor for electric power utilities. The last utmost option to avert voltage collapse incident from occurring is by the implementation of under voltage load shedding scheme. The identification of location for load shedding is the main motivation of the study. The weakest bus in a power system is identified as the location for load shedding. This location is obtained using voltage stability index Ld. The performance and effectiveness of Ld index is compared with Fast Voltage Stability Index (FVSI) and Le Index. The results obtained indicate that Ld Index can be used to identify the weak bus in a power system and consequently for the placement of UVLS relays in a power system network.

On the quantification of seismic performance factors of Chevron Knee Bracings, in steel structures

As a matter of fact, it is necessary to have the values of Response Modification Factor R, Over-strength Factor Ω0, and Deflection Amplification Factor Cd in order to design seismic-force-resisting systems according to design and loading codes. This study is intended to evaluate these factors for a structural lateral bracing system called Chevron Knee Bracing (CKB). In this type of bracing, the knee elements assist the system to dissipate energy through the formation of plastic flexural and/or shear hinges within the presented bracing system. The approach utilized in this study is according to FEMA P695 based on low probability of structural collapse and involves nonlinear static and dynamic analyses. Over-strength and ductility of this type of bracing is investigated through performing nonlinear static analyses. Conducting Incremental Dynamic Analyses (IDA), Collapse Margin Ratios (CMRs) of the defined archetypes model are achieved and modified to obtain an Adjusted Collapse Margin Ratio, ACMR for each archetype. The values of calculated ACMRs are compared with the accepted values proposed by FEMA P695 in which the total system collapse uncertainty is considered to prove the validity of presumed seismic performance factors of CKB systems.

DFIG rotor voltage control for system dynamic performance enhancement

This article develops a model of a doubly fed induction generator system including the detailed dynamics of the converter circuitry. The order of the converter controls in terms of providing damping to the system is identified through residue principles. Supplementary damping controller has been incorporated so as to compensate for the phase lag introduced by the rotor voltage input, which was observed to have the largest residue contribution at the lightly damped mode. The improvement in damping profile was verified by simulating the system for a number of disturbance conditions. While the power oscillation damping (POD) controller was observed to enhance the system damping generally, it was also able to ride through low voltage conditions arising out of severe fault conditions thus averting total system collapse.

Wanted: A more intelligent grid

This paper presents keys in avoiding total system collapse though enhancing grid reliability and stability with a better, smarter, faster SCADA system.

Habitat fragmentation resulting in overgrazing by herbivores

Habitat fragmentation sometimes results in outbreaks of herbivorous insect and causes an enormous loss of primary production. It is hypothesized that the driving force behind such herbivore outbreaks is disruption of natural enemy attack that releases herbivores from top-down control. To test this hypothesis I studied how trophic community structure changes along a gradient of habitat fragmentation level using spatially implicit and explicit models of a tri-trophic (plant, herbivore and natural enemy) food chain. While in spatially implicit model number of trophic levels gradually decreases with increasing fragmentation, in spatially explicit model a relatively low level of habitat fragmentation leads to overgrazing by herbivore to result in extinction of the plant population followed by a total system collapse. This provides a theoretical support to the hypothesis that habitat fragmentation can lead to overgrazing by herbivores and suggests a central role of spatial structure in the influence of habitat fragmentation on trophic communities. Further, the spatially explicit model shows (i) that the total system collapse by the overgrazing can occur only if herbivore colonization rate is high; (ii) that with increasing natural enemy colonization rate, the fragmentation level that leads to the system collapse becomes higher, and the frequency of the collapse is lowered.

A predictive out-of-step protection system based on observation of the phase difference between substations

A recently developed predictive out-of-step protection system is described. The purpose of this protection system is to prevent total system collapse caused by step-out between large-capacity generator groups due to a serious fault in the trunk transmission line. This is accomplished by using online data collected during the incubation phase to predict a step-out and then issuing a system-seperation command. The system has the following characteristics: (1) the phase difference between several large generator groups is measured from online voltage data collected from substation busbars in the vicinity of the generators at a sampling rate of 600 Hz: (2) the phase difference at 200 ms in the future is predicted from the measured phase-difference data; and (3) if the predicted phase difference exceeds the instability threshold value, system separation if performed taking into account the power supply and demand balance after tripping.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>