Adaptive Protection System Research Articles

Relevance of adaptive protection scheme using phasor measurement unit in Indian power grid

The configuration of the power system is constantly changing due to renewable integration, changing loads, network switching operations or faults. The relays settings based on pre-determined static system conditions that are in general maximum or minimum, may not suffice, leading to inaccurate relay operation for a dynamic power system. Malfunction of conventional protection system has been one of the main causes of cascading catastrophes in power grid. Selection of suitable relay characteristics that will be an appropriate compromise for all loading conditions and contingencies is a matter of concern. The relevance of adaptive relay settings in wide area monitoring, protection, and control (WAMPAC) using synchrophasor is brought out in this paper. The significance of new wide area adaptive protection system (WAAPS) in improving the reliability and safety of power transmission through Indian grid, with a high level of operational uncertainties, is analysed and an architecture is suggested.

Three-Dimensional Base Isolation Using Vertical Negative Stiffness Devices

ABSTRACT A three-dimensional (3-D) base isolation system to control both the horizontal and vertical components of ground motion is presented in this paper. The system is adopting a negative stiffness device (NSD) that can be considered as an adaptive passive protection system, which can apparently change the stiffness of the structure. This work is focused on studying through numerical simulations the mitigation performance of the NSD against strong earthquakes in the vertical direction. The base isolation arrangement consists of elastomeric bearings acting both in the horizontal and vertical direction and NSDs acting only in the vertical direction. So, a 3-D base isolation is achieved, where it is assumed that the NSDs affect the vertical stiffness of the system only. Numerical analyses show that the presence of NSDs reduces the vertical acceleration in the structure. Nevertheless, accordingly with the passive control theory, the relative displacements increase. Therefore, it seems advisable a supplemental damping to mitigate this effect. Thanks to the presence of rubber isolators, it is possible to employ their inherent damping without introducing specific dampers in the vertical direction.

Alzheimer ’s Disease: Possible Mechanisms Behind Neurohormesis Induced by Exposure to Low Doses of Ionizing Radiation

In 2016, scientists reported that human exposure to low doses of ionizing radiation (CT scans of the brain) might relieve symptoms of both Alzheimer's disease (AD) and Parkinson disease (PD). The findings were unbelievable for those who were not familiar with neurohormesis. X-ray stimulation of the patient's adaptive protection systems against neurodegenerative diseases was the mechanism proposed by those authors. Now, some more recent studies performed in the field of neurobiological research confirm that low levels of stress can produce protective responses against the pathogenic processes. This paper outlines possible protective consequences of LDR in preventing the pathogenesis of AD through mechanisms such as restoring the myelin sheath and preventing neurodegeneration caused by oxidative stress. Focal demyelination is frequently reported in the proximity of beta-amyloid plaques within neocortex. Extracellular accumulation of amyloid is among well-characterized pathological changes in AD. It should be noted that LDR has been shown to contribute to the regeneration and functional recovery after transverse peripheral nerve injury (through inducing increased production of VEGF and GAP-43), which advances both the axonal regeneration and myelination. Another mechanism which is possibly involved is preventing neurodegeneration caused by oxidative stress. While high doses can induce reactive oxygen species (ROS) formation, oxidative stress and neuro-inflammation, substantial evidence now indicates that LDR can mitigate tissue damage through antioxidant defenses. Although adult neurogenesis has been reported to be beneficial for the regeneration of nervous system, some studies demonstrate that neurogenesis increases in AD brains. In spite of these reports, cellular therapy is introduced as a promising strategy for AD, and hence, LDR can affect the proliferation and differentiation of neural stem cells. Although such mechanisms are not fully known yet, it is hoped that this paper would foster further investigation into the mechanisms of this phenomenon, which accordingly improves human health.

INTEGRATED ASSESSMENT OF STABILITY FUNCTIONING COMPLEX TECHNICAL SYSTEMS IN THE TECHNO AND INFO SPHERE

The article deals with the issues of integrated assessment of complex technical systems stability functioning in techno sphere and info sphere. It is shown that the concept of cyber stability, including its components such as cyber reliability, noise immunity and cyber survivability are insufficiently investigated and defined. The formal definition is given and the scale with various gradation of cyber survivability is entered. On the example of robotic systems in form of drones two variants of mathematical models of cyber survivability estimation are considered. The first variant is related to the description of drones functioning in the conditions of computer attacks without impact protection systems. The second variant reflects the functioning of drones under the conditions of impacts in the presence of adaptive combined cybernetic protection system. In both variants, two strategies are considered - with minimal and maximum intensity of effects on the drone. It is concluded that proposed in the paper approach enables to evaluate the integrated stability of complex technical systems in the techno sphere and info sphere at the same time.

Adaptive Protection System for Microgrids Based on a Robust Optimization Strategy

The development of a proper protection system is essential for the secure and reliable operation of microgrids. In this paper, a novel adaptive protection system for microgrids is presented. The protection scheme is based on a protective device that includes two directional elements which are operating in an interleaved manner, namely overcurrent and undervoltage elements. The proposed protection scheme can be implemented in microprocessor-based relays. To define the settings of the protective device, a robust programming approach was proposed considering a finite set of fault scenarios. The scenarios are generated based on the predictions about the available energy and the demand. For each decision step, a robust optimization problem is solved online, which is based on forecasting with a confidence band to represent the uncertainty. The system is tested and compared using real data sets from an existing microgrid in northern Chile. To assess the performance of the proposed protection system, fault scenarios not considered in the optimization were taken into account. The results obtained show that the proposed protective device is able to manage those failure scenarios, as well as those included in the tuning of the settings. Practical considerations are also discussed.

LUT Assisted Adaptive Overcurrent Protection of Reconfigurable Microgrids

Microgrids are the key solution to handle the growing technical, environmental and economical concerns of existing power system networks. The purpose of this paper is to develop an intelligent and adaptive overcurrent protection system for a microgrid. This system is capable of monitoring, protecting and controlling the microgrid. A look up table is created and maintained at the central protection system of the microgrid, which has details of normal and faulted current in all feeders for various topologies of the microgrid system. It has the optimized values for time dial setting and operating time of relays for faults at a specific location in the reconfigured system, which is generated using Dual Simplex algorithm. Hence the Central Protection System aids in providing suitable overcurrent relay coordination to the microgrid, which may incur reduced network disconnection. The hardware prototype of the Central Protection System is realized, tested and validated on a balanced 21-bus microgrid system.

Fuzzy-based Non-communicating Adaptive Overcurrent Relay

Abstract The technological advances of the electrical power system have brought several benefits including more robust and safe operation. Microprocessor-based digital relays may provide important features such as allowing quick and efficient setting according to the network changes. Considering the load variations throughout the day, such function becomes essential to maintain the coordination of the protection system. Adjusting the parameters of an overcurrent protective device manually may introduce non-optimal settings, mostly due to the difficulties in dealing with many possible solutions. This paper shows the modeling of an adaptive protection system based on Fuzzy Logic which parametrizes the pick-up current of inverse-time overcurrent relays by not demanding a centralized processing structure and communication among them. Two variables are taken into account: the pre-fault current and the variation of current. The IEEE 4-bus test system is used in ATP-EMTP program to illustrate the method considering several load, short-circuit and fault resistance values. The results confirms the benefits of smart protection system which adapts automatically according to the changes and has considerable sensitivity for high impedance faults. The proposed method is not dependent of system size.

IEC 61850-based adaptive protection system for the MV distribution smart grid

Abstract The installation of protection systems on the Medium Voltage (MV) network is probably the most pragmatic topic of the smart grid in those contexts where the regulation of distribution systems includes output-based incentives to Distribution System Operators (DSOs) related to the quality of service. One of the main obstacles to the diffusion of such a solution is related to the MV network configuration – e.g. the relation between the feeding primary substation and fed secondary substations – which is altered for various reasons, requiring different settings for the protection devices placed along the network. The present work describes an innovative approach to the dynamic reconfiguration of protection devices used to implement advanced fault location, isolation and service restoration solutions. The proposed solution, realized during the activities of the FP7 European Project IDE4L, has been implemented based on the IEC 61850 standard adoption, in order to assure the interoperability, modularity and scalability of the proposed approach.

Comparison of Programmable Logic and Setting Group Methods for adaptive overcurrent protection in microgrids

Adaptive overcurrent protection systems for microgrids with distributed generators require that overcurrent relays need to be adjusted to different circuit paths and feeder fuses. Adaptive overcurrent protection systems in recent publications were based on the Setting Group method, using the functions resident in the relay. In this paper, the Programmable Logic method was developed for an adaptive overcurrent protection system, using the programmable logic and math operators instead of the functions resident in the relay. The Programmable Logic and Setting Group methods were validated using a real-time simulator with two relays in-the-loop. The selectivity, reliability and speed of the adaptive protection system based on the Programmable Logic and Setting Group (previous work) methods were compared for a microgrid with distributed generators (diesel generators). Similar results were obtained with both methods. However, the Setting Group method limited the number of overcurrent settings by the available setting groups of relays, and disabled the relays for a fixed amount of time, reducing the relay’s availability. On the other side, the Programmable Logic method is recommended because it improves the capacity of relays by using one setting group, and avoids relays to be disabled because switching setting groups is not being necessary. In microgrids that require an adaptive overcurrent protection system for different circuit paths and seasonal (winter and summer) settings, adaptive overcurrent protections based on programming alternative is a better solution. This requires relay engineers to be trained in relays’ programming techniques.

Comparison of non-real-time and real-time simulators with relays in-the-loop for adaptive overcurrent protection

Non-real-time or real-time simulators with relays in-the-loop can be used to test and validate adaptive protection systems. In this paper, the non-real-time and real-time simulator test procedures with relays in-the-loop for an adaptive overcurrent protection system in a microgrid with distributed generators (diesel generators) were described, contrasting the test set-up and experiment preparation. In addition, test results for the non-real-time and real-time simulators with relays in-the-loop were compared. Selectivity, reliability and speed for an adaptive overcurrent protection system was validated using both relays in-the-loop test procedures. Of 44 tripping tests ran for both relays in-the loop techniques, the breakers near the fault tripped and the other breakers remained closed in 34 cases, and backup relays tripped when primary relays did not trip in 10 cases (backup tests). Inverse time overcurrent elements tripped breakers at maximum fault currents in less than 0.5s. To test adaptive overcurrent protection systems, it is recommended to use the relays in-the-loop with real-time simulator instead of non-real-time simulator, to optimize the test validation of primary and backup relays working together.

Treatment of Alzheimer Disease With CT Scans: A Case Report.

Alzheimer disease (AD) primarily affects older adults. This neurodegenerative disorder is the most common cause of dementia and is a leading source of their morbidity and mortality. Patient care costs in the United States are about 200 billion dollars and will more than double by 2040. This case report describes the remarkable improvement in a patient with advanced AD in hospice who received 5 computed tomography scans of the brain, about 40 mGy each, over a period of 3 months. The mechanism appears to be radiation-induced upregulation of the patient’s adaptive protection systems against AD, which partially restored cognition, memory, speech, movement, and appetite.

Adaptive Corrosion Protection System Using Continuous Corrosion Measurement, Parameter Extraction, and Corrective Loop

A simple current-sourced adaptive corrosion protection system (ACPS) along with a technology to extract the protection current from the Tafel plot is presented. For reliable protection of the target metal, first, the Tafel plot of the target metal is obtained. Subsequently, a novel technique proposed in this paper is used to extract the protection current from the Tafel plot. This extracted protection current is fed to the target metal to protect the metal in the existing corrosive environment. This three-part system is adaptively used to update the required protection current to effectively protect the target metal continuously. All these functionalities are integrated in a stand-alone ACPS that effectively diagnoses the corrosion status and updates the protection parameters without any manual interaction or physical modification of the set-up to offer modularity, reliability, and cost saving. To validate the technique, a laboratory scale system is realized and tested using various metal samples and various corrosive mediums. Using the experimental system, A36 metal coupons are effectively protected with protection (inhibition) efficiency of 40–100%in different corrosive mediums that can extend the life expectancy of the target metal from ~2 times to more than 100 times for the tested corrosive mediums.

A novel approach to adaptive active relay protection system in single phase AC coupling Off-Grid systems

This research paper presents an Adaptive Active Relay Protection (AARP) system for the failure state and abnormal operation states, such as short-circuits and overloads, in single phase Off-Grid systems. This proposed AARP system is intended for an Off-Grid system which contains several independent sources of short-circuit power and is able to change and configure itself for various operation states in the Off-Grid system. Moreover, the proposed AARP system is based on central control and real-time analysis of data acquired from electronic measuring devices. Presented paper includes a theoretical analysis and the experimental work is confirmed in practice.

An Adaptive Overcurrent Protection Scheme for Distribution Networks

Distribution networks are evolving toward the vision of smart grids, with increasing penetration of distributed generation (DG), introduction of active network management (ANM), and potentially islanded modes of operation. These changes affect fault levels and fault current paths and have been demonstrated to compromise the correct operation of the overcurrent protection system. This paper presents an adaptive overcurrent protection system which automatically amends the protection settings of all overcurrent relays in response to the impact of DG, ANM, and islanding operation. The scheme has been developed using commercially available protection devices, employs IEC61850-based communications, and has been demonstrated and tested using a hardware-in-the-loop laboratory facility. A systematic comparison of the performance of the proposed adaptive scheme alongside that of a conventional overcurrent scheme is presented. This comparison quantifies the decrease in false operations and the reduction of mean operating time that the adaptive system offers.

Estimating Dynamic Model Parameters for Adaptive Protection and Control in Power System

This paper presents a new approach in estimating important parameters of power system transient stability model such as inertia constant $H$ and direct axis transient reactance $x_{d}^{\prime}$ in real time. It uses a variation of unscented Kalman filter (UKF) on the phasor measurement unit (PMU) data. The accurate estimation of these parameters is very important for assessing the stability and tuning the adaptive protection system on power swing relays. The effectiveness of the method is demonstrated in a simulated data from 16-machine 68-bus system model. The paper also presents the performance comparison between the UKF and EKF method in estimating the parameters. The robustness of method is further validated in the presence of noise that is likely to be in the PMU data in reality.

An Enhanced Adaptive Algorithm to Mitigate Mis-coordination Problem of the Third Zone of Distance Relays

Cascaded tripping of power lines due to mal-operation of zone 3 distance relays is one of the main causes of many blackouts worldwide. The improved protection technique for zone 3 can help to prevent such mal-operation and, thus, more reliable power systems can be envisaged. This paper presents a novel zone-3 setting scheme based on impedance seen by distance relays in order to calculate zone-3 setting of the relays when faults are simulated on the reach of zone-2 of primary distance relays. The new technique is also enhanced to be used in an adaptive protection system. Since three phase fault rarely occurs in the system and in order to have better demonstration of effectiveness of the proposed scheme, it is tested for various type of faults such as, two phase (AB), single phase to ground (AG) and two phase to ground (ABG) as well as three-phase (ABC) using data simulated through DIgSILENT in the IEEE 30-bus test system during different topologies. The simulation results show that the novel zone 3 distance relay elements using the proposed method operate correctly for various events.

К вопросу о применении адаптивных устройств релейной защиты на подстанциях промышленных предприятий

The paper is dedicated to the relevance of the use of adaptive relay protection systems in industrial power supply, in particular in terms of power supply system of large iron and steel works. The characteristics of such objects, distinguishing them from the network power systems are given. The authors had estimated the sensitivity factors the key substations of Magnitogorsk energy hub relay protection, the results of which showed that current distribution in the network and, as a consequence, the size of emergency regimes vary considerably as a result of a change in the operational state of the circuit, leading to a reduction in the sensitivity of relay protection and discrepancy between its EIS requirements. All calculations were performed using the original software developed at the department of industrial power supply of Nosov MSTU.

Zone-3 Impadance Reach Setting of Distance Relays by Including In-feed Current Effects in an Adaptive Scheme

The undesired operation of zone 3 may be one of the most conspicuous protective relay features due to the incorrect zone 3 relay operations which have been conducive to the severity of blackouts. Therefore, determining the accurate zone 3 setting of the distance relay is deemed to be necessary. This paper focuses on the development of a new technique for calculating zone-3 setting of distance relays. The proposed technique utilizes impedance seen by distance relays in order to compute zone-3 setting of the relays when faults are modeled on the reach of zone-2 of primary distance relays for the maximum and minimum generation outputs of the power system. The new technique is also improved to be used in an adaptive protection system. The technique and its adaptive version are applied to the IEEE 30-bus test system under different operating circumstances to reveal its robust performance. System simulation studies show that the proposed scheme is able to increase the reach of zone-3 relays without causing mis-coordination problems. Therefore, the two main requirements of the protection system, namely security (without causing coordination) and simultaneity, would be satisfied.

Adaptive Protection and Microgrid Control Design for Hailuoto Island

Microgrids can provide various economic and environmental benefits but their implementation poses great technical challenges in control, protection and energy management. One of the most important technical aspects in microgrids is distribution system protection. This paper first demonstrates a need for and then focuses on the design aspects of the adaptive protection system addressing issues such as: selection of alternative setting groups, components and system architecture; system configuration and programmed logic. The system is based on a centralized controller running the real-time analysis of the data received from the field Intelligent Electronic Devices and communicating with them by means of IEC 61850 communications. The adaptive protection and microgrid control system has been developed and currently being installed at Hailuoto island in Finland.

Remedy for radiation fear - discard the politicized science.

Seeking a remedy for the radiation fear in Japan, the author re-examined an article on radiation hormesis. It describes the background for this fear and evidence in the first UNSCEAR report of a reduction in leukemia of the Hiroshima survivors in the low dose zone. The data are plotted and dose-response models are drawn. While UNSCEAR suggested the extra leukemia incidence is proportional to radiation dose, the data are consistent with a hormetic J-shape and a threshold at about 100 rem (1 Sv). UNSCEAR data on lifespan reduction of mammals exposed continuously to gamma rays indicate a 2 gray/year threshold. This contradicts the conceptual basis for radiation protection and risk determination established in 1956-58. In this paper, beneficial effects and thresholds for harmful effects are discussed, and the biological mechanism is explained. The key point: the rate of DNA damage (double-strand breaks) caused by background radiation is 1000 times less than the endogenous (spontaneous) rate. It is the effect of radiation on an organism's very powerful adaptive protection systems that determines the dose-response characteristic. Low radiation up-regulates the protection systems, while high radiation impairs these systems. The remedy for radiation fear is to expose and discard the politicized science.