Design and Simulation of Differential Protective Relay (DPR) to 33/11kv Delta-Wye Transformer Using Saber Software Simulator

Substation automation constitutes the integral part of distribution automation. An automated distribution system may require many remote and central intelligent controllers or computers running synchronously in a very large boundary that are capable of making decisions and performing control actions. A protective relay is a device that responds to abnormal conditions in an electrical power system to operate a circuit breaker to disconnect the faulty section of the system with the minimum interruption of supply. Reliability, speed and selectivity are the most desirable characteristics of a protective relay. Numerical relays play an essential role in various distribution automation functions, and instead of mere protection relays it is also able to interact with the other instruments. In most utilities, power transformers often represent the expensive and also the largest capital purchase in the transmission and distribution system. The gas relay or bucholz relays is particularly important since it gives early warning of a slowly developing fault, permitting shutdown and repair before serious damage can occur. For short-circuit condition or internal faults, differential protective relays (DPR) are usually employed. In this project, SABER software simulator was used to implement solid-state digital-type components for the DPR. The project focused on the protection of 33/11 kv delta-wye transformer when internal fault happens. 3 packages solid-state digital-type DPR were designed to protect delta-wye transformer when internal fault happens. There are several problems encountered in this project where in SABER, 1) it is difficult to configure an initial values for delta-wye transformer due to obtain a desired outputs on wye-side, 2) 3-phase generator cannot do any partial changes either leading or lagging power factor, and 3) during circuit breakers switching, very high surges appear which can cause destruction to the power system components. Hence to reduce surges below the allowable maximum value during switching, this can be solve by implementing circuit breakers that not only works as a switch but also as impedance. Circuit breakers impedance can also be assume as an arc extinguisher. By extinguish the arc, the surges also will be reduce. Hence the results of this project are not only to isolate the delta-wye transformer from the generator and as well loads when fault happened, but is also capable to reduce surges during circuit breakers switching

Artificial neural network application in coordination of directional overcurrent protective relays in electrical mesh distribution network

Directional Overcurrent relays (DOCR) applications in meshed distribution network (MDN) eliminate short circuit fault current flow due to the system topological structure. Effective and reliable coordination between primary and secondary relay pairs eliminated miscoordination in MDN system. Otherwise, the risk of safety of lives and installations may be compromised alongside with system instability. This paper proposes an Artificial Neural Network (ANN) approach to improve the optimized DOCR response time to short circuit fault within the MDN in order to address miscoordination problem due to wrong response time among adjacent DOCRs to the same fault location. A test model series of several DOCRs in simulated IEEE 8-bus test system, designed in DigSilent Power Factory. Extracted data from three phase short circuit fault analysis, applied in numerical optimization of time setting multiplier (TSM), plug setting multiplier (PSM) and operation time of DOCRs. These data adapted in function fitting training of ANN to determine an improved optimal operation time of DOCRs in general network

Reliability-based phasor measurement unit with outage of transmission lines

This paper discussed on the Monte-Carlo simulation technique to determine the optimal placement of Phasor Measurement Unit (PMU) in power system whilst ensuring the observability of the system. In addition, the information on Force Outage Rate (FOR) of the system can be calculated using Markov Chain technique. The FOR represents the level of risk security for the transmission line that happened because of unscheduled and unexpected failure or repair in the system. Subsequently, the reliability model of the transmission line can be developed. Using IEEE 57-bus system, the results obtained from Monte-Carlo simulation technique demonstrate the optimal PMU placement, the desired reliability of the Wide Area Monitoring System (WAMS) as well as the number and location of covered contingencies of the system

Reliability assessment by sensitivity analysis due to electrical power sequential tripping for energy sustainability

A drastic change has occurred over the last few years in the electrical power business, where a significant worldwide revolution has taken place and changing the design of electrical powers. It has become imperative for the utility to handle the electrical power reliably as poor performance can lead to electrical power outages which will inevitably have an adverse impact on a nation’s economy and society. Hence, the power company should consider devising suitable pre-emptive measures to avoid the possibility of electricity supply disruptions. These disruptions may have a potentially catastrophic effect on the running of the system, which may even include consumers having to bear monetary costs. This research looks at the valuations of risk and reliability cost/worth-based customer interruption cost due to static system sequential tripping. The performance of the suggested techniques are evaluated through comparing risk-based valuations and reliability cost/worth valuations corresponding to the transfer capability results which are correlated to the static system sequential tripping. The results have demonstrated that the unpredictable sequential tripping must not be ignored from the transmission reliability margin determination. Hence, the proposed techniques are likely to play an important role for energy sustainability of the future

Hybrid signal processing and machine learning algorithm for adaptive fault classification of wind farm integrated transmision line protection

The technological advancement in integration of Renewable Green Energy Sources (RGES) like Wind Farm Generators (WFG), and Photovoltaic (PV) system into conventional power system as a future solution to meet the increase in global energy demands in order to reduce the cost of power generation, and improve on the climate change impact. This innovation also introduces challenges in the power system protection by it being compromised due to injected fault current infeeds on existing facilities. These infeed leadto the undesired trip of a healthy section of the line, and protection system failure. This paper presents a soft computational approach to adaptive fault classification model on High VoltageTransmission Line (HVTL) with and without RGES-WFG integration topologies, using extracted one-cycle fault signature of voltage and current signals with wavelet statistical approach in Matlab. The results are unique signatures across all fault types and fault distances with distinct entropy energy values on proposed network architecture. The supervised machine learning algorithm from Bayesian network classified 99.15 % faults correctly with the operation time of 0.01 s to produced best-generalized model with an RMS error value of 0.05 for single line-to-ground (SLG) fault identification and classification. Best suitable for adaptive unit protection scheme integration

A New Algorithm for the Available Transfer Capability Determination

This paper presents a fast and accurate method to determine the available transfer capability. Ralston's method is used to predict the two trajectory points of voltage magnitude, power flow, and maximum generator rotor angle difference. Then, the cubic spline interpolation technique is used to accurately trace the P-V, P-S, or P- Δ curves between two points of trajectory. The P-V, P-S and P- Δ curves represent as the variations of voltage magnitude, power, flow and maximum generator rotor angle difference due to the increase of power transfer. The actual available transfer capability value is determined at the intersection point between the curve and the constraints limit. The effectiveness of the proposed method is verified by referring to the results of ATC for a case study of 2737-Polish system and 39-New England bus system. The proposed method gives satisfactorily accurate and fast computation of ATC as compared to recursive AC power flow method

Integrated monte carlo-evolutionary programming technique for distributed generation studies in distribution system

This paper presents the optimal multiple distributed generations (MDGs) installation for improving the voltage profile and minimizing power losses of distribution system using the integrated monte-carlo evolutionary programming (EP). EP was used as the optimization technique while monte carlo simulation is used to find the random number of locations of MDGs. This involved the testing of the proposed technique on IEEE 69-bus distribution test system. It is found that the proposed approach successfully solved the MDGs installation problem by reducing the power losses and improving the minimum voltage of the distribution system

Modeling and evaluating the customer interruption cost due to dynamic electrical power and energy failure

Sequence of failures that aggravates catastrophic events of a power system has attracted a great number of researchers’ attention in exploring and analyzing its enormous losses to the society and economy of a country. Power system cascading collapse is an event in which failure of an electrical component such as transmission line or generator leads to sequence of failures in other equipment. This catastrophic event could lead to major electrical energy failure. Therefore, it is imperative to study the effect of power system cascading collapse in assessing reliability cost/worth. This research introduces the assessments of risk and reliability cost/worth-based Customer Interruption Cost (CIC) in relation to dynamic system cascading collapse. The results obtained from the analysis performed have proven that a large cost of CIC is resulted due to dynamic electrical energy failure. This connotes that uncertain disconnection of the exposed transmission lines together with the exposed generator which occurred in the power system failure, ultimately will impose a significant impact on the customer interruption cost. On top of that, the results of customer interruption cost also have proven that the uncertainty of dynamic power electrical power and energy failure should not be neglected. Therefore, the proposed technique is reliable and confers promising results in determining risk and reliability cost/worth of the system

A Heuristic Ranking Approach on Capacity Benefit Margin Determination Using Pareto-Based Evolutionary Programming Technique

This paper introduces a novel multiobjective approach for capacity benefit margin (CBM) assessment taking into account tie-line reliability of interconnected systems. CBM is the imperative information utilized as a reference by the load-serving entities (LSE) to estimate a certain margin of transfer capability so that a reliable access to generation through interconnected system could be attained. A new Pareto-based evolutionary programming (EP) technique is used to perform a simultaneous determination of CBM for all areas of the interconnected system. The selection of CBM at the Pareto optimal front is proposed to be performed by referring to a heuristic ranking index that takes into account system loss of load expectation (LOLE) in various conditions. Eventually, the power transfer based available transfer capability (ATC) is determined by considering the firm and nonfirm transfers of CBM. A comprehensive set of numerical studies are conducted on the modified IEEE-RTS79 and the performance of the proposed method is numerically investigated in detail. The main advantage of the proposed technique is in terms of flexibility offered to an independent system operator in selecting an appropriate solution of CBM simultaneously for all areas