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This paper presents a new grid connected induction generator system having open-end stator windings with a series compensator (voltage source inverter (VSI) connected in series) for reactive power compensation. The proposed scheme consists of a two-level capacitor fed voltage source inverter connected to one side of the windings of the induction generator while the other end of the windings are connected to the grid. A current oriented control scheme is developed to control the operation of the VSI to ensure that it compensates the reactive power required by the induction generator. Thus the induction generator system can supply active power to the grid without drawing reactive power from it for excitation. Unlike the shunt compensated induction generator systems, the proposed scheme does not require an interfacing inductor for connecting to the grid thereby reducing the hardware footprint. The proposed scheme is validated by simulation using PLECS software and the simulation results are presented in the paper.

Publisher Copyright: © 2023 The Authors. Energy Science & Engineering published by Society of Chemical Industry and John Wiley & Sons Ltd. As the load on distribution networks grows, system operators and planners are constantly challenged with the issue of voltage regulation or enhancing the quality of supply to customers at the load end of lengthy distribution lines. This paper presents the optimum determination of series capacitor units in a distribution system to maximize energy-saving and enhance voltage levels. Interestingly, series capacitors can enhance the capability of transmission lines, reduce line losses, enhance the performance of buses with large induction motor loads and reduce voltage flicker. At the same time, the limitations of series compensation are taken into consideration while calculating its optimum values. To achieve the planning objective and optimal load flow objective, two strategies: The Improved Grey Wolf Optimization method (I-GWO) and Tabu Search (TS), are hybridized to get the benefit of their advantages. The I-GWO has a movement strategy called dimension learning-based hunting for enhancing the balance between global and local search and maintaining diversity. The proposed (I-GWO-TS) algorithm can solve mixed-integer programming to achieve the planning and the optimal load flow objectives. The proposed method can be applied to a real Egyptian distribution system that is heavily loaded, with poor voltage regulation, and also has high-power losses. The obtained results demonstrate the capability of the proposed approach to determine optimal series capacitors’ location and sizing for maximization of energy saving. Further, the proposed method improves the network performance regarding the voltage profile and power losses, although the limitations of including series compensation were considered in the distribution system.

Protection engineers and academicians are continuously working towards better relaying for modern transmission structures. This has become a requirement because transmission structure, nowadays, is...

When wind energy conversion systems (WECS) are integrated with the Grid system then there are power quality issues arises. The fluctuation in the wind power delivery to the grid demands robust control for a better power quality. Therefore, voltage and frequency stability due to integration of wind to the grid is the primary concern to improve the overall grid integration capability for WECS. This paper reviews the power quality issues in the power grid due to introduction of WECS. The WECS integration with the grid introduces dynamic issues that include sub-synchronous resonance (SSR), low voltage ride through (LVRT), frequency support from wind generation, synchronization, and transients. Also, it focusses on the sub synchronous resonance introduced due to introduction of doubly-fed induction generator (DFIG) wind turbines to the transmission lines with capacitive seriescompensation. The review of various power quality issues and methods used by the researcher’s mitigations are discussed and detailed further research perspective.

Currently there is a need to synchronize operation of the electric power system in the remote areas and increase of existing lines transmission capacity. The construction of new power transmission lines involves high economic expenditures. Well-known papers consider the issues of application of controlled series compensation devices only for long-distance power transmission lines with voltage of 500 kV and higher to increase the transmission capacity and the level of stability. The aim of the study is to increase the stability and the limit of the transmitted power when controlled series compensation devices are installed on 220 kV lines. It is necessary to develop a criterion of aperiodic steady-state stability of an electric power system with a 220 kV-controlled power transmission line. Methods of mathematical modeling of electric power system, the theory of long-distance power transmission lines and electromechanical transients, and methods of analyzing electric power system stability were used. A.M. Lyapunov’s first approximation method was used to develop a simplified mathematical model. We applied the developed software as a simulation tool. An analysis was carried out to study the influence of series compensation devices regulation coefficients on the aperiodic steady-state stability of the electric power system and the transmission capacity of 220 kV power transmission lines. A change in the modulus of voltage drop at the power transmission and the angle characteristics under the influence of the regulation coefficients of the series compensation device was revealed. A criterion of aperiodic steady-state stability has been developed for systems of this kind with controlled series compensation. It differs from traditional ones by considering the changes in the voltage drop in the power transmission and it allows more accurate estimation of the proximity to the stability threshold. An assessment of aperiodic steady-state stability according to the formulated criterion for an electric power system with a controlled series compensation device on a 220 kV line was obtained. The values of the control coefficients of the series compensation device have been determined. No violation of the steady-state stability occurs under the given values. The results can be used to solve the issues of increasing the transmission capacity of transmission lines to improve the stability of the system.

This paper deals with the design of SPM vernier machine with high slots/pole/phase q, to get higher torque density as well as improved power factor by applying the concept of series compensation. The torque density of a vernier machine can be enhanced by increasing the number of slots/pole/phase q, but as q increases the drastic increase in the reactance makes the power factor even worse. Therefore, it is general to choose low q, even if higher torque can be obtained with higher q. In this study, the idea of series compensation is applied to get vernier machine with high q without the low power factor problem. Series compensation is performed by supplying the desired reactive power to the machine from an additional inverter with a floating capacitor. To validate the theoretical analyses, three SPM vernier machines with different q (1 ∼ 3) are designed and then analyzed by using FEM.

The appearance of flexible AC Transmission System (FACTs) controllers Is completely changing the way transmission systems are controlled and operated. Most facts controllers are basically based on variable shunt and/Qr series compensation of transmission systems. One of the most famous type of FACTs Is the Static VAr Compensator to r (SVC), which is basically used liS It ture for both voltage and voltage stability problems. However, SYC may also affects the Available Transfer Capability of the system (ATC), line Overload and losses. As the power system is economical1y operated, hence it is important to study the. economical effects of SVC on power system opera lion . This paper presents a construction of II complete Cost Benefit Analysis (CBA) model (or SVC insertion into power system 10 select the best location and size for that insertion . Generally CBA is based on comparison between the cost and benefit for a specific alternative. In our case, the cost components are mainly the cost of the SVC device and its cost of installation anti maintenance. While the benefit components are that due to Improving voltage stability in terms of increasing the voltage stability margin (VSM), benefits due to extending the ATC, and the benefits as a result of n:iievillg line overloads in the system in terms of reducing the line overload (LO) and finally reducing the system losses. However for the same hardware the coast is the same. So, the. most economical alternative is the one with the maximum total benefit. This paper also, introduces a new Unified Index (UI) (or ranking contingencies Tile proposed C DA algorithm is tested for SVC in5ertion into the I EEE 26-bus system subject to contingencies.

The paper proposes an analytical approach to evaluate the effects of series compensation of an overhead transmission line (OHL) concerning the increase of (1) loadability and (2) practical loading of the line. The first part of the paper focuses only on the line characteristics, and proposes an analytical approach to determine the loadability curves of the line as a function of the compensating capacitive reactance. In the second part of the paper, the perspective shifts to examine the power loading of the selected OHL in a meshed electrical network. The target is to evaluate the compensation degree required to achieve a desired power flow increase in the line. To this purpose a fast analytical method, based on the compensation theorem, is presented. Preserving the linearity of the network model, the proposed method allows computation of the needed compensation degree by means of a closed form equation. Numerical applications performed on two simple test networks allow to compare the method with an ad hoc implemented classical optimal power flow. The results validate the method and highlight its effectiveness as a simple and useful tool to support power system planners and designers.

This study introduces a fault location technique for three-terminal series-compensated untransposed parallel transmission lines utilizing the three terminals’ synchronized data. The proposed techni...

—Subsynchronous resonance (SSR) is an undesirable phenomenon in series compensated power system which tries to menace the stability of both electrical and mechanical system. This paper researches t...

To respond to the ever-increasing power demand of load centers, power is transmitted at extrahigh voltages. However, an increase in power transfer level should be supported by an enhanced level of security. Flexible AC Transmission System (FACTS) devices present an economical and efficient alternative to consider for achieving higher power transfer level with enhanced security instead of introducing new transmission facilities, to maintain a large stability margin of power in transmission line. This project aims to optimize the level of series compensation in transmission networks using Artificial Neural Network (ANN). Series compensation enables higher level of power to be transferred by reducing (reactive) losses. Among the series FACTS controllers, Thyristor Controlled Series Compensator (TCSC) has been chosen to be optimized on an SMIB system. Lead-Lag (LL) based TCSC remain the controller of choice due to the favorable performance to cost ratio. Nevertheless, modeling the highly non-linear power system with a linear controller, limits the system’s performance during adversities. ANN being non-linear per se and possessing high generalization capabilities, offers more versatility in modeling the power system. Indeed, an ANN based TCSC was designed and the performance during contingencies was compared to that of the LL based TCSC. As expected, the ANN based TCSC demonstrated a damping capability twice as fast and offering the SMIB system with a higher robustness as well as better resistance to fault condition. To increase the accuracy and reliability of the proposed controller, the investigation can be performed on a multi-machine system with different loading conditions as well as determining the optimal location of the TCSC module.

Enhancement the performance of electrical power system network became essential forincreasing the realiability of power transmission during any disturbance and variations. Oneof these variations is series compensation in heavily loaded transmission lines which affectsdirectly the Distance Relay (DR) settings. This paper provides control system architecture tocover the setting and coordination of protection scheme based on DIgSILENT power factoryprogram with practical representation of interactive control system by using SIMATICmanger, and WinCC programs. Applied scheme makes protection system more reliable withoptimal tripping time. يعتبر تحسين نظام الوقاية من أحد أهم النقاط الأساسية وذلک لزيادة موثوقية أنظمة القوى الکهربية نتيجة للتغيرات الناتجة عن ظروف التشغيل. وأحد هذه التغيرات تغير قيم تعويض المکثفات بالخطوط التي بها تعويض على التوالي والتي تؤثر تباعا على قيم الضبط الخاصة بمرحل الوقاية المسافية، فإن هذا العمل البحثي يسعى إلى تطبيق تکامل بين نظام الوقاية ونظام تحکم آلي مرکزي للقيام بتحسين أداء مرحل الوقاية المسافية لجعل نظام الوقاية أکثر إعتمادية وموثوقية

To improve transmission capacity and stability margin of the power system, the doubly fed induction generators (DFIGs) based wind farm is transmitted over lines equipped with series compensation (fixed capacitors). However, the utilisation of series compensation brings the potential risk of subsynchronous resonance (SSR) in the power system. In this study, the SSR issue in DFIGs based wind farm integrated to a series-compensated network is studied based on the eigenvalue analysis and equivalent impedance model. The linearised state-space model of DFIGs based wind farm integrated to a series-compensated network is built first. Participation factors, sensitivities of eigenvalues and root loci, obtained by linearised state-space model, are observed to investigate the mechanism and the key parameters of SSR. Then, a method that can mitigate SSR in DFIGs based wind farm integrated to a series-compensated network is proposed based on virtual series resistance of the rotor. At last, the eigenvalue analysis and simulation are conducted to verify the effectiveness of the proposed mitigation method.

Subsynchronous oscillations (SSO) were an issue that occurred in the past with conventional generators and were studied extensively throughout the years. However, with the rise of inverter-based resources, a new form of SSO emerged under the name subsynchronous control interaction (SSCI). More specifically, a resonance case occurs between Type-3 wind turbines and series compensation that can damage equipment within the wind farm and disrupt power generation. This work explores the types of SSCI and the various analysis methods as well as mitigation of SSCI. The work expands on the concept of frequency scan to be able to use it in an on-line setting with its output data used to mitigate SSCI through the modification of wind turbine parameters. Multiple frequency scans are conducted using PSCAD/EMTDC software to build a lookup table and harmonic injection is used in a parallel configuration to obtain the impedance of the system. Once the impedance of the system is obtained then the value of the parameters is adjusted using the look-up table. Harmonic injection is optimized through phase shifts to ensure minimal disruption of the steady-state operating point and is conducted using Python programming language with PSCAD Automation Library. Simulation results demonstrate the effectiveness of this approach by ensuring oscillations do not grow exponentially in comparison to the regular operation of the wind farm. Master of Science Due to climate change concern and the depletion of fossil fuel resources, electrical power generation is shifting towards renewables such as solar and wind energy. Wind energy can be obtained using wind turbines that transform wind energy into electrical energy, these wind turbines come in four different types. Type-3 wind turbines are the most commonly used in the industry which use a special configuration of the classical induction generator. These wind turbines are typically installed in a distant location which makes it more difficult to transfer energy from its location to populated areas, hence, series capacitors can be used to increase the amount of transferred energy. However, these series capacitors can create a phenomenon called subsynchronous control interaction (SSCI) with Type-3 wind turbines. In this phenomenon, energy is exchanged back and forth between the series capacitors and the wind turbines causing the current to grow exponentially which leads to interruptions in service and damage to major equipments within the wind turbine. This work explores SSCI, the tools to study it, and the currently available mitigation methods. It also presents a method to identify the cases where SSCI can happen and mitigates it using adjustable parameters.

With the rapid development of new energy, the problem of power oscillation caused by large-scale wind farm access system has become increasingly prominent, such as the subsynchronous resonance between doubly-fed induction generator (DFIG) and fixed series compensation, which threatening the security and stability of the system seriously. Since there may not be a single type of wind turbine in the same wind farm, this paper aims to clarify whether there is interaction between different types of wind turbines in the wind farm, thus focuses on the subsynchronous oscillation (SSO) of a system that including DFIG based wind farm, direct-drive permanent magnet synchronous generator (PMSG) based wind farm and fixed series compensation. A linearization model of hybrid-based wind farm is established to analyze the influence of wind farm proportion, control parameters on the operation stability of the system. Based on the dynamic impedance model of hybrid-based wind farm, the mechanism of SSO is further revealed. A time-domain simulation model is built in EMTDC / PSCAD to verify the correctness and effectiveness of the theoretical analysis.

Deep decarbonization is the goal of modern power systems, so it is inevitable that large-scale wind farms will be integrated into systems. This also gives rise to many problems, which have been studied in detail in the literature. However, these studies basically have two deficiencies. One is to assume that traditional generator units are fully loaded, and the other is not to compare the differences in the impact of different types of wind farm. This paper discusses these two points in detail. Taking a series-compensated transmission system as the research object, and assuming that the wind farm only replaces part of the power of the traditional generator unit in the transition period of energy conversion, the difference between the torsional vibration behaviors of the traditional unit caused by adopting different types of wind farm is discussed. The results of the study show that the impact of integration of the type 3 wind farm is dominated by the induction generator effect of doubly fed induction generator units. The penetration rate as low as 19% could cause instability. However, the paralleled metal-oxide varistor can effectively improve the stability. For the type 4 wind farm, the dominant factor turns out to be the de-rating operations of the steam turbine generator unit. The allowable penetration rate depends on the turbine damping. When the turbine damping is sufficient, the penetration rate can be as high as 87.5%. In conclusion, in order to integrate wind farms into a series compensated transmission system, one should not only focus on the compensation factor to avoid the sub-synchronous torsional vibrations, but also pay attention to the types of wind farm as well as the penetration rate. The findings can be used as the decision-making basis for the integration of wind farms during the energy transition period.

There is a need to fulfill the electric power demand, and therefore, this chapter presents a discussion on various techniques available to do so including different FACTS devices, for example, TCSC, SVC, and STATCOM. A discussion on DG integration to the distribution system is also included.

Along with the development of extra-high voltage (EHV) and ultra-high voltage transmission (UHV) systems, series compensations (SCs) have attracted more and more attentions. Overvoltage protection performances of SCs are critical to the safety of SCs and project investments. Within the framework of system fault sequences and duty cycles of SCs, a series of external faults simulations are conducted. The setting values of MOV current protection and MOV energy protection are then determined accordingly. Moreover, comprehensive internal faults simulations are also performed to propose reasonable MOV energy. A test system of 500 kV with nine sets of SCs has been built, and the validity of the methodology proposed in this work has been confirmed by case studies.

Dynamic wireless power transfer can reduce the battery capacity of charged devices. This paper proposes a dynamic capacitive power transfer (CPT) system with a compact receiver structure and a reduced transmitter cost. Compared with the conventional solution, the specially designed coupler can reduce the transmitter copper usage by 50% while still achieving stable output. A series compensation with a compensating inductor is adopted on the transmitter side and there is no compensation on the receiver side to minimize the element count and size, especially on the receiver side. Design procedures of the coupler and the compensation network are provided. The mathematical model of the dynamic CPT system is established. Simulation results have verified the effectiveness of the proposed method.

The predominant reason for adding series capacitors in power systems is to increase power transfer capacity enhancing both the voltage and angle stability margins. The resulting decrease in series reactance can determine also undesired effects during faults: the fault current increases in dependence of the compensation degree and of the fault location in the system. This paper investigates the case of an Italian 230 kV – 50 Hz backbone spanning the Centre North – Centre South section, for which re-equipment with high-temperature conductors in conjunction with the installation of 60% capacitive series compensation are being evaluated. The impact of series compensation on faults levels (both phase-to-phase and phase-to-ground) and on the earth fault factors is systematically studied, within the backbone and in the nearby area. A parametric analysis is carried out, considering different generation, load and network scenarios evidencing the impact of series compensation is compatible with present equipment and system operation.

Emerging subsynchronous oscillation (SSO) issues in grid-connected wind farms have gained serious attention after several incidents occurred in the US and China. The temporal and spatial variation of wind speed, the diversified converter control structures, and the continuously varying number of in-service wind turbine generators (WTGs) greatly affect the equivalent impedance reflected by the wind farms. Such frequency-dependent equivalent impedance, as indicated by both theoretical analyses and practical experiences, has a huge impact on the mechanism and characteristics of SSO. In this regard, WTGs contribute to a more complicated type of SSO than those in conventional turbo-generators (CTGs). For instance, SSO in practical wind power systems can be triggered without the participation of series compensation in the transmission network. The emerging SSO phenomena observed in practical WTGs are relatively new, and cannot be properly interpreted by existing literature. This work will first review the historical development of SSO definitions and classification by IEEE, followed by discussions on recent incidents in practical wind farms due to the emerging SSO. Subsequently, new terminologies and classification of SSO are proposed with the aim to better understand SSO in large-scale wind integrated power systems. This paper offers a practical insight and a future perspective for the reader to properly deal with SSO associated with wind power systems.

ObjectivesThe aim of the study is to increase the energy efficiency of an arc furnace’s power supply system and low-voltage circuit. According to the aim of the research, the relevant tasks of determining the capacitor capacity for reactive power compensation and selecting a rational location for its installation are posed.MethodsWithin the framework of the previously developed concept of changing the parameters of the switching transformer in the series compensation circuit, issues of efficient use and consumption of electrical energy by a high power linear load under sinusoidal mode are considered. The installation of static compensators using a direct compensation method with automatic control including 12 stages of regulation is proposed as a means of increasing the efficiency of the arc furnace. Challenges involved in increasing the efficiency of electric power supply to alternating current arc furnaces using compensating reactive power in a low-voltage circuit are considered.ResultsThe viability of using the series compensation circuit of reactive power with the switching of capacitors in the winding of the higher voltage of the series switching transformer is demonstrated.ConclusionIt is shown that for efficient use and consumption of electric energy by highpower linear load under sinusoidal conditions, it is advisable to apply the series compensation of reactive power with the switching of capacitors in the winding of the higher voltage of the series switching transformer. This makes it possible to increase the efficiency coefficient of electric arc furnace power supply devices by reducing the power losses in the power supply system and in the furnace lowvoltage circuit by 1.6 times, as well as reducing the total load in the power transformer by 1.36 times.

TL (Transmission Line) congestion is a key factor that affects the power system operational cost. In addition of renewable generation in National Grid of Pakistan, transmission line congestion are frequent. Consequently, the network in this particular region faces severe congestion and dynamic stability problems. It has been planned that renewable plants shaved to curtail some available generation to minimize this inevitable congestion. However, one of the cost-efficient solutions to this problem is series compensation of lines using TCSC (Thyristor Controlled Series Compensation). It significantly increases the transfer capability of existing power transmission and enhances the dynamic stability of system at a lower cost, and has shorter installation time as compared to the construction of new TLs. This paper deals with the dynamic modeling of a TCSC in the NTDC (National Transmission and Dispatch Company) network with its applications to alleviate congestion during fault conditions. This study has been carried out using simulation software PSS/E (Power System Simulator for Engineers) which does not have a predefined dynamic model for TCSC, this leads to the necessity of creating a user defined model. The model of TCSC has been programmed in FORTRAN and compiled along with existing dynamic models of network components. The results indicate that power flow and dynamic stability of network is enhanced

This study demonstrates the capability and performance of the developed state-of-the-art hardware-in-the-loop (HIL) testing platform based on the real-time digital simulator (RTDS). The evaluations of (i) the effects of thyristor-controlled series compensation (TCSC) on the feeder protection first main (unit protection) and (ii) the performance of feeder protection second main (distance protection) of multi-ended transmission circuits with adjacent TCSC are carried out. Realistic parameters of transmission lines and TCSC are used for system modelling, and practical physical relays are used for the testing. The potential impacts of TCSC on both unit protection and distance protection are analysed based on the simulation results and relay measurements from the developed RTDS-based HIL testing platform.

A dynamic voltage restorer (DVR) can be installed in a middle-voltage (MV) power grid, to concurrently protect a cluster of sensitive loads from voltage sags. To further improve its efficiency and ...

To avoid the under/over-reaching problems of distance protection of extra high voltage/ultra high voltage transmission lines (TLs) in the presence of series compensation, pilot relaying scheme can ...

This paper proposes a novel damping controller for subsynchronous resonance (SSR) mitigation using existing 11-kV variable frequency drive interfaced auxiliary power plant loads. The input of the proposed auxiliary damping controller is the turbine output power $(P_{t})$ . This is a standard signal that is monitored in power plant control rooms and is available locally without the need for additional measurement and/or communication infrastructure. The auxiliary damping controller (ADC) adds an auxiliary speed signal to the existing speed reference in the closed-loop motor drive control in response to any torsional range oscillations seen in $P_{t}$ , via a feedback compensator. The ADC extracts damping by exploiting SSR load interactions and is tuned using a residue-based pole placement technique. The ADC performance is evaluated for both torsional interaction and torque amplification types of SSR in the IEEE First Benchmark and IEEE 68-bus networks. The results show that the ADC is effective in providing positive damping to mitigate unstable SSR oscillations under a range of operating conditions. The proposed solution is a simple yet effective means of providing local control of SSR with minimal additional cost.

The rise in power electronic devices in power system has increased the problems of harmonics and power quality. In this paper I have discussed about the harmonics that are developed in power system due to non-linear loads. The damage of harmonics may rise from normal level to high level depending on their duration and the order of harmonic .So to mitigate this harmonics in power system I have introduced shunt active power filter by series compensation method. In this paper it is discussed how harmonics are reduced using shunt active power filter and it is shown through MATLAB/Simulink .The results of the simulation have been shown where the harmonics developed in power supply has reduced.

Improvement in the power transfer capability and the system stability of long transmission lines by series compensation is a cost-effective solution. However, the Subsynchronous Resonance (SSR) due to series compensation leads to severe risk of Torsional Interactions (TI). This paper presents, a review on damping of torsional interactions using Voltage Source Converter (VSC) based FACTS with various Subsynchronous Damping Controllers (SSDC) proposed in the literature. This review can help researchers to make a comparative study of the impact of FACTS devices and various subsynchronous damping controllers on damping of subsynchronous oscillations.

Power systems are at risk of sub-synchronous oscillation (SSO) when connecting doubly-fed induction generator (DFIG)-based wind turbines to transmission lines with series compensation. This paper focuses on the mechanism and mitigation strategy of SSO. Firstly, the mechanism of SSO is studied from two aspects: induction generator effect (IGE) and sub-synchronous control interaction (SSCI). An equivalent circuit is developed to illustrate the negative resistance effect. Based on the result of the analysis, the SSO mitigation strategy using notch filter and virtual resistance control is proposed. In order to verify the result of analysis and the effectiveness of mitigation strategy, time-domain simulations are carried out based on PowerFactory DIgSILENT.

The application of hybrid reactive power compensation (HRPC) in ultra-high-voltage substations has a nonnegligible impact on the characteristics of transient ground potential rise (TGPR) in the gas-insulated switchgear (GIS) enclosure. In this paper, according to the principle of series compensation and stepped controlled shunt reactors under a very fast transient overvoltage, a simplified model of an HRPC device is established. Based on the generation mechanism of TGPR and the theory of transmission lines, the equivalent simulation circuit of GIS in a substation is designed under the occurrence of TGPR. Simulation experiments comparing the characteristics of TGPR with and without HRPC are conducted to explore the factors that influence TGPR. This paper proposes specific methods of reducing TGPR, and provides a theoretical basis for the construction of GIS protection devices for ultra-high-voltage substations.

FACTS controllers incorporating energy storage device has the ability to operate in all the four quadrants and thereby increases the operational flexibility. In this work, the influence of SSSC supported by Energy Storage (SSSC-ES) on subsynchronous resonance (SSR), in a system provided with fixed series compensation is studied. Effect of SSSC-ES injecting constant real and reactive voltage into the network is analyzed. The sample system is adapted from IEEE FBM and the SSR analysis is carried out using bifurcation technique. Validation of results is done using eigenvalue and transient analysis.

The high compensation degree series compensation has a broad development prospects in long distance and large-capacity UHV transmission lines. But it is generating secondary arc current contains low frequency components with high amplitude when the single-phase grounding fault occurs in the series compensated transmission line, which is not conducive to rapid arc extinguishing. To solve this problem, this paper based on the mechanism of generating secondary arc by series compensation transmission lines, and using ATP – EMTP electromagnetic transient program to establish the simulation model of UHV series compensation device. And the suppression effects of small resistance short connection fault series compensation and linkage bypass series compensation measures on secondary arc current and recovery voltage under different series compensation layout mode are studied respectively. The results show that the attenuation speed of the secondary arc current is related to the series compensation arrangement modes and the time when the series compensation device is short connected or bypassed. Series compensation device short connected or bypassed before circuit breaker tripping which can accelerate the arc extinction speed, and the suppression effect is better when the series compensated double platform segmentation layout is distributed on both sides of the line. The results can be used as a reference for the engineering design of UHV with large capacity and long distance and high compensation series compensation transmission lines.

PV and QV curves are signatures of power system operation under different operating conditions and give an important information about the loading of the system and voltage stability. The series and shunt compensation can be utilized to enhance the voltage and flow in the network. In this paper, PV-QV curves have been obtained for a 5-bus test system and are also obtained for IEEE 9-bus system. The impact of the series and shunt and combined series and shunt compensation was simulated and results are compared. The simulation of the system was carried out in Power World simulator. The margin enhancement has been obtained.

The use of compensation networks increases the power transfer capability of inductive power transfer (IPT) systems in the battery charging process of electric vehicles (EVs). Among the proposed topologies, the Series-Series (SS) and the LCC networks are currently in widespread use in wireless battery chargers based on IPT systems. This paper focuses on the study of the behavior of both compensation topologies when they are detuned due to the tolerances of their components. To compare their performances, a Monte-Carlo analysis was carried out using Simulink and MATLAB. The tolerance values, assigned independently to each component, fall within a [ &minus, 20 , 20] % range according to a normal distribution. Histograms and scatter plots were used for comparison purposes. The analysis reveals that the LCC network allows a tighter control over the currents that flow through the magnetic coupler coils. Moreover, it was found that the increments in those currents can be limited to some extent by selecting capacitors featuring low tolerance values in the LCC compensation. Nevertheless, the SS network remains an appropriate choice if size and cost are essential constraints in a given design.

Finding an optimal location for series compensation is a relevant concern in real electrical networks. This problem is more complex with modern Distributed Series Compensation (DSC). A decision-support methodology for allocating these devices for improving operation and power flow control in high-voltage transmission networks is proposed in this article.

Series capacitors are used in transmission lines for enhancing power transmission limit. However, they complicate the line’s protection due to impedance change of the line, voltage inversion, current inversion and sub-synchronous oscillation. Distance and differential protections are used in different arrangements in transmission line protection. Often they are used together as main and backup protection. In this paper, the fault tree method is used to compare the reliability of three common transmission line protection schemes. The schemes considered here are distance (main)-distance (backup)(Z; Z), differential (main)-distance (backup) (delta;Z) and differential (main)-differential (backup) (delta;delta). Fault trees are used to calculate the reliability of protection schemes in terms of both unavailability and failure rate. The analyses show that, for series compensated lines, using distance protection reduces protection system reliability. Differential protection performs best in terms of reliability despite depending entirely on communication. QC 20191211 FPS12, SweGRIDS

In this paper, the battery energy storage supplementary damping control is introduced to suppress the subsynchronous oscillation of DFIG-based wind farm interfaced with series compensation. Firstly, the conventional control strategy of battery energy storage system is analyzed, and the small signal model of doubly-fed wind farm with battery energy storage is established. Then the eigenvalue method is used to analyze the subsynchronous oscillation mode and related participation factors. Based on the above analysis, the supplementary damping control strategy of battery energy storage is designed to suppress the subsynchronous oscillation of DFIG-based wind farm interfaced with series compensation. Finally, the PSCAD electromagnetic transient simulation model is established. The time domain simulation method is used to verify the effectiveness of the proposed control strategy.

Series capacitors are used in some transmission lines to raise the power transfer limit. If a fault occurs at a location behind which the total reactance is capacitive, the result is current inversion, also known as current reversal. In a current inversion, current leads the voltage instead of lagging it. The probability of current inversion increases with higher levels of compensation. In this paper, the effect of current inversion is studied in distance and differential protection of transmission lines. A 500 kV transmission line is modelled, with compensation levels of 70%, 100% and 140%. Phase to ground faults are applied with fault inception angles of 0, 60 and 90. It is shown that current inversion can cause serious problems with distance protection. Differential protection is not severely affected by current inversion. The protection schemes are significantly influenced by parameters of the capacitor bank overvoltage protection components, particularly the metal-oxide varistor. Part of ISBN 979-835033199-8QC 20191209 FPS12, SweGRIDS

This paper analyzes the requirements of the high-voltage platform measuring system of the series compensation system. Through the analysis of the platform of series compensation system, this paper study’s the noise source and route of TA measuring system on the platform and puts forward a centralized TA measuring system. The system uses signal processing and photoelectric conversion module based on low-power CPLD and reliable redundant power supply. The module features in centralized TA measuring system are also introduced. The system was successfully applied in the Canadian series compensation project.