Nasser Hosseinzadeh

Load Frequency Control of a Multi-Area Power System: An Adaptive Fuzzy Logic Approach

In this paper, a new load frequency control (LFC) for multi-area power systems is developed based on the direct-indirect adaptive fuzzy control technique. LFCs for each area are designed based on availability of frequency deviation of each area and tie-line power deviation between areas. The fuzzy logic system approximation capabilities are exploited to develop suitable adaptive control law and parameter update algorithms for unknown interconnected LFC areas. An H∞ tracking performance criterion is introduced to minimize the approximation errors and the external disturbance effects. The proposed controller guarantees stability of the overall closed-loop system. Simulation results for a real three-area power system prove the effectiveness of the proposed LFC and show its superiority over a classical PID controller and a type-2 fuzzy controller.

A direct adaptive fuzzy power system stabilizer

A fuzzy power system stabilizer (FPSS) is developed using the concept of fuzzy basis functions. The linguistic rules, regarding the dependence of the plant output on the controlling signal, are used to build the initial FPSS. Based on the Lyapunovs direct method, an adaptation rule is developed in order to make the FPSS adaptive to changes in operating conditions of the power system. The FPSS is designed for a cogenerator, and simulation studies are based-on a one machine-infinite bus model. Nonlinear simulations reveal that the performance of the adaptive fuzzy power system stabilizer (AFPSS) is better than the performance of a conventional (linear) power system stabilizer (CPSS) and a fixed-parameter FPSS for a wide range of operating conditions.

A rule-based fuzzy power system stabilizer tuned by a neural network

A fuzzy logic power system stabilizer (FPSS) has been developed using speed and active power deviations as the controller input variables. The inference mechanism of the fuzzy logic controller is represented by a (7/spl times/7) decision table, i.e. 49 if-then rules. There is no need for a plant model to design the FPSS. Two scaling parameters have been introduced to tune the FPSS. These scaling parameters are the outputs of a neural network which gets the operating conditions of the power system as inputs. This mechanism of tuning the FPSS by the neural network, makes the FPSS adaptive to changes in the operating conditions. Therefore, the degradation of the system response, under a wide range of operating conditions, is less compared to the system response with a fixed-parameter FPSS. The tuned stabilizer has been tested by performing nonlinear simulations using a synchronous machine-infinite bus model. The responses are compared with the fixed-parameter FPSS and a conventional (linear) power system stabilizer. It is shown that the neuro-fuzzy stabilizer is superior to both of them.

Performance evaluation of a narrowband power line communication for smart grid with noise reduction technique

Performance of the narrowband power line communication (PLC) is significantly degraded by the impulsive noise with very large amplitudes and short durations. In practical applications, the simple memoryless nonlinearity techniques (Clipping, Blanking, and Clipping/Blanking) are often used in order to mitigate the effect of the impulsive noise. In this paper, we propose an optimal Clipping/Blanking technique for impulsive noise reduction in narrowband (9-490 kHz) PLC system. This optimal technique is based on the minimum bit error rate (BER) search. To this end, we have derived the transfer function of a typical low voltage (LV) PLC network using the common bottom-up approach and scattering matrix method. Our simulation results, in terms of BER versus signal to noise ratio (SNR), show that the proposed technique slightly improves the BER performance of the narrowband PLC system for smart grid applications and two-way communication between smart meters and utilities1.

Impulsive noise reduction of a narrowband power line communication using optimal nonlinearity technique

In this paper, we propose an optimal Clipping/Blanking nonlinearity technique for impulsive noise reduction in narrowband (9 kHz-490 kHz) PLC system. This optimal technique is based on the minimum bit error rate (BER) search. For our simulation, we have derived the transfer function of a typical low voltage (LV) PLC network using the common bottom-up approach and scattering matrix method. Our simulation results, in terms of BER versus signal to noise ratio (SNR), show that the proposed technique improves the BER performance of the narrowband PLC system.

A channel model for power line communication in the smart grid

Although Power Line Communication (PLC) is not a new technology, its use to support communication with low rate on low voltage (LV) distribution networks is still the focus of ongoing research. In this paper, we propose a PLC channel modeling method based on the bottom-up approach for LV PLC in a narrow, low frequency band between 9 kHz and 490 kHz. We employ the model to derive the transfer function of a typical LV PLC network, which is comprised of two common cable types (copper cables and aluminum conductor steel reinforced). We then investigate the multipath effect of the LV PLC in the studied low frequency bandwidth using numerical computations. Our simulation results based on the proposed channel model show an acceptable performance between neighboring nodes, in terms of bit error rate versus signal to noise ratio, which enables communication required for smart grid applications. Furthermore, we show that data transmission beyond one-hop communication in LV PLC networks will have to rely on upper layer protocols.

Transmission System Augmentation Based on the Concepts of Quantity Withheld and Monopoly Rent for Reducing Market Power

This paper proposes two mathematical structures for considering the market power effect of transmission capacity in transmission augmentation assessment. These mathematical structures use the concepts of monopoly rent and quantity withheld in economics for market power modeling in the assessment process of transmission augmentation. The simultaneous-move and sequential-move games in applied mathematics are used to model the interactions of the transmission network service provider, generating companies, and the market management company in the proposed mathematical structures. The solution concept of Nash equilibria is reformulated as an optimization problem, and the multiple Nash equilibria is tackled through an introduced concept termed worst Nash equilibrium. A numerical solution is developed to solve the proposed mathematical structures. The numerical solution is an island parallel genetic algorithm nested in a standard genetic algorithm. The six-bus Garvers example system and the IEEE 14-bus test system are modified and studied. The results prove the strong mechanism of the developed structures for modeling the market power effect of transmission capacity in the assessment of transmission augmentation.

Dynamic DFIG wind farm model with an aggregation technique

Wind farms begin to influence the power systems with the increasing amount of wind power penetration. The study of such influence justifies the need of a dynamic wind farm model comprising of a large number of generators, but detail models require high simulation computation time. An aggregation technique is required to reduce the model order while maintaining its accuracy. In this paper, a complete and an aggregated wind farm model with Doubly Fed Induction Generator (DFIG) are presented. Simulations have been carried out for both models and compared to demonstrate effectiveness of the aggregated model in terms of accuracy in approximation of the dynamic collective responses at the Point of Common Connection (PCC) and reduction in simulation computation time.

Economic Transmission Augmentation With Explicit Modeling of the Competition Benefit

This paper derives and evaluates a mathematical structure for identifying economically-efficient transmission augmentations. The mathematical structure is based on the concepts of sequential-move and simultaneous-move games in applied mathematics. The Nash equilibrium solution concept has been reformulated as an optimization problem in the proposed structure. The problem of multiple Nash equilibria is managed by introducing the concept of the worst-case Nash equilibrium. Both the economic concepts of the “efficiency benefit” and “competition benefit” of the transmission capacity are explicitly modeled in the proposed structure. A simple three-bus example system and Garvers example system are employed and modified to suit the purpose of analysis. A thorough economic study of these example systems is presented to highlight the concept and operation of the proposed mathematical structure from different perspectives. The results demonstrate the utility of the proposed structure for measuring the total economic efficiency benefit of additional transmission capacity.

A review on transient stability of DFIG integrated power system

With the increasing penetration of doubly fed induction generators (DFIGs), the impact of the DFIG on transient stability attracts great attention. Transient stability is largely dominated by generator types in the power system, and the dynamic characteristics of DFIG wind turbines are different from that of the synchronous generators in the conventional power plants. The analysis of the transient stability on DFIG integrated power systems has become a very important issue. This paper reviews the current research on the issue from two aspects. One is to describe the methods to improve the fault ride through capability of DFIG wind turbines and the other is to analyse the impact of the DFIG wind farm on transient stability of power systems.