Rajesh Damaraju ¹, S. V. N. L. Lalitha ¹

Affiliations
1 Department of EEE, KL University, Vaddeswaram, Guntur - 520002, Andhra Pradesh, IN

Abstract

The main aim of this paper is to enhance the power quality problems in-terms of voltage sag and swell. Generally, these problems occur in a power system during fault conditions and presence of high voltages. The system may damage if long presence of these power quality problems. In order to protect the system this paper proposes a concept of dynamic voltage restorer which is type of flexible ac distribution system device. And the control diagram for this device is designed using inphase compensation algorithm. A fuzzy controller is also proposed in this paper for better controlling action. This system is verified using matlab/simulink.

Keywords

Dynamic Voltage Restorer (DVR), Fuzzy controller, Harmonics, Sag/Swell

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Yasaswini ¹, S. V. N. L. Lalitha ¹, Shefali Talati ²

Affiliations
1 Electrical and Electronics Engineering, K L University, Vijayawada - 522502, Andhra Pradesh, IN
2 Electrical Research and Development Association, Vadodara - 390010, Gujarat, IN

Abstract

Objectives: To design multi-voltage multi-circuit transmission tower to reduce right of way (RoW). Methods/Statistical Analysis: In order to reduce right of way structural optimization and electro-magnetic analysis should be carried out. Structural optimization includes various factors like conductor configuration, cross arm arrangement, wind loadings. The tower is designed using Staad Pro and the structure is validated for various wind loadings and stresses. Electro-static and magneto-static fields around the tower are analyzed and are brought down to limits by choosing optimal phase sequence. This analysis is carried out using Ansoft Maxwell. Findings: The designed structure withstands all the permissible stresses. Electro-static and magneto-static fields around the designed tower are found to be within the specified limits specified by standards. This design is found to be cost effective with respect to right of way when a transmission line is considered. Application / Improvements: Narrow base width is considered which also aids in optimized right of way. This tower design can hold three voltages (400kV, 220kV, 33kV) and six circuits. The height of the tower is maintained in normal range by structural optimization.

Keywords

MVMCT, Narrow based Tower, Right of Way

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Sravya Pentela ¹, S. V. N. L. Lalitha ¹

Affiliations
1 K L University, Vaddeswaram, Guntur district – 520002, Andhra Pradesh, IN

Abstract

Objectives: In re-structured power systems, knowledge of reactive power supplied by the ancillary services and generators is required separately for accurate and fair cost allocation. The main objective is to price the reactive power based on each generator contributions and static capacitor contributions to individual loads. Methods/Analysis: A Y-bus matrix method is used to obtain the contribution of individual buses to loads. But this bus contribution doesn't give the fair cost allocation. So, the individual generator contributions should be found. Findings: To find the individual generator contributions a new methodology is proposed in this paper. This new methodology takes the bus inflows and outflows into consideration for finding the bus injections at the generator buses. Using this data, the contribution of generators to the loads can be obtained which gives rise to fair and transparent cost allocation. Applications: This method is applied on simple 5 bus system and on IEEE 30 bus system and obtained results are tabulated and compared with other existing methods.

Keywords

Ancillary Services, Contribution of Generators, Cost Allocation, Reactive Power, Re-structured Power Systems.

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J. N. S. Mrudveeka ¹, S. V. N. L. Lalitha ¹, M. Ramamoorty ¹

Affiliations
1 EEE, K L University, Vaddeswaram, Guntur district - 520002, Andhra Pradesh, IN

Abstract

Objective: Load modelling has a prominent place in present scenario of power systems research. In this paper various load models are considered for assessing maximum loadability using new algorithms. This has got a lot of significance in the voltage stability studies. Methods/Analysis: Generally constant representation of loads was considered. But the load characteristics significantly affect the power system’s performance. Constant models can not accurately describe the actual nature and behaviour of loads. Findings: Constant Power, Constant Impedance, Constant Current as well as composite (ZIP) load model are considered for assessing maximum loadability using a new algorithm. Constant Impedance, Constant Current Load models are established using node elimination technique. Application/Improvements: Case studies are conducted on IEEE 14 bus system with different load models and the test results are compared.

Keywords

Constant Current Model (I), Constant Impedance Model (Z), Constant Power Model (P), Maximum Loadability, ZIP Model

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B. Mounika ¹, S. V. N. L. Lalitha ¹, M. Ramamoorty ¹

Affiliations
1 EEE, K L University, Vaddeswaram, Guntur District – 520002, Andhra Pradesh, IN

Abstract

Objective: State estimation is used as a necessary tool for online monitoring, analysis and control of power systems. The main objective of this paper is to deal with static state estimation using the snap shot data and dynamic state estimation which accounts for the time varying behaviour of power system states in to consideration. Methods/Analysis: Effects of inclusion of PMU measurements along with the available metered data have been explored using the weighted least square state estimation technique in this paper. A comparative analysis of static state estimation with and without bad data has been carried out and the bad data has been identified and eliminated by using largest normalized residue test. Findings: To investigate the time varying nature of the system states linear state estimator with second order approximation and kalman filter techniques has been proposed in this paper. Case studies are conducted on IEEE 14 bus test system and the test results obtained from non linear, linear first order, second order and kalman filter techniques have been compared. Application/Improvements: Correction of state variables are obtained using linear state estimation with first order and second order approximation and kalman filter techniques has been compared to get the better state estimation algorithm.

Keywords

Bad Data, Kalman Filter, PMU, State Estimation, Static, Dynamic, Weighted Least Squares.

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