International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 13 Issue: 06 | Jun 2026
p-ISSN: 2395-0072
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Transient Stability Analysis of Synchronous Generator In Multi Machine System Using Time Domain Method, Direct Method and AI Method Dipkumar S. Trivedi1, Arpit R. Joshi2 1, 2Lecturer, Department of Electrical Engineering, K. D. Polytechnic, Patan, Gujarat, India
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Abstract – This paper presents transient stability analysis
(i) Time domain method, (ii) Direct method, (iii) Approximation method and (iv) Artificial intelligence method.
of synchronous generator in multi machine system using time domain method, direct method and artificial intelligence method in MATLAB. A Multi Machine, two generator and nine bus system is used for this analysis. A three line to ground fault is considered for this analysis. Transient stability of multi machine system is analyzed by Critical Clearing Time (CCT) then CCTs of the system are compared for different methods in this paper.
Time domain method is a traditional method of transient stability analysis based on time domain numerical integration [3]. Important conclusions and decisions depend on the stability analysis results, So that the stability analysis results should be accurate and within time limit as possible [7]. The stability of the post fault system is analysed based on simulated post fault trajectories. The typical simulation period for the post fault system is about 10 to 15 second.
Key words: Transient stability analysis, Critical Clearing Time, Synchronous Generator, Multi machine system, Direct method, AI method
1. INTRODUCTION
System simulation takes approx. 10 to 20 second [7]. In time domain method, detail modelling is required of the whole components of the power system for more accuracy. Advantages of time domain method are: this is an accurate method. It can be used directly for any level of modelling. For transient and steady state, all type of information can be determined using this method. This method can provide dynamic parameters of the system using swing curves like rotor angles (δ), speeds (N); accelerations; powers etc[3][7]. Disadvantages of time domain method are: It is a time consuming method (10 to 20 second) No measure of degree of stability and degree of instability are provided by time domain method. No information for preventive control is given. Its cost is higher than direct method [3][7].
Electricity has important role in the human life. That is why power system should be reliable and stable. Stability of the power system affects directly to the human life, industries production and economy of the country. That is why stability of power system becomes very important. Power system stability can be defined as the ability of a power system to remain in synchronism before, during and after the fault on the system [1][2]. In transient stability point of view, during normal operating conditions of the power systems, synchronism of the system should be maintained and frequency of the all system buses should be same [4]. During steady state condition, input mechanical power and electrical power of each generator should be in balance. But due to occurrence of fault on the system, this power balance is disturbed and system start to accelerate or decelerate. This unbalance of mechanical and electrical power provides the concept of swing equation. If disturbance is small then analysis is known as small signal analysis and if disturbance is large then analysis is known as transient analysis. Power system must have ability to recover and maintain stability after disturbance. The ability of a power system to recover and maintain synchronism is called rotor angle stability.[2] Small signal stability is the ability of the power system to maintain synchronism under small disturbances.[2] Transient stability is the ability of the power system to maintain synchronism under large disturbances.[2]
Main disadvantage of time domain method is more time consumption in transient stability analysis. To overcome this problem, direct method had come into picture. Direct method is energy based method. This is the extensions of equal area criterion for multi machine system which is shown by the classical model. Advantages of Direct methods are: direct methods without the solution of differential equations can be used to determine the transient stability analysis of power system. It is a faster method than time domain methods. It gives the measurement of the degree of the stability of system. It provides important information related to derivation of preventive control and enhancement action of control. Challenges of direct method are modeling and reliability. Limitation of direct method is accuracy of the analysis [3][7]
In literature, for transient stability analysis, mainly four methods are given. These methods are:
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