\documentclass[journal]{IEEEtran}
%\documentclass[num-refs]{wiley-article}
\usepackage{cite}
\usepackage{amsmath,amssymb,amsfonts}
\usepackage{algorithmic}
\usepackage{graphicx}
\usepackage{textcomp}
\usepackage{xcolor}
\usepackage{multirow}
\usepackage{multicol}
\usepackage{booktabs}
\usepackage{cuted}
\usepackage{multicol}
%\usepackage{subfigure}
\usepackage{epstopdf}
\usepackage{epsfig}
\usepackage{subfigure}
\begin{document}
\title{gffjttymtdymt}
\author{Kp~Yadav,
Pv~Dai}
\maketitle
\begin{abstract}
Small signal stability analysis of the power system is mandatory because slowly growing oscillations may end with the blackout of the system.
\end{abstract}
\begin{IEEEkeywords}
Static Var Compensator, CPSS-Conventional Power System Stabilizer, POD- Power Oscillation Damping, Residue Factor, Participation Factor.
\end{IEEEkeywords}
\IEEEpeerreviewmaketitle
\section{INTRODUCTION}
The modern power system is highly interconnected to meet increasing energy demand and to utilize available sources adequately. The interconnection of the power system is necessary for reliable and flexible operation, so the power system needs to be stable against small or large disturbances such as faults, disconnection of large loads or generators, etc. The stability of the system is strongly influenced by the dynamic behavior of components of the system like generators, loads and other control equipment (FACTs devices).
The disturbances in the system cause change in the electrical torque of the synchronous machine [1]. The change in electrical torque due to disturbances can be divided into two parts and is described by :
\begin{equation}\label{1}
\Delta {T_e} = \Delta {T_{es}}\Delta \delta + \Delta {T_{eD}}\Delta \omega
\end{equation}
The analysis of power system oscillations is of interest in a system where the number of generators are working in parallel for supplying power to a common load. In this type of condition, generators produce torques. These torques act to keep the generators in synchronism (synchronizing torque).
\section{MATHEMATICAL MODELING OF SYSTEM} \label{modelingofstudysystem}
In this section each component of multimachine test system is model in the mathematical form as follows:
\subsection{Synchronous Machine}
The synchronous machine is modeled in the form of equations includes swing equation, rotor and stator voltage equations as follows:
\begin{equation}\label{eq2}
\frac{{d\delta }}{{dt}} = {\omega _B}({s_m} - {s_{mo}})
\end{equation}
\begin{equation}\label{eq3}
\frac{{d{s_m}}}{{dt}} = \frac{1}{{2H}}[ - D({s_m} - {s_{mo}}) + {T_m} - {T_e}]
\end{equation}
\begin{equation}\label{eq4}
\frac{{d{E^'}_q}}{{dt}} = \frac{1}{{{T^'}_{do}}}[ - {E^'}_q + ({x_d} - x{'_d}) + {E_{fd}}]
\end{equation}
\begin{equation}\label{eq5}
\frac{{d{E^'}_d}}{{dt}} = \frac{1}{{{T^'}_{qo}}}[ - {E^'}_d - ({x_q} - x{'_q}){i_q}]
\end{equation}
\begin{equation}\label{eq6}
{T_e} = {E^'}_q{i_q} + {E^'}_d{i_d} + (x{'_d} - x{'_q}){i_d}{i_q}
\end{equation}
\section{Conclusion} \label{conclusion}
Power system oscillations can lead the system towards the shutdown. Hence, to damp out these
\end{document}
答案1
你的（最後三個）方程式中有很多錯誤
- 而不是
${E^'}_{d}$正確的$E'_{d}$或$E'_d$ - 你的方程式中有太多的花括號，因此很容易迷失其中...
完整（真實）MWE：
\documentclass[journal]{IEEEtran}
\usepackage{cite}
\usepackage{amsmath,amssymb}
\begin{document}
\begin{equation}\label{1}
\Delta {T_e} = \Delta {T_{es}}\Delta \delta + \Delta {T_{eD}}\Delta \omega
\end{equation}
\begin{equation}\label{eq2}
\frac{{d\delta }}{{dt}} = {\omega _B}({s_m} - {s_{mo}})
\end{equation}
\begin{equation}\label{eq3}
\frac{{d{s_m}}}{{dt}} = \frac{1}{{2H}}[ - D({s_m} - {s_{mo}}) + {T_m} - {T_e}]
\end{equation}
\begin{equation}\label{eq4}
\frac{d E'_q}{dt} = \frac{1}{T'_{do}}[ - E'_q + (x_d - x'_d) + E_{fd}]
\end{equation}
\begin{equation}\label{eq5}
\frac{dE'_d}{dt} = \frac{1}{T'_{qo}}[ - E'_d - (x_q - x'_q) i_q]
\end{equation}
\begin{equation}\label{eq6}
T_e = E'_q i_q + E'_d i_d + (x'_d - x'_q) i_d i_q
\end{equation}
\end{document}
編輯： 根據 @egreg 評論，你的方程式可以寫成：
\documentclass[journal]{IEEEtran}
\usepackage{cite}
\usepackage{amsmath,amssymb}
\begin{document}
\begin{gather} % <---
\Delta {T_e} = \Delta {T_{es}}\Delta \delta + \Delta {T_{eD}}\Delta \omega
\label{1} \\
\frac{{d\delta }}{{dt}} = {\omega _B}({s_m} - {s_{mo}})
\label{eq2} \\
\frac{{d{s_m}}}{{dt}} = \frac{1}{{2H}}[ - D({s_m} - {s_{mo}}) + {T_m} - {T_e}]
\label{eq3} \\
\frac{d E'_q}{dt} = \frac{1}{T'_{do}}[ - E'_q + (x_d - x'_d) + E_{fd}]
\label{eq4} \\
\frac{dE'_d}{dt} = \frac{1}{T'_{qo}}[ - E'_d - (x_q - x'_q) i_q]
\label{eq5}
\intertext{and finally:}
T_e = E'_q i_q + E'_d i_d + (x'_d - x'_q) i_d i_q
\label{eq6}
\end{gather}
\end{document}
