Transient stability analysis of VSC HVDC transmission with power injection on the DC-link

Abstract

Abstract:The utilization of a DC-link transmission corridor of embedded VSC HVDC for a DC power injection from renewable energy sources to increase the power flow capability and AC network stability support is a promising technology.However, DC faults on the DC transmission line are likely to threaten the system's operation and stability, especially when the DC power injection exceeds certain limits. A DC single line-to-earth fault is the most likely fault scenario and its effect on the VSC HVDC operation will depend on the earth-loop impedance. Adding an injection point on the DC-link will reduce the earth-loop impedance, hence imposing a danger of increasing the earth fault current. Therefore, in this paper, a VSC HVDC with a DC power injection on the DC-link is studied, the DC-line-to-earth fault is analyzed in the time domain, and its effects on the DC and AC sides of the system are presented. The analysis is based on a developed state-space representation of the system under a single-line-to earth fault. The zero-input zero-state (ZIZS) response is used to find the solution of the state-space representation. In order to correlate the state-space solution with a simulation, the system is modeled in MATLAB/Simulink. Interestingly, it was observed that a quick recharging of the DC-link capacitor due to a power injection created an additional damping of the postfault oscillations of the AC-side power angle and the DC-side voltage and power oscillations, hence enhancing transient stability.

Research on Hazard Analysis and Control Strategy of Power System Dispatching Operation Based on Information Fusion Technology

“…Along with the rapid development of the national economy, the development of electric power systems is very rapid. The voltage level of the power transmission network is getting higher and higher compared with the original one, the grid structure is becoming more and more complex, and the sources of electric energy and the nature of the user's load are becoming more and more diversified [4][5][6]. Power dispatching is a critical task in the electric power industry, and its effectiveness is directly related to the operational safety and stability and even the economy of the transmission network [7][8].…”

Adaptive sliding mode with time delay control based on convolutions for power flow reference tracking using a VSC-HVDC system

“…(11), the term ∆P = P s − P r represents the DC link control and P loss is considered as a disturbance that is assumed to be unknown. Since the dynamics of the DC link is linear and relatively slow, a conventional PI controller can be used to regulate DC voltage U C2 to its rated value U C2ref and reject external disturbances P loss [6][7][8][9][10][11][12][13][14][15][16], as shown in Figure 5. …”

“…We intend to develop a state feedback control that forces the system to track a nonconstant reference current 2154 X ref (t) in the presence of plant uncertainties and external disturbances that unavoidably affect the state space model Eq. (5) [6][7][8][9][10][11][12][13][14][15][16].…”

“…Its various capabilities have been discussed in many papers in areas of power flow control [6][7][8], transient stability improvement, and oscillation damping control [9,10]. Furthermore, in the literature, the HVDC transmission system has been applied in a vast variety of control system investigations, including PI control [11][12][13][14], H ∞ approach method [15], linearization control [11], sliding mode control [16,17], backstepping design [18,19], flatness theory-based control [20], and passivity theory-based control [21,22].…”