18-03-2011, 02:40 PM
Presented by:
Mohd Abdul Aziz
[attachment=10498]
SUPERVISORY CONTROL AND DATA ACQUISITION
System based control for HVDC links
Abstract
Scada system has been used successfully to address some of the practical control problems. This paper introduces a practical control for a point to point HVDC link, based on the above system. The SCADA system is used to monitor the faults and to clear the faults. A ladder logic program has been dumping into a PLC. The simulation results presented in this paper prove the advantage of the proposed control scheme. This paper is an attempt to highlight the features of SCADA on hvdc links, which is a revolutionary development in automotive monitoring and control of process © 1999 Elsevier Science S.A. All rights reserved.
Keywords: SCADA; PLC; HVDC link.
1. Introduction
SCADA’s powerful tools are being increasingly used for centralized control of remote processes to optimize operation of really complex systems such as automation of energy transmission, and generation of electricity. The inherent non-linearity involved in an HVDC page link operation makes it difficult to design appropriate controllers under different normal and abnormal situations. The rate of change of the DC page link current is highly sensitive to the firing angles on either side, due to the non-linear relationship between them. This leads to severe oscillations in DC page link current and voltage waveforms as soon as a fault is cleared or the page link is energized. These excursions impose a great deal of constraints in designing the converter valves, circuit breakers, reactors and filter banks. Sometimes the high value of di/dt can damage the associated equipment, especially the thyristor valves. Literature available in the DC adaptive control [1] is inconclusive of it’s practical application under large signal conditions. Several authors propose gain scheduling
controllers for HVDC links for these conditions. Recently Reeve et al. has tried a gain scheduling adaptive
Control strategy for HVDC links [2,3]. Hammedet al. has developed a coordinated control scheme based on optimal control strategy for parallel AC–DC
systems.
In this paper a new simplified control strategy based on the scada system approach has been developed. This system has been used to control the firing angle for the converter valves. In the end, the simulation carried out using programming logic controller (PLC).
2. HVDC system model
A two-pole point-to-point 6-pulse HVDC system has been simulated with the help scada system
The filters and transformers on either side of the DC page link and the transmission line are represented in detail. The system shown in Fig. 1 is divided into four subsystems:
2.1. Subsystem 1
The rectifier side subsystem consists of a constant voltage and constant frequency source behind an impedance that comprises inductance and resistance to * Corresponding author. represent a simplified AC system. The short circuit
Mohd Abdul Aziz
[attachment=10498]
SUPERVISORY CONTROL AND DATA ACQUISITION
System based control for HVDC links
Abstract
Scada system has been used successfully to address some of the practical control problems. This paper introduces a practical control for a point to point HVDC link, based on the above system. The SCADA system is used to monitor the faults and to clear the faults. A ladder logic program has been dumping into a PLC. The simulation results presented in this paper prove the advantage of the proposed control scheme. This paper is an attempt to highlight the features of SCADA on hvdc links, which is a revolutionary development in automotive monitoring and control of process © 1999 Elsevier Science S.A. All rights reserved.
Keywords: SCADA; PLC; HVDC link.
1. Introduction
SCADA’s powerful tools are being increasingly used for centralized control of remote processes to optimize operation of really complex systems such as automation of energy transmission, and generation of electricity. The inherent non-linearity involved in an HVDC page link operation makes it difficult to design appropriate controllers under different normal and abnormal situations. The rate of change of the DC page link current is highly sensitive to the firing angles on either side, due to the non-linear relationship between them. This leads to severe oscillations in DC page link current and voltage waveforms as soon as a fault is cleared or the page link is energized. These excursions impose a great deal of constraints in designing the converter valves, circuit breakers, reactors and filter banks. Sometimes the high value of di/dt can damage the associated equipment, especially the thyristor valves. Literature available in the DC adaptive control [1] is inconclusive of it’s practical application under large signal conditions. Several authors propose gain scheduling
controllers for HVDC links for these conditions. Recently Reeve et al. has tried a gain scheduling adaptive
Control strategy for HVDC links [2,3]. Hammedet al. has developed a coordinated control scheme based on optimal control strategy for parallel AC–DC
systems.
In this paper a new simplified control strategy based on the scada system approach has been developed. This system has been used to control the firing angle for the converter valves. In the end, the simulation carried out using programming logic controller (PLC).
2. HVDC system model
A two-pole point-to-point 6-pulse HVDC system has been simulated with the help scada system
The filters and transformers on either side of the DC page link and the transmission line are represented in detail. The system shown in Fig. 1 is divided into four subsystems:
2.1. Subsystem 1
The rectifier side subsystem consists of a constant voltage and constant frequency source behind an impedance that comprises inductance and resistance to * Corresponding author. represent a simplified AC system. The short circuit
