• Energy Research

Abstract This paper addresses comprehensive dimensioning of series braking resistors designed to improve transient stability of the power system. Since dynamic braking is one of the most cost-effective ways to improve transient stability, the applications of shunt and series braking resistors have recently expanded in the power industry. To find an effective algorithm for controlling series braking resistors appropriate resistor dimensioning should be performed first. This paper addresses the problem of dimensioning of series braking resistors. To solve that problem a mathematical model is employed for different operating states of the system equipped with a series braking resistor. This paper describes and discusses in detail the impact of series braking resistors on: power angle characteristics, intensity of dynamic braking in terms of transient stability improvement, voltage dynamic response during and after a fault, and turbo-generator shaft fatigue. Based on the analysis performed, criteria for the dimensioning of series braking resistors are formulated. Theoretical considerations are supported by simulation tests for nonlinear models of single-machine as well as multi-machine test systems.

Abstract This paper addresses comprehensive dimensioning of series braking resistors designed to improve transient stability of the power system. Since dynamic braking is one of the most cost-effective ways to improve transient stability, the applications of shunt and series braking resistors have recently expanded in the power industry. To find an effective algorithm for controlling series braking resistors appropriate resistor dimensioning should be performed first. This paper addresses the problem of dimensioning of series braking resistors. To solve that problem a mathematical model is employed for different operating states of the system equipped with a series braking resistor. This paper describes and discusses in detail the impact of series braking resistors on: power angle characteristics, intensity of dynamic braking in terms of transient stability improvement, voltage dynamic response during and after a fault, and turbo-generator shaft fatigue. Based on the analysis performed, criteria for the dimensioning of series braking resistors are formulated. Theoretical considerations are supported by simulation tests for nonlinear models of single-machine as well as multi-machine test systems.

For economic reasons, expansions of transmission networks are based on a compromise between capital cost and security of power system operation. At the same time, the power system must withstand typical highly likely contingencies. Various emergency state control systems, also called special protections, prevent emergencies following less likely contingencies. This paper describes overloads emergency state control (OLEC) used for the alleviation of overload in transmission networks near a power plant. Such control uses the functions of automated power reduction of generating units and has been implemented for a large steam power plant. The OLEC presented here uses different methods of generation curtailment for steam generation units. A case study illustrates the efficiency of the proposed control method.

For economic reasons, expansions of transmission networks are based on a compromise between capital cost and security of power system operation. At the same time, the power system must withstand typical highly likely contingencies. Various emergency state control systems, also called special protections, prevent emergencies following less likely contingencies. This paper describes overloads emergency state control (OLEC) used for the alleviation of overload in transmission networks near a power plant. Such control uses the functions of automated power reduction of generating units and has been implemented for a large steam power plant. The OLEC presented here uses different methods of generation curtailment for steam generation units. A case study illustrates the efficiency of the proposed control method.

Transmission expansion planning requires static and dynamic analyses. Planning criteria include the selection of contingencies consisting of faults and their clearing, performance standards, transmission system adjustments, and corrective action plan. Performance standards relating to power system dynamics mainly concern the voltage ride through and transient angle stability i.e. retaining synchronism after the occurrence of the contingencies mentioned. The selection of planning contingencies, for which performance standards must be complied with, is important in terms of capital expenditures in transmission network expansion and secure power system operation. This paper discusses planning contingencies accepted by various transmission network operators worldwide and describes a set of planning contingencies proposed by the authors.

Transmission expansion planning requires static and dynamic analyses. Planning criteria include the selection of contingencies consisting of faults and their clearing, performance standards, transmission system adjustments, and corrective action plan. Performance standards relating to power system dynamics mainly concern the voltage ride through and transient angle stability i.e. retaining synchronism after the occurrence of the contingencies mentioned. The selection of planning contingencies, for which performance standards must be complied with, is important in terms of capital expenditures in transmission network expansion and secure power system operation. This paper discusses planning contingencies accepted by various transmission network operators worldwide and describes a set of planning contingencies proposed by the authors.

Abstract Transmission network expansion planning involves various types of static and dynamic analyses. The complexity and increasingly difficult operating conditions of power systems raise the importance of dynamic analyses on the expansion planning stage. Primary studies in the field of dynamic analyses include rotor angle stability, voltage ride-through and frequency stability analyses. This paper presents four methods of rotor angle small signal stability assessment, which can be used in transmission network expansion planning. For each of these methods, the requirements for the calculation model and computational accuracy are discussed, among other aspects. Practical considerations related to the use of particular methods in planning analyses are presented. Theoretical considerations are illustrated with the results of stability assessment of a multi-machine test system.