Fault Location Using Sparse Wide Area Measurements
Transmission line fault location allows quick repair of the damage caused by the fault and timely restoration of the line affected by the fault. Accuracy of the fault location is quite important since it affects repair crew’s ability to physically locate the damage part quickly. Typically, the desirable accuracy is to be able to locate a fault within a span of the transmission line towers. This paper presents a new fault location scheme which uses synchronized phasor measurements from different substations sparsely located near the region where the fault has occurred. When fault occurs different Intelligent Electronic Devices (IEDs) such as Phasor Measurement Units (PMUs) and Digital Fault Recorders (DFRs) connected to Global Positioning System (GPS) receivers and installed in some of the substations in the region will be automatically triggered by the change in monitored signals and will record corresponding current, voltage and status signals. Apart from these sparse measurements, the proposed method also uses SCADA PI Historian data which is utilized for tuning the power system model data with the pre-fault condition in real time information. The paper presents how the technique is implemented and shows test results using actual power system model as well as actual field data from a utility company that supported demonstration of the technique. The results are quite encouraging since the sparse measurement problem for such unique transmission line configurations does not allow any other known techniques to produce accurate and reliable results while the proposed technique produces satisfactory results.
Converting Field Recorded Data to Information: New requirements and concepts for the 21 st century automated monitoring solutions
SUMMARY Automated monitoring of power systems has become an imperative due to two major developments that characterize the 21 st century electricity grid: a) large scale deployment of intelligent electronic devices (IEDs) has created huge amount of data recorder either continuously or at the time when IED recording is triggered by an event such as disturbance or fault, and b) the power system loading has increased to the point where it operates close to the limits, which requires much better monitoring capability than what is available today to make sure such operation does not create undesirable consequences such as cascading failures. Fully aware of the challenges the North American Electric Reliability Corporation (NERC) has developed standards for event monitoring and reporting, which will assure the bulk electricity system is reliable, adequate and secure. To fulfil NERC and/or internal requirements for improved monitoring utilities have started deploying advance solutions that enable automated collection of field data, extraction of information and distribution of monitoring reports so that the utility staff can respond to the events expeditiously. The deployment exaples illustrated in this paper are aimed at demonstrating various deployment strategies that are possible with such solutions: substation, distributed and centralized-based processing. The substation processing requires installation of a PC that serves as the integration hub which collects recorded files from all substation IEDs, converts data to information and creates event reports that are sent to the groups that need them. The distributed solution retrieves IED records and passes them to a location such as protection office, operator control room or maintenance canter where further processing is done. The centralized solution collects all the data to a centralized database, extracts information and sends it to the users per request. To illustrate the above concepts several hardware and software solutions are developed and deployed in the field: circuit breaker recorder, automated analysis of circuit breaker recorder (CBR) data, automated analysis of digital protective relay (DPR) data, automated analysis of digital fault recorded (DFR) data, automated integration of substation IED data, automated handling of user interfaces. All the solutions are implemented using advanced hardware and software concepts that allow the recorded data to be synchronized and time stamped utilizing receivers for Global Position System (GPS) of satellites. Time stamped data are communicated through variety of modern communication media such as wireless, optical fibre and high speed coaxial cable links. Handling of software applications is through advanced JAVA programming, and user interfaces deploy latest advancements in the web browsers and graphical user interfaces. Practical issues such as cyber security, implementation steps and personnel acceptance are addressed as well.
Accurate measurements of output characteristics and detonations of motorbike high-speed racing engine and their optimization at actual atmospheric conditions and combusted mixture composition
Abstract At a motorbike high speed racing engine there is very important an output engine characteristics which depends significantly on a detonation combustion rate, atmospheric conditions and a combusted mixture composition. The combustion process has got a relevant influence on a wear degree of main engine parts or on their damage eventually. The detonation combustion rate is very important because this kind of burning can be not only destructive but a useful phenomenon, as well. If the process of detonation burning is kept on a certain level, it can help significantly to the next increasing of an engine power output. In this article there is described the measurements of output characteristics of a high-speed racing engine which were performed by means of a data-recording system and the detonation combustion was evaluated using a quantitative method. The actual values of atmospheric conditions and the mixture composition were added to the measured values. Then the obtained values are compared visually with a damage degree of an engine piston caused by the detonation burning. The result is a limit value expressed in a number of detonation units related to a run distance interval of the vehicle driven by the high-speed racing engine. In framework of this run distance interval there is the process of detonation burning profitable. As well as it increases an engine power output and together it is not destructive with regard to engine design parts.