tailieunhanh - Electrical Power Systems Quality, Second Edition phần 10

Biển hiệu của máy biến áp, động cơ, vv 2. Thiết bị đo đạc thiết lập 3. Đầu dò và kết nối đầu dò 4. Key dạng sóng hiển thị từ các công cụ 5. Trạm biến áp, sắp xếp thiết bị chuyển mạch, các vị trí bị chặn, vv 6. Kích thước của các thành phần điện chẳng hạn như máy quay video độ dài cáp là tương tự hữu ích khi di chuyển hành động hoặc sự kiện ngẫu nhiên. | Power Quality Monitoring Power Quality Monitoring 475 1. Nameplates of transformers motors etc. 2. Instrumentation setups 3. Transducer and probe connections 4. Key waveform displays from instruments 5. Substations switchgear arrangements arrester positions etc. 6. Dimensions of key electrical components such as cable lengths Video cameras are similarly useful when there is moving action or random events. For example they may be used to help identify the locations of flashovers. Many industrial facilities will require special permission to take photographs and may place stringent limitations on the distribution of any photographs. Oscilloscopes An oscilloscope is valuable when performing real-time tests. Looking at the voltage and current waveforms can provide much information about what is happening even without performing detailed harmonic analysis on the waveforms. One can get the magnitudes of the voltages and currents look for obvious distortion and detect any major variations in the signals. There are numerous makes and models of oscilloscopes to choose from. A digital oscilloscope with data storage is valuable because the waveform can be saved and analyzed. Oscilloscopes in this category often also have waveform analysis capability energy calculation spectrum analysis . In addition the digital oscilloscopes can usually be obtained with communications so that waveform data can be uploaded to a personal computer for additional analysis with a software package. The latest developments in oscilloscopes are hand-held instruments with the capability to display waveforms as well as performing some signal processing. These are quite useful for power quality investigations because they are very portable and can be operated like a voltohm meter VOM but yield much more information. These are ideal for initial plant surveys. A typical device is shown in Figs. and . This particular instrument also has the capability to analyze harmonics and permits .