No abstract

No abstract

No abstract

Computerization of the accumulation, storage, processing, and evaluation of the result of observations serves to increase the reliability, quality, and promptness of diagnosing the state of structures at the Zagorsk pumped-storage station (PSS). The urgency of computerization of inspection of the state of structures is dictated by the diversity, complexity, and crucial character of the unique hydraulic structures being operated; by the large number of monitored indices of their behavior and monitoring and measuring instruments (MMI) by means of which the latter are measured [1]; by the widespread use of computer engineering. With the use of traditional manual methods of processing and analyzing observation data it is practically impossible to provide timeliness and a high quality of routine information about the state of the hydraulic structures of the PSS.It is a question of creating and putting into operation a databank of observations consisting of a relational database (DB) and software (SW). The DB is a storage of information located in interrelated tables whose structure provides access to information by means of SW and serves for performing functions of processing and analyzing measurement data and evaluating the state of structures of the hydro development.The structure of the bank is based on the conditions, of the observation program [2], data of observations of the structures of the Zagorsk PSS [3], and experience of computerizing data processing gained at the Research Institute of Electronic Systems (NIII~S).Database. The composition of the information of the DB needed for fulfilling functions of inspection of the state of the structures is determined mainly by the objects of diagnosis --list of structures or their integral parts, which require the rapt attention of the operating personnel and are the first feature of the search and selection of data stored in the DB. This list contains the water intake and PSS powerhouse, their abutments, all pipelines and expansion joints, left and right embankments of the upper reservoirs and slopes of the pipelines, structures of the dams and slopes of the lower reservoir, and water areas of the upper and lower reservoirs. The type of observations --either geodetic, or seepage, or visual, etc. --serves as the second feature identifying the information of the DB.Measuring devices (MDs) --a concept which determines the vector of the values measured by means of the appropriate measuring instrument --are the backbone of the DB information. The indicated concept coincides with the generally recognized concept of measuring instrument in the case when one value (component) of a physical quantity is measured by means of it. If two or more components of the same physical quantity (e.g., displacements measured by a three-point gap gauge or plumb line) are measured by the measuring instrument, then to each measured quantity (component) should correspond its own MD. The search for and selection of the MD from the multitude of those located at the hydro development can be done...

Exciting systems of synchronous hydraulic-turbine generators, unlike the main equipment of hydroelectric stations (generators, turbines), are modified rather quickly, including during operation. This is possible due to the rapid interchangeability of the generations of electrical (electronic) elements composing the systems and also because modernization is possible in stages, without interrupting the operation of the main equipment.Therefore a detailed analysis of the hardware of an exciting system developed more than 15 years ago is hardly relevant. Nevertheless, a number of fundamental principles are of interest even today, since the positive solution of certain problems requires changes in the design and construction of the system, which should be taken into account when planning new stations.At the Zagorsk pumped-storage station (PSS) exciting systems of type STSA-300-2000-2.5 with automatic excitation regulators of type ARV-SDP1-21 are installed on all generator-motors. The development, design, and manufacture of the system were carried out by the All-Russian Electrical Machine Construction Research Institute (VNIIl~lektromash) (St. Petersburg) and research-production association Ural61ektrotyazhmash (Ural Heavy Electrical Machinery Plant).Two variants were compared when developing the system --with natural air and water cooling of the thyristors. Since neither one of the variants had explicit economic and technical advantages, the circumstances that thyristor starters with natural air cooling of the thyristors and, furthermore, distilled water is not used either for cooling the generator-motors, i.e., its sufficiently productive source (generator) is absent at the station, were already provided for at the station were taken into account. Therefore the final decision when selecting the design of the converters was made in behalf of natural air cooling.The exciting system provides a standard set of regimes and exciting parameters of the generator-motor in a generator regime and synchronous capacitor regime, and, furthermore, starting in a pump regime (direct asynchronous from the static frequency converter) and electrodynamic braking during stopping of the unit (Table 1).In the case of failure of two parallel branches in any of the arms of the converter or in the case of failure of one branch in each of like arms of both converters during their joint operation as well as in the case of the operation of only one converter with a full number of rectifiers, an exciting current of not more than t250 A is allowed, which is sufficient for operation of the unit in a generator regime. However, a pump regime of the unit in this situation is impermissible.A basic circuit diagram of the exciting system of the generator-motors of the Zagorsk PSS is shown in Fig. 1. The thyristor converters are connected through a converter (rectifier) transformer (RT) to leads of the lowest voltage of the stepup (block) transformer. Such a connection of the rectifier transformer permits starting the reversible unit without an additional ...