Generally speaking, the hydraulic turbine equipment maintenance technology is divided into three categories: fault maintenance (post-hoc maintenance) performed after a fault occurs, preventive maintenance for periodic decomposition inspection, and predictive maintenance (predictive maintenance) for prediction and processing based on diagnostic data. These are the meanings of preventive maintenance in a narrow sense. In a broad sense, preventive maintenance also includes the prevention of failures, the determination of the location and cause of failures, the determination of early recovery methods and methods, and safe operation and return operations. The following is a brief overview of related technologies in a broad sense.
The purpose of preventive maintenance is generally divided into three aspects: economic improvement, technical capability improvement and quality (reliability) improvement.
The outline of the preventive maintenance system of a hydropower station is described below. The structure of the system is roughly divided into a centralized monitoring device (head office) in the control office and an individual monitoring device (branch office) in each power station connected by a modem (transmission device). The branch office is further divided into a sensor unit for measurement status, a CPU unit for performing calculation processing, and a keyboard. CRT and other human-computer dialogue departments. Similarly, the main office is also divided into two parts: CPU department and man-machine dialogue department.
Status and status of faults in hydropower stations
According to the statistics of equipment failures of hydropower stations in the past 10 years published in the Technical Report of the Institute of Electrical Engineering, most of the failures related to Hydraulic Turbine Generator occurred in water supply and drainage equipment, followed by the turbine body, oil pressure equipment, etc., the number of failures was about Occurs more than once every two years. In addition, from the failure rate of various parts of these devices, the oil supply equipment of oil pressure equipment such as the guide vanes of the turbine body of the water supply and drainage devices, valves, filters, and water pumps, and the water sealing device around the Guide Vanes, valves, oil pumps and other components have a high failure rate. In addition, according to the cause classification, failures that are natural degradation account for an overwhelming majority, followed by poor implementation, poor manufacturing, and poor maintenance.
Hydraulic Turbine Generator
Most fault pairs will be accompanied by changes in some state quantities. It is much easier to manage them if they are centralized and classified. These state quantities are called related state quantities. For water supply and drainage devices, it means the increase of water pressure, flow, vibration, etc. Similarly, for hydraulic turbine bearings, it refers to the amount of metal wear, bearing temperature, vibration value, etc. For the casing, runner, suction pipe, etc. It refers to noise, vibration, etc. For oil pressure devices, it means oil pressure, oil level, operation time and frequency of load relief valve, etc. For main shaft water sealing device, it means the increase of water leakage, etc.
One of the important purposes of preventive maintenance is to use daily monitoring of temperature, vibration and other conditions to predict failures in advance. There are two methods here, one is to find out the trend of the daily or monthly maximum value listed, and then predict when it will cross a given limit. Another method is to find signs of anomalies from changes in the above data.