由于一些工业发达国家水力资源的大力开发,最有利的水电点子逐渐减少。近年来太多国家又重新重视中小型水电站的发展。在这些中小型水电站开发点子中,有建设低水头、长压力引水系统水电站的趋势。 由于有些水电站受缓坡地形条件约束,在布置较长的压力引水系统时,为了使机组处于稳定工况运行,就必须布置调压井。但调压井位置又限于地形条件,往往需要延长压力钢管,从而增加了水电站的土建工程量和建设投资。 为了减少水电站的工程量和投资,故提出了在长压力引水系统水电站布置中不设调压井的设想,国外有些水电站经过多年研究实践实现了不设调压井的布置形式。其主要措施之一,是控制机组甩负荷时压力引水系统中的水压上升值,降低到允许的范围内。 Due to the vigorous development of hydraulic resources in some industrially developed countries, the most favorable hydro power point has been gradually reduced. In recent years, too many countries have re-emphasized the development of small and medium hydropower stations. Among these small and medium-sized hydropower development projects, there is a tendency to build hydropower stations with low head and long pressure diversion systems. As some hydropower stations are constrained by the gentle slope topography conditions, when arranging longer pressure diversion systems, it is necessary to arrange surge tanks in order to operate the unit in a stable condition. However, the location of the surge shaft is limited to the topographic conditions and often requires the extension of the pressure pipe, thus increasing the amount of civil works and construction investment of the hydropower station. In order to reduce the amount of hydropower stations and investment, it is proposed in the long-pressure diversion system of hydropower station without surge tank design, some hydropower stations abroad after years of research and practice to achieve no surge tank layout. One of its main measures is to control the water pressure rise in the pressure diversion system when the unit discharge load is reduced to the allowable range.