■Technical water supply of hydropower station

The main function of cooling water in the water supply system of hydropower station is to cool the main equipment. The equipments that need cooling water include generator air cooler, thrust bearing, upper guide bearing, lower guide bearing, water-cooled transformer and air compressor, etc. When the cooling water can not meet the requirements of the above equipment for water quality, water quantity, water pressure and water temperature, the temperature of the generator set will continue to rise until the shutdown. Even the motor and bearing bush will be burned, which will seriously affect the production of the whole power station and cause losses to investors.

Traditional water supply system of hydropower station adopts gravity water supply, direct water supply from pump to mixed water supply. The water source is usually taken by penstock or spiral case, water intake in front of dam, tail water pumping, etc. However, hydropower stations are located in mountainous rivers, and the water quality is often not guaranteed due to the influence of river sediment, floating objects, aquatic organisms, hardness or acid hardness. With the destruction of the environment by human beings, the water quality of various rivers is getting worse and worse, which has a greater impact on the power generation industry.

■Principle of external circulation cooling water supply system

First of all, sufficient clean water is injected into the circulating water pool, which is pumped by the pump to the circulating cooler arranged in the tail water, and then the water enters into and exchanges with the natural river water in the river channel to reduce the cooling water temperature. Then, the water is sent to each water consumption place of the unit through the technical water supply pipe to take away the high temperature generated during the operation of the unit, and then return to the circulating pool through the return pipe, so as to circulate continuously (see figure below).

尾水冷却器→机组→循环水池→供水泵→再到尾水冷却器形成一个封闭的循环圈

Tail water cooler → unit → circulating pool → water supply pump → tail water cooler to form a closed circulation circle

■Superiority of circulating cooling water supply system in Hydropower Station

The circulating cooling water system is relatively independent, and the circulating water adopts clean water, which is not affected by the external environment. It can effectively prevent blockage, scaling, corrosion and aquatic organisms, and thoroughly solve the quality problems of cooling water required by hydropower units. It improves the stability and safety of unit operation, reduces the probability of shutdown caused by cooling water system failure, and increases the power generation.

The circulating cooler is easy to install and maintain, easy to operate and long service life. It is convenient for power station to realize automatic control. Practice has proved that this technology can be widely used in hydropower stations and pumping stations with various installed capacity, various water head ranges, various models (mixed flow, axial flow, tubular flow, impact type) and various plant layout forms (diversion type, dam back type, riverbed type, underground type and mixed type, etc.).

The circulating cooler is a non-standard product, and each power station should be designed and manufactured independently according to the specific situation. In order to match the layout of the power plant, the overall dimensions and layout of the circulating cooler can be flexibly adjusted on the premise of ensuring the heat dissipation area and structural stiffness requirements. In the technical transformation project, this characteristic is particularly important.

■The composition of circulating cooling water supply system of hydropower station is as follows

The equipment of circulating cooling water supply system includes: circulating water tank (water tank), circulating cooler, water supply pump, water pump control cabinet and automatic components. Our company can provide complete sets of:

1. Circulating water tank

The circulating water tank is mainly used for the first water filling, constant system pressure, make-up water, water quality detection and treatment. -It is generally arranged in the power house, and the volume can be adjusted according to the layout of the power house and the cooling water volume. (Note: in some power plants, it is impossible or difficult to arrange water tanks, so water tanks can be arranged.

2. Circulating cooler

The circulating cooler shall be easy to install and maintain; the cooling effect, service life, stiffness requirements, river water quality and corrosion allowance of the cooler shall be considered in the selection of pipe materials. Anti corrosion and anti rust can be applied with low thermal resistance anti rust coating, zinc spraying and other methods. Inspection, water pressure and water resistance tests shall be carried out before delivery. Under the normal water quality condition, there is no scaling and microorganism growing in the circulating cooler, and the circulating water is not deteriorated.

3. Water supply pump

The pump flow is determined according to the cooling water flow required by the main equipment; the head of the pump is selected according to the loss along the whole system, local loss and the installation elevation difference of all equipment in the whole system. The control of water pump can be selected according to the automation requirements of power station.