Large electric generator internal cooling water microcirculation slow release controlling method and monitoring system

Abstract

The invention discloses a slow-release control method and a monitoring system for the internal cooling water microcirculation of a large-scale generator, which are suitable for use in large-scale generator sets of thermal power, nuclear power and hydropower plants. The method is: when the pH value and conductivity of the cold water in the circulation system are measured to be less than a certain value, the inlet and outlet valves of the small mixed bed are opened, so that part of the internal cold water passes through the bypass circulation system for microcirculation, and the trace amount of the small mixed bed is slowly released. Alkaline substances are brought into the inner cooling water tank to control the pH value and conductivity of the inner cooling water within a certain range; when the pH value and conductivity of the inner cooling water in the circulation system reach a certain value, close the inlet and outlet valves of the small mixed bed; When a certain value is reached, open the drain valve of the inner cooling water tank and the replenishment valve of the desalinated water at the same time until the conductivity of the inner cooling water is less than a certain value. Its alkaline substances are composed of negative and positive resins; its supporting monitoring system is composed of internal cooling water quality monitoring and control system, bypass circulation treatment control system and water replenishment and sewage discharge control system. The invention can effectively prevent the deterioration of the internal cooling water quality and inhibit the corrosion of the hollow copper wire of the generator, so as to ensure the safe and economical operation of the generator.

Description

Technical field: [0001] The invention relates to a microcirculation slow-release control method and a monitoring system for cold water in a large generator, and belongs to the technical field of electrical engineering. Background technique: [0002] The stator windings of large generators such as thermal power plants, nuclear power plant steam turbine generators, hydroelectric power plant hydro-generators and the rotor windings of dual water internal cooling generators adopt high-purity water circulating cooling, and the cooling water quality is polluted by oxygen and carbon dioxide in the air. Deterioration, resulting in corrosion of the hollow copper wire. At present, the commonly adopted protection method is to seal the cooling water tank with nitrogen or hydrogen and add corrosion inhibitors such as MBT or BTA and its derivatives to the internal cooling water (see "Generator Cooling Medium", Water Power Press, November 1995 Edition). Since the air tightness of the internal co...

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Problems solved by technology

Since the airtightness of the internal cooling water circulation system and its supply water pipeline is difficult to be guaranteed, the method of gas sealing with nitrogen or hydrogen is rarely used in engineering practice, and the use of hydrogen has potential safety hazards

The method of adding corrosion inhibitors such as BTA is more commonly used, but there are still many shortcomings. The main problems are: 1. The residual concentration in the system is detected by manual addition and manual sampling analysis; 2. The corrosion inhibitor used is a weak electrolyte , there is no characteristic parameter suitable for on-line detection, and it is not suitable for automatic control; 3. The corrosion inhibitor used is an organic substance containing a benzene ring structure, and the protective film formed has a large thermal resistance, which is not conducive to the cooling of the copper wire winding of the generator Heat dissipation; 4. It is often necessary to manually add agents to repair the protective film

In fact, at present, many power plants have not adopted any adjustment and control measures for the internal cooling water of the generator. The pH value of the internal cooling water has been low for a long time, and the Cu content often exceeds the standard. Therefore, the method of frequent water changes is used to maintain the conductivity. This method has neither Solve the corrosion problem of copper wires, and at the same time waste a lot of high-purity water

The water quality of the internal cooling water has become one of the potential safety hazards of the generator and limits the output of the generator

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