RU2704352C1 - Method of restoration of insulation resistance of current conductors of working equipment of power plants - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to methods and devices for drying air used for recovery of resistance of electric insulation, and can be used both in power engineering, in particular for conservation of steam turbines and boilers, and in other industries, for example in communication, in transport, in computer industry, etc. Method of restoration of insulation resistance of current conductors of working equipment of power plants consists in reduction of humidity of current conductors and their environment by supply of dry air to the current conductors. Air drying is performed in drying rotor, for this purpose air is passed through working channels of drying rotor, coated with composite adsorption composition, then, dry air is supplied via ducts to current conductors and moist air is drained from current conductors through check valves. Supply and distribution of dried air are controlled with gates by signals from air humidity sensors installed at the outlet of moist air. Dehydration rotor and dry air supply are switched on automatically at power unit or power plant power plant shutdown, and dehumidifying rotor and dry air supply are switched off at fire signaling.

EFFECT: higher efficiency of drying insulation of current conductors of power plants, automation of drying processes, simplification and cheapening of drying processes, increased intervals between process maintenance of equipment, as well as considerable reduction of starting time of turbine generator.

5 cl, 9 dwg

Description

The invention relates to methods and devices for drying air used to restore electrical insulation resistance, and can find application both in the energy sector, in particular for the conservation of steam turbines and boilers, and in other industries, for example, in communications, in transport, in the computer industry, and etc.

Long-term experience in operating electrical equipment of power plants shows that high humidity and penetration of process water and steam into mechanisms can cause a decrease in insulation resistance, failures and malfunctions in the operation of electrical equipment. This happens on any electrical equipment, ranging from 0.4 kV electrical distribution assemblies to high-voltage equipment, windings of stators and rotors of generators, transformer windings, current leads.

Known methods and devices currently used to restore insulation resistance lead to its premature aging and, as a result, a sharp decrease in the life of the equipment, as well as to high energy costs.

So, for example, from SU 348834 from 08.23.1972, a method of drying insulating and structural materials of a freon sealed refrigeration unit is known, which consists in blowing a moisture-absorbing substance through the unit, an oil-freon mixture, which is continuously dried in an adsorption filter, and the degree of drying is controlled by a humidity indicator.

The disadvantages of the known technical solutions are the limited scope, technological imperfection and, as a consequence, a rather low efficiency.

A dehumidifier is also known (see SU 1030000 dated 07/23/1983), including a drum rotating on the axis with sorbent sections in it, inlet and outlet ducts, a fixing device with springs and supporting mechanisms mounted on the axis connected to the ducts. The design of the dehumidifier allows you to drain and clean the air, which can then be supplied to both residential and industrial premises.

As in the previous case, the disadvantages of the analogue are the limited scope, technological imperfection and, as a consequence, a rather low efficiency.

The closest technical solution can be considered a method of maintaining cables under constant overpressure of dried air and a device for its implementation (see RU 2098903 from 12/10/1997). The disclosed technical solution is used in devices and methods for operating cables in all industries to protect the internal spaces of cables from moisture and chemicals, especially in the electric power industry and communications. It is proposed to contain cables under constant overpressure, supplying compressed air to the system, draining it, controlling the process, controlling the parameters of air pressure in all volumes, at the same time treating the rest of the air, and maintaining overpressure in all volumes, and select parameters and time in a certain way conducting method operations. To implement the method, an appropriate device is proposed.

Despite the increase in operational performance and a decrease in total costs, the lack of prototype can be attributed to the lack of efficiency of drainage of electrical insulation and the lack of automation of drainage processes.

The technical problem to which the invention is directed is to create a simple and effective method of drainage of electrical insulation, providing restoration of its resistance and increasing its service life.

The technical result achieved in this case is to increase the drainage insulation efficiency of the current conductors of power equipment of power plants, automate drainage processes, simplify and reduce the cost of drainage processes, increase the intervals between technological maintenance of equipment, and also significantly reduce the start-up time of a turbogenerator.

The technical result is achieved due to the fact that the method of restoring the insulation resistance of the conductors of the working equipment of power plants is carried out by reducing the humidity of the conductors and their environment by supplying dried air to the casing of the conductors.

The new according to the invention is that the air is drained in the drying rotor, and air is passed through the working channels of the drying rotor coated with a composite adsorption composition, then the dried air is supplied to the current leads through the air ducts and the humid air is removed from the current leads through the check valves, at the same time, the supply and distribution of drained air are controlled by the shutters according to signals from air humidity sensors installed at the outlet of moist air, moreover, nical include bilge rotor and feeding dried air at stop power plant or a power plant and disconnected bilge rotor and feeding dried air at a fire alarm.

Drying the air by means of a rotor of the proposed design, the working channels of which are coated with a composite adsorption composition, allows to increase the drainage efficiency, reduce the cost of the drainage process and increase the intervals between technological maintenance of the equipment due to the use of composite adsorption coating, which has a significantly longer service life, recovers faster and provides more effective dehumidification of air in comparison with silica gel and other granular adsorbents, using we are currently for these purposes.

The implementation of the removal of moist air through the check valves and the regulation of the supply and distribution of dried air by the dampers according to signals from air humidity sensors provides automation of the process of restoring insulation resistance, which, together with the automatic modes of supplying dried air when the power unit or power plant is stopped and the supply of dried air fire alarm ensures safety and maximum process efficiency restoration of insulation resistance while reducing energy consumption, reducing cost and simplifying process technology.

In the future, the invention will be disclosed in detail with reference to graphic materials, where:

- in FIG. 1 - schematic design and principle of operation of the drying rotor;

- in FIG. 2 is a schematic flow diagram of the drying of conductors with a VVG type switch (Air Generator Circuit Breaker) and with the placement of a drying unit in the VVG room;

- in FIG. 3 is a schematic flow diagram of the drying of conductors with the placement of a drying installation in the room of the terminals of the turbogenerator in the presence of bushing;

- in FIG. 4 is a schematic flow diagram of the drying of conductors with the placement of the drying installation outside the premises of the conclusions of the turbogenerator in the presence of bushing;

- in FIG. 5 is a schematic flow diagram of the drying of conductors 20 kV with the placement of the drying installation outside the premises of the conclusions of the turbogenerator without bushing;

- in FIG. 6 is a schematic flow diagram of the drying of conductors in a closed circuit;

- in FIG. 7 - change in insulation resistance of conductors 20 kV;

- in FIG. 8 is a flow chart of the preservation by dried air of an air-cooled turbogenerator and a brush-contact apparatus;

- in FIG. 9 is a flow chart of the preservation by dried air of a hydrogen-cooled turbogenerator, pathogen and brush-contact apparatus.

It should be noted that in this application discloses several, but not all embodiments of the invention.

The inventive method of restoring the insulation resistance of the conductors of the working equipment of power plants is to reduce the humidity of the conductors and their environment by supplying dried air to the conductors.

It is proposed to dehumidify the air by means of an adsorption air-drying plant (ОУ - drying plant), the main element of which is a drying (moisture-absorbing, adsorption) rotor 1 made in the form of a disk.

The structure of the drying rotor 1 is a narrow parallel air ducts treated with an adsorption composite composition, which has a great ability to attract from the air and retain water vapor.

In the last 10-15 years, in the world practice of producing adsorbing materials, the tendency to use composite sorption-active materials (CSAM) has become increasingly clear. KSAM relate to the materials of the matrix structure, since they usually consist of a plastic base - matrix and inclusion - fillers, available for mixing and subsequent molding. The matrix acts as a binder component of the material, which determines its strength and ductility as a whole under the influence of mechanical, hydraulic and other loads. In the case of CSAM, the role of fillers is played by sorption-active materials (additives may also be present that activate the material or impart specific properties to it). Their composition, structure, dispersion, and content in the composition not only determine the adsorption properties of CSAM, but also affect the strength and stiffness of the material. The advantages and prospects of using CSAM are determined by the fact that they often possess properties that none of the component components possess.

Thus, the application of an adsorption composite composition to the surface of the parallel air channels of the drying rotor 1 makes it possible to increase the efficiency and reduce the cost of the drainage process.

The drying rotor 1 is functionally divided into two sectors - a larger sector 2 for the passage of drained air and a smaller sector 3 for the passage of regeneration air.

The flow of drained air, called the working (process) air, passes through sector 2 and the moisture in the process air is absorbed by the rotor 1. The process air leaves the dryer in the form of dry air and is supplied to the ducts. The supply of dry air to the ducts can be carried out, for example, by means of a pumping device 4.

Due to the slow rotation of the rotor 1, process air always passes through the dry part of the rotor 1, as a result of which a continuous drying process occurs.

The regeneration air stream used to dry the rotor 1 must be preheated in the heating device 5. Passing through the rotor sector 3 in the opposite direction to the process air, this stream removes moisture absorbed by the rotor 1 and leaves the desiccant in the form of moist regeneration air. Wet air regeneration can be removed, for example, by means of an exhaust device 6.

Through the air ducts 7, the dried air is supplied to the conductors - both to the supply power cables, and to electrical appliances and electrical equipment - turbogenerators, transformers, etc.

The connection of ducts to the casing of the conductors can be performed through dielectric inserts.

At the end of each section of the conductor, check valves 8 are installed, through which humid air is removed from the conductors.

To prevent insects and animals from entering the air ducts, the check valves 8 are provided with protective nets.

The regulation of the supply and distribution of dried air is carried out automatically by dampers (not shown) according to signals from sensors (not shown) of air humidity installed at the outlet of moist air. Structural and layout layouts of adjusting air dampers and air humidity sensors depend on specific operating conditions and drained equipment.

Also, depending on the operating conditions and the equipment being drained, the process of draining and reducing the humidity of the conductors and their environment can be carried out both in open and closed circuits.

To ensure the safety and maximum efficiency of the process of restoring insulation resistance, as well as to reduce energy consumption, the adsorption air-drying unit is automatically turned on when the power unit or power plant of the power plant is stopped and turned off when a fire alarm is triggered.

For clarity, the implementation of the proposed method in figures 2-6 schematically shows the basic technological schemes for drying current conductors and various electrical equipment both in open and closed air treatment circuits. The figure 7 presents a graph of changes in insulation resistance of conductors 20 kV when implementing a method of restoring electrical insulation resistance. The presented graph clearly demonstrates the effectiveness of the proposed method. In figures 8 and 9 schematically shows the basic technological scheme of conservation of the dried air turbine generator and other electrical equipment.

Moreover, in the figures, the positions indicated:

1 - rotor;

2 - a larger sector 2 of the rotor 1;

3 - a smaller sector 3 of the rotor 1;

4 - pumping device;

5 - heating device;

6 - exhaust device;

7 - air ducts;

8 - check valves;

9 - drainage unit (OS);

10 - turbogenerator (TG);

11 - power transformer (T);

12 - auxiliary transformer (TSN);

13 - turbine generator housing;

14 - brush-contact apparatus;

15 - pathogen;

16 - gas post.

Thus, the proposed method of drainage of electrical insulation is technically and technologically easy to implement and extremely effective for restoring electrical insulation resistance and increasing its service life, as it provides quick restoration of electrical insulation resistance, does not lead to its aging and premature failure, which allows to increase the intervals between technological equipment maintenance, reduce labor costs and cash costs and significantly reduce the start-up time of the turbogenerator.

Claims (5)

1. The method of restoring insulation resistance of the conductors of the operating equipment of power plants, which consists in reducing the humidity of the conductors and their environment by supplying dried air to the conductors, characterized in that the air is dried in a drying rotor, and air is passed through the working channels of the drying rotor coated with a composite adsorption composition, then through the ducts, dried air is supplied to the conductors and the humid air is removed from the conductors through These valves regulate the supply and distribution of drained air with dampers according to signals from humidity sensors installed at the outlet of moist air, moreover, they automatically turn on the drying rotor and supplying drained air when the power unit or power plant is stopped and shut off the drying rotor and draining air when fire alarm. 2. The method according to p. 1, characterized in that the process of reducing the humidity of the conductors and their environment is carried out according to an open circuit. 3. The method according to p. 1, characterized in that the process of reducing the humidity of the conductors and their environment is carried out in a closed circuit. 4. The method according to p. 1, characterized in that the connection of the ducts to the casings of the conductors is made through dielectric inserts. 5. The method according to p. 1, characterized in that the check valves are installed at the end of each section of the conductor and provide protective nets to prevent the ingress of insects and animals.

Images