How are large, medium, and small power plants divided? According to the current standards, those with an installed capacity of less than 25000 kW are classified as small; Medium sized with an installed capacity of 25000 to 250000 kW; Large scale with an installed capacity greater than 250000 kW.
What is the basic principle of hydroelectric power generation?
Hydroelectric power generation is the use of hydraulic power (with a water head) to drive the rotation of hydraulic machinery (water turbine), converting water energy into mechanical energy. If another type of machinery (generator) is connected to the water turbine to generate electricity as it rotates, then mechanical energy is converted into electrical energy. Hydroelectric power generation, in a sense, is the process of converting the potential energy of water into mechanical energy and then into electrical energy.
What are the development methods of hydraulic resources and the basic types of hydropower stations?
The development methods of hydraulic resources are selected based on concentrated drop, and there are roughly three basic methods: dam type, diversion type, and mixed type. But these three development methods also need to be applicable to certain natural conditions of the river section. Hydroelectric stations built according to different development methods have completely different hub layouts and building compositions, so they are also divided into three basic types: dam type, diversion type, and mixed type.
What standards are used to classify water conservancy and hydropower hub projects and corresponding agricultural, industrial, and residential buildings?
The classification and design standards for water conservancy and hydropower hub projects issued by the former Ministry of Water Resources and Electric Power, SDJ12-78, should be strictly followed, and the classification should be based on the size of the project (total reservoir volume, installed capacity of the power station).
5. What are flow, total runoff, and annual average flow?
Flow refers to the volume of water passing through a river (or hydraulic structure) in a unit of time, expressed in cubic meters per second; The total runoff refers to the sum of the total water flow through the river section within a hydrological year, expressed as 104m3 or 108m3; The average annual flow refers to the average annual flow of a river cross-section calculated based on existing hydrological series.
6. What are the main components of small-scale hydropower hub projects?
It mainly consists of four major parts: water retaining structures (dams), flood discharge structures (spillway or gates), water diversion structures (water diversion channels or tunnels, including surge shafts), and power plant buildings (including tailwater channels and booster stations).
7. What is a runoff hydropower station? What are its characteristics?
A power station without a regulating reservoir is called a runoff type hydropower station. This type of hydropower station is selected for installed capacity based on the average annual flow rate of the river and the possible water head obtained. Unable to operate at full capacity throughout the year with a guarantee rate of 80%., Generally, it only reaches normal operation for about 180 days; During the dry season, the power generation sharply decreases to less than 50%, sometimes even unable to generate electricity. It is constrained by the natural flow of the river, and there is a large amount of abandoned water during the flood season.
8. What is output? How to estimate the output of a hydropower station and calculate its power generation?
In a hydroelectric power plant, the electrical power generated by a hydroelectric generator set is called output, while the output of a certain section of water flow in a river represents the hydroelectric resources of that section. The output of water flow is the water energy per unit time.
N=9．81 QH
In the formula, Q is the flow rate (m3/S); H is the water head (m); N is the output of the hydropower station (W); The efficiency coefficient of a hydroelectric generator.
The approximate formula for the output of small hydropower stations is
N=（6．0～8．0）QH
The formula for annual power generation is
E=N· F
In the formula, N is the average output; T is the annual utilization hours.
9. What is guaranteed output? What is its purpose?
The average output that a hydropower station can produce during a long period of operation, corresponding to the design guarantee rate, is called the guaranteed output of the hydropower station. The guaranteed output of hydropower stations is an important indicator, and it is an important basis for determining the installed capacity of hydropower stations in the planning and design stage.
10. What is the annual utilization hours of installed capacity?
The average full load operation time of a hydroelectric generator set within a year. It is an important indicator for measuring the economic benefits of hydropower stations, and the annual utilization hours of small hydropower stations are required to reach over 3000 hours.
11. What are daily regulation, weekly regulation, annual regulation, and multi-year regulation?
Daily regulation refers to the redistribution of runoff within a day and night, with a regulation cycle of 24 hours. Weekly regulation: The regulation cycle is one week (7 days). Annual regulation: The redistribution of runoff within a year. When water is abandoned during the flood season, only a portion of the excess water stored during the flood season can be regulated, which is called incomplete annual regulation (or seasonal regulation); The runoff regulation that can fully redistribute incoming water within the year according to water usage requirements without the need for water abandonment is called annual regulation. Multiyear regulation: When the reservoir volume is large enough, excess water can be stored in the reservoir for many years, and then the surplus water can be used to make up for the deficit. The annual regulation, which is only used in several dry years, is called multi-year regulation.
12. What is the drop and gradient of a river?
The elevation difference between the water surfaces of the two cross-sections of the utilized river section is called the drop; The elevation difference between the water surfaces of the two cross-sections of the river source and estuary is called the total drop. The drop per unit length is called the slope.
13. What is the precipitation, precipitation duration, precipitation intensity, precipitation area, rainstorm center?
Precipitation is the total amount of water that falls on a certain point or area during a certain period of time, expressed in millimeters. The duration of precipitation refers to the duration of precipitation. Precipitation intensity refers to the amount of precipitation per unit area, expressed in millimeters per hour. Precipitation area refers to the horizontal area covered by precipitation, expressed in km2. The rainstorm center refers to a small local area where rainstorm is concentrated.
14. What is the design guarantee rate for hydropower stations? Annual guarantee rate?
The design guarantee rate of a hydropower station refers to the percentage of the number of normal operating hours during many years of operation compared to the total operating hours; The annual guarantee rate refers to the percentage of years of normal power generation work over the total number of years of operation.
What is the purpose of preparing a design task book?
The purpose of preparing a design task book for small hydropower stations is to determine the basic construction project and serve as the basis for preparing preliminary design documents. It is one of the basic construction procedures and also one of the means for the competent authorities to carry out macroeconomic regulation.
What is the main content of the design task book?
The main content of the design task book includes eight aspects:
It should include all the contents of watershed planning and feasibility study report. It is consistent with the preliminary design, with only differences in the depth of the research problem.
Analyzing and describing the engineering geological and hydrogeological conditions of the construction areas within the watershed, a map collection of 1/500000 (1/200000 or 1/100000) can be carried out, with only a small amount of geological exploration work. Clarify the geological conditions, available depth of bedrock, depth of riverbed cover layer, and major geological issues in the designated design scheme area.
Collect hydrological data, analyze and calculate, and select the main hydrological parameters.
Measurement work. Collect 1/50000 and 1/10000 topographic maps of the building area; 1/1000 to 1/500 topographic map of the factory area at the construction site.
Perform hydrological and runoff regulation calculations. Selection and calculation of various water levels and heads; Short – and long-term electricity and energy balance calculations; Preliminary selection of installed capacity, unit model, and electrical main wiring.
Compare and select the types of hydraulic structures and hub layouts, and conduct hydraulic, structural and stability calculations, as well as engineering quantity calculations.
Economic evaluation analysis, demonstration of the necessity and economic rationality evaluation of engineering construction.
Environmental impact assessment, engineering investment estimation, and engineering implementation plan of the project.
17. What is an engineering investment estimate? Engineering investment estimation and engineering forecast?
Engineering estimate is a technical and economic document that prepares all construction funds required for a project in monetary form. The preliminary design general estimate is an important component of the preliminary design document and the main basis for assessing economic rationality. The approved total budget is recognized by the state as an important indicator of basic construction investment, and is also the basis for preparing basic construction plans and bidding designs. Engineering investment estimation is the investment amount made during the feasibility study stage. The engineering budget is the amount of investment made during the construction phase.
Why do we need to prepare a construction organization design?
Construction organization design is one of the main basis for preparing engineering estimates. It is the most basic task to calculate unit prices based on various conditions such as the determined construction method, transportation distance, and construction plan, and to compile a unit engineering estimate table.
19. What is the main content of construction organization design?
The main content of construction organization design is the overall construction layout, construction progress, construction diversion, interception plan, external transportation, sources of building materials, construction plan and construction methods, etc.
How many design stages are there in the current water conservancy and hydropower basic construction projects?
According to the requirements of the Ministry of Water Resources, there should be watershed planning; Project proposal; Feasibility study; Preliminary design; Tender design; Six stages including construction drawing design.
21. What are the main economic indicators of hydropower stations?
Unit kilowatt investment is the investment required per kilowatt of installed capacity.
Unit electricity investment refers to the investment required per kilowatt hour of electricity.
The cost of electricity is the fee paid per kilowatt hour of electricity.
The annual utilization hours of installed capacity are a measure of the degree of utilization of hydropower station equipment.
The price of electricity is the price per kilowatt hour of electricity sold to the grid.
How to calculate the main economic indicators of hydropower stations?
The main economic indicators of hydropower stations are calculated using the following formula:
Unit kilowatt investment=total investment in hydropower station construction/total installed capacity of hydropower station
Unit electricity investment=total investment in hydropower station construction/average annual power generation of hydropower stations
Annual utilization hours of installed capacity=average annual power generation/total installed capacity
Post time: Jun-24-2024
