关于水力发电厂直流系统的故障分析

在水力发电厂运营管理中，要想查找直流接地故障，首先要对接地的位置进行确定，也就是接地故障定位。直流接地在很多情况下有多个点，而不是只有一个点，很少会有真正通过一个金属点去接地的直流电源。很多时候会因为尘土粘贴、空气潮湿、电缆破损或者设备某些部分的绝缘降低，或者一些其它因素所造成。绝大部分的接地故障会随着环境的变化而变化，有很高的不稳定性，因此要想在现场对直流接地进行查找并不容易。

Drillhole high-pressure packer permeability test for underground powerhouse in Pushihe pumped storage hydro-plant

Usually the water head of the pumped storage hydro-plant is high, generally up to 400-500 m, therefore the rock mass under the high-pressure bifurcation pipe have to bear as high as millions Pascal water pressure, in according with the requirements of high water head pumped storage hydro-plant should be 1.2 times of the water head special high-pressure packer permeability test compared with normal to test the permeability of rock and rock cleavage pressure value. The test results on the choice of design options often play a decisive role. Based on the engineering practice, the authors studied the drillhole high-pressure packer permeability test in the pumped storage hydro-plant's underground powerhouse, by the analysis of test results, this article offers a demonstration of the deformation of rock fracture witch under building in the condition of high-pressure water head, it provides a more detailed engineering geological background.

Current State of High 120 m Concrete Dam Bratsk Hydroelectric Power Plant

The research object was high 120 m concrete gravity dam of the Angara Bratsk hydroelectric power plant. The state of the concrete dam is estimated based on the results of continuous supervision performed by site personnel as well as periodic monitoring. According to the classification of the interrelations in the system ＂concrete-environment＂, there were selected some important parts of dams and a comprehensive analysis of concrete was executed on these parts. Concerning the complex research of concrete, a combination of full-scale tests with core-sampling has been proposed. Core samples tests had an object to study the deep concrete layers and to determine the specific indicators such as strength, density, porosity, comparative diameter of capillary pores, CaO content in cement stone and others. Obtained findings and recommended criteria can be applied when selecting technologies for constructing dams that guarantee their durability in the north.

Characterization of the Constructions Materials Used in the Hydroelectric Power Plants in the Sedano＇s Valley, Burgos （Spain）

Small hydropower plants for electricity generation were first built in Spain in the early 1880s. The Spanish peninsula is characterized by its rugged landscape, fast flowing rivers and steep gradients. A clear example of this is the remarkable area of the upper Ebro river basin where powerful water flows are found that are ideal for electricity generation. Between 1900 and 1930, the river Ebro was a major source of energy for industrial areas such as Alava, Vizcaya, Vitoria, Miranda de Ebro, Burgos and La Rioja. Between 1951-1965, the use of these small hydropower plants declined due to the construction of alternatives by industrialists in the Basque Country, which in most cases led to their deterioration. They were rescued in the late twentieth century, thanks to private sector initiatives which funded their rehabilitation. This study examines two small-scale hydraulic power plants in the province of Burgos at Medina de Pomar and at Quintanilla Escalada; both buildings were used for generating electricity and had living quarters for the workers and now represent historic architectonic and industrial heritage. The study documents their architectonic features and the restoration processes that have permitted one of them to remain in operation up until the present day.

Electricity Generation in Turkey by Geothermal Energy Resources

Electricity generation generally is made in thermal, hydro, geothermal power plants and windfarms/windparks. Because of some advantages such as renewability, low-cost, clean, safe and naturality geothermal and wind energy will have been electricity generation source in the near future. Turkey has hot water springs suitable for electricity generation between 130-242 ~C with natural vapor and hydrothermal alterations in connection with grabens limited to active faults and diffuse young volcanism in Western Anatolia Region. Other renewable energy and electricity generation resource is wind energy. In Turkey electricity generation is made by windfarms/windparks. These parks/farms are generated 1,414.55 MW electricity. The year 2010 electricity general total installed capacity in Turkey is about 49,524.1 MW. According to the total installed capacity, thermal power plants have 65.18%, hydro power plants have 31.97%, geothermal power plants and wind farms have 2.85%. Electricity generation generally was obtained from 15 thermal power plants. In this study high temperature geothermal fields and windparks/windfarms in Turkey which are suitable for electricity generation potential were investigated.

Stability Study of a Mixed Islanded Power Network

This paper presents the modelling, simulation and analysis of the dynamic behaviour of a mixed power network of 2.78 GW including hydro, thermal and wind power plants. The modelling of each power plant is described. The set of parameters of the turbine speed governor of the hydroelectric power plant is determined with a specific identification procedure to achieve stable operation for different cases such as interconnected, isolated or islanded operation. The analysis of the stability of the entire mixed islanded power plant is investigated through time domain simulations for different sets of controllers parameters and for different disturbances （load rejection and turbulent wind speed profile）.

Towards a Sustainable Development of Small Hydropower Plants, from Valley of Sperchios River to Mount Olympus

The mountainous region of Fthia, identified with the Valley of Sperchios River, in Central Greece, is rich in small watercourses and generously blessed with water and abundant water falls. The geographical configuration of Olympus and Fthia＇s mounts and the hydraulic singularities of drained lakes Askouris in Olympus, favour the installation of series of sustainable small hydroelectric plants. The present action consists of a serious effort towards the systematic sustainable small hydropower exploitation of Fthia＇s and Olympus hydraulic potential, including the Archimedean hydropower perspectives of Sperchios River.

Innovative Control Strategy for Islanded Small Hydro Power Plant

In many developing countries, there are regions where the electrical grid is weak or nonexistent. However, in these areas, large amounts of distributed energy sources, such as hydro, are often available and could be suitably exploited. To this aim, the low head hydro power plants can play a significant role. In fact, recent technological advances in mini-hydro turbines and decreasing costs of static electricity conversion devices enable to realize suitable power plants for an efficient and profitable exploitation of these sites. One of the major challenges is the integration of the above-mentioned power plants into autonomous electrical systems, islanded and/or disconnectable from the main distribution network. In this paper, an innovative control strategy for a low head hydro power plant supplying users in small clusters of villages is proposed.

Monitoring the Technical Condition of Dams of Hydroelectric Power Plants with an Automated Monitoring and Earthquake Registration System

An approach is described that has been developed for auxiliary monitoring of technical condition of hydropower plant dams. It is based on analysis of changes in dynamic characteristics of dams obtained by an automated monitoring and earthquake registration system that records microseismic vibrations of structures. The configuration of the system as well as the results of seismometric monitoring of the dam of Krasnoyarsk hydroelectric power plant are described. To study behavior of the dam under normal and extreme loads it was proposed to develop a model of the dam with the use of the finite element method.

Profit-Based Optimal Operation of a Head-Dependent Hydroelectric Power Station in the Bilateral Market

Deregulation and liberalization of electric power industry, among other things, has created new requirements for the market participants. The power system engineer, operator, and, in general, the market participants are being faced with requirements for which they do not have adequate training and the proper software tools. In this framework, among others, a pure hydro-generation company has to operate its hydro units, throughout the operating day, trying to fulfill the market clearing schedule or a bilateral contract, and modify the program in the intra-day energy markets if necessary （or more suitable） as real-time operation is getting closer. In this scenario the objective is to maximize the hydroelectric power plant profit from selling energy in the spot market or by means of bilateral contracts. In this paper the optimal operation of a head-dependent hydroelectric power station in bilateral market-short-term hourly hydro resource scheduling for energy is obtained.

Advance Electronic Load Controller for Micro Hydro Power Plant

Most of the MHP （micro hydro power） plants use ELC （electronic load controller） for speed control. Various types of ELC have been developed so far. A dummy ballast load is connected across each phase of generator terminals and ELC controls the power consumed by the ballast load to result in constant speed operation. The ELC developed so far uses thyristor switches in each phase to control ballast load power. The ELC senses the system frequency and comparing it with reference frequency, it generates a common value of firing angle for all three thyristor pairs of each phase. The performance of such ELC is not perfect for unbalanced consumers load connected in each phase, which overloads the generator. This paper presents an advanced type of ELC which senses frequency as well as consumer＇s load current of each phase and fires the thyristor pairs with different value of firing angles for different phases. This solves the problem of overloading of the generator with unbalanced consumer＇s load. Simutink model is developed to perform transient analysis of the proposed scheme and the prototype of hardware is also fabricated. The simulation results and experimental results are presented.

Voluntary Carbon Market in Turkey

Nowadays, global warming is a major environmental concern. Climate change is dominating the environmental agendas, especially in developed countries at first, but by now, around the world. Several initiatives have been undertaken to reduce the effect of increasing atmospheric GHGs （greenhouse gasses） concentrations. Emerging carbon emissions trade under the Kyoto Protocol serves to market the carbon quotas among the countries, thus, it helps to increase their level of GNP （gross national product）. Emissions trade is being performed in the voluntary and compliant markets. Increasing interest in emission trade emerged carbon and energy exchanges markets in the world. Turkey is located in the voluntary markets, and organizations buying carbon offset credits in order to achieve their voluntary emission reduction goals. GS （gold standard） and VCS （verified carbon standard） are mainly being used to finance renewable energy projects in Turkey. In the GS, there are 209 projects which are currently in the approval process or in the application, such as wind energy, hydroelectric power plant and biogas energy production. In addition to these, in the VCS, there are 61 projects which are mainly energy industries, in the approval process or in the application. Most environmental issues require long-term plans which include international cooperation, especially climate change. The Kyoto Protocol marks the beginning of a new era to combat global climate change. Voluntary markets are very popular and forty percent of the total global GS projects and around nine percent of VCS projects are implemented in Turkey. These projects are initial steps for future implementations of compliant markets in Turkey.

Influence of Excitation System＇s Parameters to the Power System Stability

Excitation system is one of the significant elements affecting the dynamic performance of electric power systems. The power engineering as area of science and industry is subjected to rapid modernization, which is caused by technological progress. However, not all elements of the power system are developing simultaneously. The old type of elements sometimes is sufficient to adapt old system to the new operational conditions. The work developed and proposed in this paper deals with analysis of possible optimization of synchronous generator＇s excitation system. Authors examined influence of excitation system＇s parameters to the dynamics of transient processes in the power system. Authors investigated optimal parameters of excitation system of the Kegums hydro power plant. For optimization of parameters objective functions were used. The problem of the mutual influence of excitation systems of neighbor power plants was investigated. Investigation of transient processes using developed model proved that optimization of excitation parameters improves efficiency of regulation of excitation system, damping of active power oscillation and in some cases can prevent out-of-step condition.