CITC-EC DESIGN OF WSN OF SCADA FORWIND POWER PLANT CHAPTER 1 INTRODUCTION Wind energy is one of the new and renewable resources that have the most favorable development prospect, which can replace many one-off resources in some uses, The wind power generating technology is made more and more attentions [1]. Because wind powerplants are mostly in the remote districts, deployed dispersedly, their running state monitorbecome diffic ult. Furth ermore, wind energy's random and seasonal charac teristi c will possibly cause the electric power system to be unstable. Along with the wind plants’ scale expan sion, the wind power genera tion also makes more and more unst able influence on the electric network. The overseas research indicates that if the wind power generation capacity does not surpa ss 10% of the ele ctr ic net wor k's capacity, the wind powergenerating system has little effect on the electric network’s operation [2]. Otherwise, whether the electric power system is safely steadily operating becomes the topic that must be studied. SCADA system for the wind plant is the process control and schedule system of wind power generation. It can realize the automatic surveillance of wind speed, wind direction, the long-dist anc e online dia gno sis and con trol of wind gen erat or, whi ch provides safe gua rd for saf e and effe cti ve run nin g of win d power pla nt [3] . Wir ele ss Sen sorNetworks (WSN) is a novel distributed data processing system, which is developed with the adva nc ement of MEMS, sens in g, co mp ut in g and wi rele ss commun ic at ion tech nol ogi es [4, 5]. WSN has the adv ant age of dis trib ute d inf ormatio n pro ces sin g, covering broadly, and long-distance monitoring. WSN is applied to the wind power plant SCADA sys tem in thi s pap er, whi ch can real ize the effi cie nt, conven ien t, reli abl e surveillance for the wind power plant. Page | 1
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A wind farm is a group of wind turbines in the same location used for production of electric power. Individual turbines are interconnected with a medium voltage (usually
34.5 kV) power collection system and communications network. At a substation , this
medium-voltage electrical current is increased in voltage with a transformer for
connection to the high voltage transmission system.
A large wind farm may consist of a few dozen to several hundred individual wind
turbines, and cover an extended area of hundreds of square miles, but the land between
the turbines may be used for agricultural or other purposes. A wind farm may be located
off-shore to take advantage of strong winds blowing over the surface of an ocean or lake.
2.1 FACTORS CONSIDERED WHILE DESIGNING WIND FARMS
A. LOCATION
A quantity called the Wind Power Density (WPD) is used to select locations for wind
energy development. The WPD is a calculation relating to the effective force of the wind
at a particular location, frequently expressed in term of the elevation above ground level
over a period of time. It takes into account velocity and mass. Color-coded maps are
prepared for a particular area describing, for example, "Mean Annual Power Density, at
50 Meters." The results of the above calculation are used in an index developed by the
National Renewable Energy Lab and referred to as "NREL CLASS." The larger the WPD
calculation the higher it is rated by class. [5]
Wind farm siting can be highly controversial, particularly when sites are picturesque or
environmentally sensitive. Related factors may include having substantial bird life, or
requiring roads to be built through pristine areas. The areas where wind farms are built
are generally non-residential, due to noise concerns and setback requirements.
Access to the power grid is also a factor. The further from the power grid, the more
transmission lines will be needed to span from the farm directly to the power grid.
Alternatively, transformers will have to be built on the premises, depending upon the
As a general rule, wind generators are practical if wind speed is 10 mph (16 km/h or
4.5 m/s) or greater. An ideal location would have a near constant flow of non-turbulent
wind throughout the year, with a minimum likelihood of sudden powerful bursts of wind.An important factor of turbine siting is also access to local demand
or transmission capacity.Usually sites are preselected on basis of a wind atlas , and
validated with wind measurements. Meteorological wind data alone is usually not
sufficient for accurate siting of a large wind power project. Collection of site specific data
for wind speed and direction is crucial to determining site potential. [6] Local winds are
often monitored for a year or more, and detailed wind maps constructed before wind
generators are installed.To collect wind data, a meteorological tower is installed with instruments at various
heights along the tower. All towers include anemometers to determine the wind speed and
wind vanes to determine the direction. The towers generally vary in height from 30 to
60 meters. The towers primarily are guyed steel-pipe structures which are used for one to
two years to collect data and then are disassembled and removed. Data is collected by a
data-logging device, which stores and transmits data for analysis. The siting of turbines
during installation (a process known as micro-siting) because differences of 30 m cannearly double energy production. For smaller installations where such data collection is
too expensive or time consuming, the normal way that developers prospect for wind-
power sites is to look for trees or vegetation that are permanently "cast" or deformed by
the prevailing winds. Another way is to use a wind-speed survey map or historical data
from a nearby meteorological station, although these methods are less reliable.
ALTITUDEThe wind blows faster at higher altitudes because of the reduced influence of drag. The
increase in velocity with altitude is most dramatic near the surface and is affected by
topography, surface roughness, and upwind obstacles such as trees or buildings.
Typically, the increase of wind speeds with increasing height follows a wind profile
power law , which predicts that wind speed rises proportionally to the seventh root of
altitude. Doubling the altitude of a turbine, then, increases the expected wind speeds by
The "wind park effect" refers to the loss of output due to mutual interference among
turbines. Wind farms have many turbines, and each extracts some of the energy of the
wind. Where land area is sufficient, turbines are spaced three to five rotor diameters apart perpendicular to the prevailing wind, and five to ten rotor diameters apart in the direction
of the prevailing wind, to minimize efficiency loss. The loss can be as low as 2% of the
combined "nameplate" rating of the turbines.
In a large wind park, due to "multifractal" effects among individual rotors, the behavior
deviates significantly from Kolmogorov 's turbulence scaling for individual turbines.
2.2 HOW A WIND POWER TURBINE WORKS
The wind turbine converts the wind’s kinetic energy into electricity. A wind turbine
works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind
turbines use wind to make electricity. The wind turns the blades, which spin a shaft,
which connects to a generator and makes electricity.
2.3 TURBINESThe hub and blades of the wind power unit, or aero generator, are called the turbine (or
rotor). Behind the turbine in the nacelle (engine house) is the rest of the electrical
equipment and machinery (see sketch with cross-section). The nacelle is mounted on a
tower in order to allow the wind to flow freely through the turbine, and because the speed
of the wind increases considerably with the height above ground. In the vast majority of
wind power turbines the nacelle contains a yawing gear system, which ensures that the
turbine automatically faces into the wind. The blades slow the wind down and recover
part of its kinetic energy. The turbine on the wind power turbines at Horns Rev 1 (Horns
Reef Offshore Wind Park 1) is 80 meters in diameter with a slewing area or sweep of
5,024 sq.m, in other words the size of a football pitch. The mass of air sweeping through
the slewing area every second at a wind speed of 10 m/s amounts to about 70 tones.
That’s the equivalent of two fully loaded tankers.
The blades are made from composite material, which makes for a durable design. The
turbine blades have an integral, sophisticated lightning protection system, which offers
A wireless sensor network (WSN) consists of spatially distributed autonomous sensors to
cooperatively monitor physical or environmental conditions, such
as temperature, sound , vibration, pressure, motion or pollutants. The development of
wireless sensor networks was motivated by military applications such as battlefield
surveillance and are now used in many industrial and civilian application areas, including
industrial process monitoring and control, machine health monitoring, environment andhabitat monitoring, healthcare applications, home automation , and traffic control.
In addition to one or more sensors, each node in a sensor network is typically equipped
with a radio transceiver or other wireless communications device, a
small microcontroller , and an energy source, usually a battery . A sensor node might vary
in size from that of a shoebox down to the size of a grain of dust although functioning
"motes" of genuine microscopic dimensions have yet to be created. The cost of sensor
nodes is similarly variable, ranging from hundreds of dollars to a few pennies, depending
on the size of the sensor network and the complexity required of individual sensor
nodes.Size and cost constraints on sensor nodes result in corresponding constraints on
resources such as energy, memory, computational speed and bandwidth.
A sensor network normally constitutes a wireless ad-hoc network, meaning that each
sensor supports a multi- hop routing algorithm where nodes function as forwarders,
relaying data packets to a base station. In computer science and telecommunications,
The book is organized into six parts starting with basic concepts and energy efficient
hardware design principles. The second part addresses networking protocols for sensor
networks and describes medium access control, routing and transport protocols. In
addition to networking, data management is an important challenge given the high
volumes of data that are generated by sensor nodes. Part III is on data storage and
manipulation in sensor networks, and part IV deals with security protocols andmechanisms for wireless sensor networks. Sensor network localization systems and
The use of wind power to generate energy is growing very quickly. However, as we havenoted previously, there are a number of challenges facing wind farms. Wind Turbines are
WIND POWER PLANTto take a number of actions such as the scheduling of maintenance, the reconfiguration of
certain operations or the emergency shutdown of the equipment.
In addition to measuring wind speed, WSNs can be used to measure other characteristics
of the physical environment including temperature, humidity, rainfall and light. WSNs
can also be used to provide identifications for individual turbines and farms and their data
can be fused with Web 2.0 presentation technologies to provide real-time identification of
a wind farm, its turbines and the conditions of same. Using 3G, broadband, wireless or
satellite communications, data can be transferred from the remote locations in which wind
farms typically reside.
The Vertoda Framework can capture data from WSNs and transform this data intomeaningful and timely information. Using this information, wind farms can reduce
maintenance costs, improve operational efficiencies and more accurately measure their
revenues.
5.1 SCADA SYSTEM FOR WIND POWER PLANT
Wind energy is the low density energy, and has the instability and the random
characteristic [6]. So, we must use the wind power resource fully, improve the wind
energy usage efficiency, safeguard the wind generator output nearby the rated value,
reduces the output fluctuation, realize the wind power plant running efficiently and
economically. SCADA in the wind power system, can guarantee system information
integrality, grasp the wind power systems’ operation condition exactly, quicken the
increase production and the maintenance decision-making, enhance production efficiency,
and help correctly diagnoses the system failure condition fast[7,8]. Considering the wind
power plant special demands, the SCADA system should have many functions, such as
data acquisition and processing, systems control and adjustment, the operational factors
count and production management, safe operation surveillance and fault warning and
system fault diagnosis and redundancy cut[9,10]. Furthermore, it can compute the total
power of wind generators, transmitted power loss analysis. We can forecast wind power
generation overall output tendency by the real-time data computation, and arrange the
WIND POWER PLANTWireless Sensor Networks (WSN) is a novel technology, which is developed with the
advancement of micro-electronic, data processing, computing, and wireless
communication technology[11,12]. The main goal of WSN is to perform distributed
sensing tasks especially for applications such as environmental monitoring, smart spaces,medical systems and etc. WSN is made up of a large number of sensor nodes, which
consist of sensor, data processing, power provision and communicating modules[13]. The
node architecture is shown in Fig.1.
Figure 4 : Node Architecture of Wireless Sensor Network
The sensor nodes, which are capable of sensing, processing, wireless communication, are
deployed in the sensor field, picking up detecting data by all kinds of sensors, processing
in the data processing module, and transmitting data to the sink node, then to monitor
center for multi-users. The network architecture is shown in Fig.2. Though the individual
node has limited capabilities, WSN which typically has hundreds to thousands of nodes is
capable of achieving a large task through the cooperation of these nodes[14]. As a
distributed information processing system, WSN has much merits, such as credible
measure precision, wider coverage, and remote control. It has become one of the research
Sensor nodes, located on the top of wind power generator, not only gather the real-time
information of wind power generators, but transmit data to the sink node. In WirelessSensor Network, excessive use of node to transmit can makenode energy consume
quickly, shorten network lifetime and cause communication congestion, which affect the
reliability of the SCADA system. In order to balance node energy consumption, we select
route node according to its energy consumption, which reduces the usage frequency of
routes, balances nodes’ energy consumption, prolongs the lifetime of WSN. In this paper,
we adopt IDD-PC based on energy comparison to transmit detecting data, according to
distance between nodes, node energy consumption, which consults the shortest routealgorithm in the 15th reference paper [15]. IDD-PC (Improved Directed Diffusion on
Power Compare), is the route algorithm which improves the directed diffuse algorithm. It
sets up the route from sensor node to sink node according to distance and energy
consumption.
IDD-PC Algorithm as follows:
Step.1: Sink node floods the detecting task to all sensor nodes N(i)(i=1,2,……,n).
Step.2: Each sensor node sets up its superior neighboring nodes’ energy information
table. It is shown in table I as follows.
Table 1 : Energy Information of Superior Neighboring Node
NID(i) denotes the superior neighboring nodes of node i,
WIND POWER PLANTREI(i,j) denotes the remainder energy of its superior neighboring node j, L(i,j) denotes the
distance between node I and node j.
Step.3: Route setup. Suppose time threshold is T, and distance threshold is L=VT, V isthe electromagnetic wave transmission speed. When node i is a route node, we select the
node that the remainder energy is most among its neighboring nodes as its next route
node, that is j=arg max{ SRI(i,j)}. As shown in Fig.6. Firstly, the sink node floods the
task to all sensor nodes, as shown in Fig.6 (a). Then, each node set up its remainder
energy information table. Secondly, the optimal route is set up from source nodes to sink
node according to distance and remainder energy. As shown in Fig.6(b), in time t,
regarding node 14, if L(12,14)<VT , L(13,14)<VT , L(i,j) denotes the distance betweennode i and node j. Either node 12 or node 13 is selected as the next route node, which has
the most remainder energy. Here suppose REI(14,12) < REI(14,13) so node 13 is the
next route node of node 14. Likewise, other sensor nodes select their optimal neighboring
The software design of WSN includes sensor node and sink node software design.
1) Sensor Node Software Design: Assembly and C# is adopted as the main developmentlanguages in sensor node software design. The main function of sensor nodes is detecting
wind driven generator running information, such as wind speed, wind direction,
transferred electric power information and etc. The software comprises running status
detecting module, wireless route setup module and wireless communication module.
Software flow chart of sensor node is in Fig.7.
2) Sink Node Software Design: The sink node software mainly completes the function of
receiving data which the sensor nodes transmit, and then transmit to the monitoring center
after processing. Considering the sink node must carry out the massive real-time data
processing, complex TCP/IP task scheduling and the management demand, the embedded
operating system uses multi-duty real-time kernel uC/OS-II , which source code is
transplantable, public and may cut out . The major part source code is compiled with
ANSI C. The software code has not high request for the processor and resources,has good
readable and transplantable performance. As the open characteristic of uC/OS- , the
user is easy to develop their own application programme on uC/OS- , which is suitable
for the network application and the small embedded system's development specially.
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Power Plant[J].Automation of Electric Power Systems, 2006,30(17):89-93.
[4]AKYILDIZ I F, SU W, SANKARASUBRAMANIAM Y, et al . Wireless Sensor
[14] LIN R Z, WANG Z, et al. Wireless Sensor Networks Solutions for Real Time
Monitoring of Nuclear Power Plant[J]. Proceedings of the 5t World Congress onIntelligent Control and Automation, June 15-19,2004,Hangzhou, P. R. China.
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diffusion[J].Computer Engineering and Design, 2007,28(1):90-93.
[16]Gold smith A J, Wicker S B . Design Challenges for Energy Constrained Ad hoc