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Wind Power Integration to the Transmission Grid: The
Egyptian Perspective
Article in Energy & Environment · January 2015
DOI: 10.1260/0958-305X.26.1-2.143
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143
WIND POWER INTEGRATION TO THE TRANSMISSION
GRID: THE EGYPTIAN PERSPECTIVE
Fathalla M. L. Shalaby1, Abdelraheem Helmi1, Dalal Helmi1, Laila Georgy2,
Mohamed El-Khayat2 and Mohamed Ibrahiem2
1
Egyptian Electricity Transmission Company (EETC), Abbassia, Ramsis st. extension, Cairo,
Egypt. Tel.: (+202) 22618579 – 26843824, Mob. +2 0122 2730828, Fax: (+202) 22616486
eetc_chairman@yahoo.com, abdelraheem52@yahoo.com, dalalhelmi@hotmail.com
2
New and Renewable Energy Authority (NREA), Ibrahim Abu El-Nagaa St., Hay El- Zohour,
Nasr City,Cairo, Egypt. Tel. +202 227 13 176, Mob. +2 01228090810, Fax: +202 227 17 173
lailag_fathy@yahoo.com, mohamed.elkhayat@yahoo.com, m.nrea2010@yahoo.com
Summary
The Government of Egypt has recognized that the availability of reliable power supply
is essential for economic and social prosperity and human development as well
as for attracting private sector investments in the country. Egyptian Economic reform
and growth have triggered a rapid increase in electricity demand. Peak load growth
rate averaged 7 % p.a. in 2005-2008 and reached as high as 12% in 2008/09. In
response to the rapid growth in demand, the supply capacity has expanded through an
ambitious power sector investment program that has been under implementation since
2002. The Government’s new energy strategy is aiming to increase the share of
renewable energy to 20 % by the year 2020. 12% of this value, i.e 7200 MW, is from
wind resources.
The complexity of the interconnection of wind farms to the power grid stems from
the fact that wind energy is rather unstable and available only during certain hours of
the day. By its nature the wind power generation may drop suddenly. To keep the grid
operation stable, there is a need to ensure that other power generation sources are
available to compensate for the drop. Another common characteristic of the wind
farms is that they are located somewhat remote from the power grid. Therefore, the
utility has to ensure the sufficiency of power transmission capacity. A rather unique
feature of wind power in Egypt is that most of the wind resources are concentrated in
the Gulf of Suez and Eastern and Western bank of Nile River areas. This raises the
additional issue of the impact on the system when large amount of wind power are
interconnected at certain points of the network and not distributed over along the
country. The effects of having 3000 MW in Gulf of Suez and 4200 MW at Western
Nile River areas depend very much on the local wind climate and the typical hour- tohour load curve (electricity demand).
Some important issues needed to be considered are therefore: how should wind
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Energy & Environment · Vol. 26, No. 1 & 2, 2015
farms be expected to behave and perform, and which requirements should be imposed
in order to expect wind farms to support the system? Is it realistic to expect wind
turbines and wind farms to behave as any other power plant? What is the Impact on
thermal loading of lines/transformers? What are the Power Quality Aspects should be
mitigated? What is the behaviour during grid faults/Fault ride through? Reactive
power compensation and voltage control…..etc. Grid codes are set up to specify the
relevant requirements which have to be met in order to integrate wind turbines into the
grid.
This paper will focus on The Egyptian approach to integrate wind power to the
Egyptian Power System and the important issues related to system operation, stability,
protection and the associated technical issues. Grid code requirements for large scale
integration of wind power will also be illustrated.
Keywords: Wind Power, Grid Code, Fault ride-through, Power quality, Wind
forecast
1. INTRODUCTION
Egypt has some of the best and most predictable wind resources in the world along the
Gulf of Suez with mean wind speeds and power densities of 7-10.5 m/s and 350900W/m2 respectively, estimated for a height of 50 m over roughness Class 1. Wind
power development in Egypt has many points in its favour: Egypt’s wind resource is
one of the best in the world; there is ample land available with low alternative
economic value; demand for electricity and other sources of energy is increasing
significantly; air quality considerations in the major cities are one of the key
environmental concerns; donor support has been extremely strong, including studies,
capacity building and grants.
There is already about 550MW of wind generation capacity in service along the
Gulf of Suez with another 3000MW expected to be installed. In addition plans are
underway to develop about further 4200MW along the Nile River to be installed by
2020. Also, an approach to reach a smart grid around the Mediterranean with
exporting renewable energy from southern part to northern part of the sea is envisaged
to be achieved. In order to effectively meet these goals, Egypt is not only committed
to refine and strengthen the legal and regulatory framework governing wind power in
Egypt, but also to provide the necessary reliable background information on the
geographical variation and magnitude of the Egyptian wind resources. A milestone in
this development is the Wind Atlas for Egypt which was published recently by the
New and Renewable Energy Authority (NREA) and the Egyptian Meteorological
Authority (EMA) in Cairo, in cooperation with Risø National Laboratory. However
because of the intermittent nature of wind generated power, its integration with other
generation and demand-side facilities will need to be closely monitored and controlled
by the Egyptian Electricity Transmission Company (EETC) .
As the penetration of wind power continues to grow, there is an increasing need to
develop a consistent and harmonised set of grid connection rules. Connection
requirements are usually issued by system operators in the form of a ‘Grid Code’.
Codes differ, often significantly, from country to country. Due to the rapid growth of
Wind Power Integration To The Transmission Grid: The Egyptian Perspective
145
wind generation, these have historically been developed on an ad hoc basis in response
to immediate technical and regulatory issues. This paper will focus on The Egyptian
approach to integrate wind power to the Egyptian Power System and the important
issues being summarized in the Grid Code.
2. STRATEGY, POLITICAL & GOVERNMENTAL APPROACH AND
INCENTIVES TO SUPPORT RE.
In February 2008, the Supreme Council of Energy set up a target of 20% of the
electrical energy mix coming from renewable sources by the year 2020, mainly from
wind energy (12% reaching more than 7200 MW grid-connected wind farms) and
other renewable (8%) including hydro, solar and biomass).
Efforts are being exerted in order to reach total capacities of 7200 MW and this will
be achieved through two main paths:
1. State-owned projects implemented by the NREA with total capacities of 2375
MW (represents 33% of total installed capacities). These projects will be
financed through governmental agreements.
2. Private sector projects with total capacities of 4825 MW (represents 66% of total
installed capacities).
Policy of increasing the participation of private sector will include two phases:
A. Phase I:
Adopting Competitive Bids approach as the Egyptian Electricity Transmission
Company will issue tenders internationally requesting private sector to supply power
to build, own, operate wind farms and selling electricity for the company with price
agreed upon between the company and the investor
B. Phase II:
Applied of Feed-in-tariff system, taking into consideration the prices and
experience achieved in phase I.
In 26/7/2009, the Supreme Council of Energy has approved the following policies
in order to stimulate and support generating electricity from wind energy:
- Approving private sector participation through competitive tender an bilateral
agreements.
- Reducing project risks through signing long term Power Purchase Agreement,
PPA, for 20- 25 years.
- The Government of Egypt will guarantee all financial obligations under the
(PPA).
- The selling price for energy generated from renewable energy projects will be in
foreign currency in addition to a portion, covers operation and maintenance
costs, in local currency.
- Investors will benefit from selling certificates of emission reduction resulted
from the project implemented.
- Evaluation criteria for tenders of renewable energy projects will give privilege
for local components.
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Energy & Environment · Vol. 26, No. 1 & 2, 2015
- Forming mutual committee of representatives from Ministers of Petroleum,
Electricity, Finance and Investment in order to prepare proposals for land use
agreement to implement wind projects. In 26/5/2010 the cabinet has approved
the committee proposals for encouraging private sector participation through:
• Exempting renewable energy equipment from custom duties.
• Obtaining all the required permits to allocate the lands and clearing it from
land mines.
• Preparing the required studies for implementing projects such as
environmental impact assessment including bird migration and soil research
studies, etc.
- The land shall be allocated according to the following conditions:
• Recapturing the land after ending the life time of the project NREA will
restore the actual costs of preparing the land for the projects and these costs
will be part of the project investment costs.
• The investors shall pay these costs on annual installments from 3 – 5 years,
after the beginning of the project operation.
• In 16 /5 /2011 the Supreme Council of Energy has approved the incentives
applied for RE projects. In addition paragraph (A- 1) in the formed committee
has been modified to ((the investors will be given the land to implement RE
projects through usufruct agreement against payment equivalent to a
percentage of the annual produced energy and will be determined by the
cabinet. The land will be recaptured after dismantling the projects components
at the end of the project life time.
3. REQUIREMENTS FOR WIND OWER PLANTS IN TRANSMISSION
NETWORKS
Increasing wind power penetration levels to the power systems of many regions
and countries has led to the elaboration of specific technical requirements for the
connection of large wind farms, usually as a part of the grid codes issued by the
Transmission System Operators (TSOs). These requirements typically refer to large
wind farms, connected to the transmission system, rather than smaller stations
connected to the distribution network. Currently, the existing technology in wind
farm’s generators are either Squirrel Cage IG, Variable Resistance IG, or Double-fed
Induction Generator (DFIG). These technology are equipped with traditional
protection (under/over voltage, under/over frequency) with specific time delay setting.
The new grid codes stipulate that wind farms should contribute to power system
control (frequency and also voltage), much as the conventional power stations, and
focus on wind farm behaviour in case of abnormal operating conditions of the network
( such as in case of Riding the voltage dips due to network faults).
Figure 1 illustrates typical MWs output from Zafarana wind farm within two days
in two months. The GWh during one year 2010/2011 of the wind farm is also
illustrated in Figure 2. These changes in the output power raise challenges for the
integration of large amounts of concentrated wind power into the electricity grids. In
order to integrate wind power successfully, a number of issues need to be addressed
by the utility taking into account such considerable share of wind power.
Wind Power Integration To The Transmission Grid: The Egyptian Perspective
147
These requirements guarantee a stable, profitable and highly qualitative supply of
wind energy [1, 2]:
1. Wind turbines have to be able to remain in operation without reducing
performance and without time limits even with considerable voltage and
frequency fluctuations.
2. If voltage dips occur due to grid problems, wind turbines have to remain
connected to the grid for a defined period of time.
3. Short-circuit current power feed-in may be requested during a grid fault.
Depending on the grid, the turbine has to be able to feed in primarily active or
reactive power to the grid.
4. Abrupt grid frequency changes should not cause the wind turbine to shut down.
5. During a failure and while a grid fault is being cleared, reactive power
absorption by wind generators is restricted or not permissible at all.
6. After a fault has been remedied, a wind farm should resume power feed as
quickly as possible within a specified maximum time range.
7. Wind farms should be able to operate with reduced power output with no time
restrictions.
8. For coordinated load distribution in the ride, the increase in power output
(power gradient), for example when the wind farm is starting, should be able to
be restricted in accordance with the grid operator’s specifications.
9. Wind farms have to be able to contribute reserve energy within the grid.
If grid frequency increases, the power output of a wind farm should be reduced.
10. If necessary, wind farms should be able to contribute to maintaining voltage
stability in the grid by supplying or absorbing reactive power with no time
restrictions. Dynamic criteria to maintain grid stability must be met.
11. Wind farms must be able to be integrated into the grid control system for
remote monitoring and control of all components in the grid.
Figure 1: Typical output in MWs from Zafarana wind farm within two days
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Energy & Environment · Vol. 26, No. 1 & 2, 2015
Figure 2: GWh output from Zafarana during year 2010/2011
To assure these requirements, utilities specify Grid Code that includes mandatory
obligations to be fulfilled. These obligations differ from utility to another according to
the grid and the location of wind resources.
In the following section these obligations are emphasized as summarized in the
Egyptian Grid Code for wind integration.
4. CHALLENGES DUE TO THE CONNECTION OF LARGE WIND FARMS
TO THE TRANSMISSION NETWORK.
In order to accommodate and safely operate a high level of variable wind power
generation on power system, many challenges on both wind power transmission
technologies and transmission grid operation arise. These include [1: 14]:
• Fault ride through requirements;
• System frequency and frequency response requirements;
• Transmission system voltage and reactive power capability requirements;
• wind power forecasts requirements. Remote operation requirements;
• Power Quality and Protection Requirements
In the following subsections, these challenges will be illustrated. World-wide and
local experiences as well as lessons learned have been taken into consideration
during preparation of this Code. The Egyptian Wind Farm Grid Connection Code will
be applied to Wind Farms that are connected to the Transmission Grid. Also,
replacement of and radical changes in existing wind turbine generators is also
considered as new units.
Wind Power Integration To The Transmission Grid: The Egyptian Perspective
149
4.1 Fault (low voltage) ride through (FRT) requirements.
The large increase in the installed wind capacity in transmission systems necessitates
that wind generation remains in operation in the event of network disturbances. For
this reason, grid codes issued during the last years invariably demand that wind farms
(especially those connected to HV grids) must withstand voltage dips to a certain
percentage of the nominal voltage (down to 0% in some cases) and for a specified
duration. Such requirements are known as Fault Ride Through (FRT) or Low Voltage
Ride Through (LVRT) and they are described by a voltage vs. time characteristic,
denoting the minimum required immunity of the wind power station.
The FRT requirements also include fast active and reactive power restoration to the
prefault values, after the system voltage returns to normal operation levels. Some
codes impose increased reactive power generation by the wind turbines during the
disturbance, in order to provide voltage support, a requirement that resembles the
behaviour of conventional synchronous generators in over-excited operation.
Figure 3 presents FRT requirements which stipulate that wind farms must remain
connected during voltage dips down to 0% and recovering to 90% should be achieved
at max of 3 seconds. However, it must be noted that these requirements apply to the
connection point (point of common coupling) of the network, generally at HV level.
Figure 3: Fault ride through profile for a Wind Farm
After fault clearance the active power output of the Wind Farm must reach the same
level as before the fault within a time period of 10 s after fault clearance. After fault
clearance the consumption of reactive power of the Wind Farm must be equal or below
the consumption of reactive power before the fault.
For non-successful auto-reclosures two successive temporary voltage drops can
occur, as shown in Figure 4. The wind turbine generators have to ride-through both
temporary voltage drops temporary voltage drops due to a non-successful autoreclosure
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Energy & Environment · Vol. 26, No. 1 & 2, 2015
reconnection
to fault
Auto reclosure
0.8 - 5 sec.
Fault entrance
Voltage at connection point
100
U / Un / %
80
60
40
20
time / ms
0
0 150
0
150
Figure 4: Temporary voltage drops due to a non-successful auto-reclosure
4.2 Active Power Control, Voltage and frequency operating range
Wind farms must be capable of operating continuously within the voltage and
frequency variation limits encountered in normal operation of the system. Further,
they should remain in operation in case of voltage and frequency excursions outside
the normal operation limits, for a limited time and in some cases at reduced output
power capability. The Wind Farm is not allowed to reduce output power within the
frequency range of 47.5 Hz up to 50.2 Hz due to variations in the grid frequency or in
the grid voltage at the Grid Connection Point for the time periods given in Figure 5.
Voltage [kV]
575 253
t 30 min
t 20 min
t 10 min
220
500
550 242
t 30 min
continuously
450 198
425 187
47
48
49
50
51
52
Frequency [Hz]
Figure 5: Requirements on the output power of the Wind Farm in case of grid
frequency and grid voltage variations (quasi-stationary observation)
Wind Power Integration To The Transmission Grid: The Egyptian Perspective
151
For grid frequencies in the range from 50.2 Hz to 51.5 Hz the wind turbine generators
of the Wind Farm have to reduce active output power with a rate of 40% of actual
active output power per Hertz as illustrated in Figure 6.
120
PM
100
r
e 80
w
o
p
e 60
v
it
c
a 40
20
0
50
50.5
51
51.5
frequency [Hz]
Figure 6: Active power reduction due to over-frequency
In addition to these requirements, the Wind Farm must have an input signal for a setpoint value at the Grid Connection Point, to reduce the active output power. The Grid
Operator will provide the set-point signal. In case of an active output power reduction,
the Wind Farm must follow the set-point signal of the Grid Operator within one
minute.
4.3 Reactive Power Range / Voltage Control
Conventional synchronous generators are required to control the AC voltage and
exchange reactive power, in accordance with the needs of the AC system, and
according to settings determined by the transmission system operators. They achieve
this by varying generator excitation and on load tap changers. It is necessary for the
security of grid operation that wind generation can also provide this capability,
especially if its penetration in the system is large.
A common requirement is that the wind farm shall be able to operate with a power
factor anywhere between defined leading and lagging power factors at the grid
connection point. There may also be incentives or penalties for specific power factor
requirements either by bilateral agreement, or by grid code. Figure 7 shows
requirements for power factor variation range in relation to the voltage, according to
the Code. Even at reduced active power output, reactive power supply at the highvoltage terminals at the Grid Connection Point shall fully correspond to the P-QDiagram
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Energy & Environment · Vol. 26, No. 1 & 2, 2015
Power Factor
0,95 leading
Reactive power Q
max. Q cap.
leading
0
max. Q ind.
lagging
Power Factor
0,95 lagging
0,00
20,00
40,00
60,00
80,00
100,00
active power in % of rated
Figure 7: Reactive power in relation to active power according to the
4.4. Wind power forecasts requirements.
A forecast of wind generation is an additional input to the pre-dispatch demand
forecasting processes. Grid Codes specify that controllable wind farms should provide
their wind power output forecasts at least once a day for the following 48 hours for, as
an example, each 30- minute interval. A forecast update must also be available in
National Control Center (NCC). The accuracy of the wind power forecasts depends
of a number of factors, the most important being the wind speed forecast.
Figure 8 shows an example of forecast error in data for a wind farm in New Zealand
from April 2006 through to February 2009. It looks at the wind generation forecast,
available at 4am, for the 7am to 7pm period, and illustrates the probability of the
overall forecast error expressed in MWhs.
Figure 8: Example of forecast errors in energy terms (MWh) for forecasts made by
4am for 7am-7pm
Wind Power Integration To The Transmission Grid: The Egyptian Perspective
153
4.5 Real Time Data - Remote operation requirements.
The Wind Farm must have technical equipment at the Grid Connection Point to
transfer the important information for the power system management systems
furnished with a real-time. These requirements include the feasibility to exchange
signals between WPS and TSO [1, 2]. Among the signals that WPS should make
available to the TSO’s remote terminal units (RTU) are:
Grid connected transformer (GCT) tap positions;
• Voltage at the GCT low voltage terminals;
• Active and reactive power output at the LV side of the GCT;
• Voltage regulation system set-point (in kV);
• On/Off status indications for reactive power devices;
• MV Circuit-breaker position indications.
For WPS with an installed capacity in excess of 10 MW the following signals are also
required:
• Meteorological data (wind speed and direction at hub height, air temperature and
pressure);
• Wind power station availability (0-100 % signal);
Among the control signals from the TSO to wind power stations are:
• A MW control facility status signal
• A MW curtailment set-point signal defining the maximum active power output
permitted from the WPS;
• Voltage set-point for voltage regulation purposes;
4.6 Power Quality and Protection Requirements
Also Protection system requirements shall guarantee safe and reliable operation to
both the power system as well as the wind farm. The grid protection of the Wind Farm
shall be performed according to the Protection Code of the Grid Code. The settings of
the grid protection device in the wind turbine generators of the Wind Farm must
conform to Table 1, unless agreed otherwise with the Grid Operator in the Connection
Agreement.
Table 1: Setting of the grid protection at the wind turbine generators
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Energy & Environment · Vol. 26, No. 1 & 2, 2015
All the Wind Farms connected to the Grid shall endeavour to maintain the voltage
wave-form quality at the Grid Connection Point. The Wind Farms shall comply with
the requirements of Power Quality Standards and Protection requirements of the Grid
Code unless other requirements stated in the connection agreement. These
requirements, as found in the code [2], include Harmonic levels, Total harmonic
distortion, Flicker, Voltage unbalance, Voltage fluctuations and Voltage change.
For monitoring and recording purposes, a phasor measurement unit [14:18]
supports the IEEE C37.118-2005 standard with GPS source with minimum accuracy
1 µsec should be installed at the Grid Connection Point for real-time monitoring and
measuring for voltage, current magnitude and phase, frequency, active and reactive
power….etc. Power Quality measurement and recording at the Connection Point shall
be performed according to the Metering code of the Grid Code.
5. CONCLUSION
• The complexity of the interconnection of wind farms to the power grid stems
from the fact that wind energy is variable in nature and sometimes difficult to
predict. To keep the grid operation stable, there is a need to ensure that other
power generation sources are available to compensate for the variability of the
aggregated wind generation.
• The associated technical issues are mainly related to the flexibility of the power
system in adjusting its generation to the aggregated wind production.
• Wind farms are located somewhat remote from the Egyptian power grid.
Therefore, the utility has to ensure the sufficiency of power transmission
capacity. A rather unique feature of wind power in Egypt is that most of the wind
resources are concentrated in the Gulf of Suez and Gulf El-Zayt areas. This
raises the additional issues of the impact on the system when large amount of
wind power is connected at certain points of the network.
• The requirements in the new Wind Integration Grid Code requirements are
summarized in this paper. The expected fast growing penetration of the WP
within the existing Egyptian Power System has to be faced also by adding new
equipments and technologies to closely monitor and adapt RE integrated to the
grid.
REFERENCES
[1]
Mohamed El-Hadidy, Dalal Helmi, Fatma Nada, Soufie Basta,” How Wind Farms Affect
the Grid Performance” Cigre Regional Meeting, Qatar 2010 (Best Applied Research
Award).
[2]
“Wind Farm Grid Connection Code” as part of the Egyptian Transmission Grid Code, 1st
Draft on 5th January 2012. [3]
www.aeso.ca
[4]
www.hydroquebec.com/transenergie/en
[5]
www.ieso.ca
[6]
www.nationalgrid.com
[7]
www.ferc.gov
Wind Power Integration To The Transmission Grid: The Egyptian Perspective
155
[8]
www.nerc.com
[9]
Cigre Report WG B4.39, “Integration of Large Scale Wind Generation Using HVDC and
Power Electronics”, Feb, 2009.
[10] Ivan Dudurych, Hugh Jones, Michael Power, ” The Control of a Power System with a
High Wind Power Penetration: Ireland’s Experience”, CIGRE 2008.
[11] C. Alvarez, H. Amarís. O. Samuelsson , “Voltage dip mitigation at Wind Farms”
www.ing.uc3m.es.
[12] Ch. Eping, J. Stenzel, M. PÄoller, H. MÄuller, ” Impact of Large Scale Wind Power on
Power System Stability”, www.eev.tu-darmstadt.de.
[13] P. Pourbeik, R. J. Koessler, D. L. Dickmander and W. Wong, “integration of Large Wind
Farms into Utility Grids (Part 2 - Performance Issues)”, www.us.abb.com.
[14] Consultation Paper by Electricity Commission “Wind forecasting and market integration:
options”, 17 March 2010.
[15] Mohamed El-Hadidy, Dalal Helmi, “The Need for Modern Strategy to Control the
Interconnected Power Systems in the Arab Region” GCC Power 2008 Conference &
Exhibition Manama 9th – 12th November 2008.
[16] Mohamed El-Hadidy, Dalal Helmi “Starting Synchrophasor Measurements in Egypt: A
Pilot Project Using Fault Recorders”, 12th MEPCON’2008, IEEE ISBN: 978-1-42441933-3, Aswan, Egypt,
[17] Mohamed El-Hadidy, Dalal Helmi “Synchrophasors: The True Picture of the Power
System Dynamics”, Arab CIGRE, Jordan 2007.
[18] John Dumas, “Maintaining Reliability with Increased Wind Penetration”, ERCOT, 10-072009
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