Renewable Energy Integration: Power Quality Issue IV - Power Quality issues... · •Without...
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Renewable Energy Integration:Power Quality IssuePower Quality IssuePower Quality IssuePower Quality IssuePower Quality IssuePower Quality IssuePower Quality IssuePower Quality Issue
Energy Integration:Power Quality IssuePower Quality IssuePower Quality IssuePower Quality IssuePower Quality IssuePower Quality IssuePower Quality IssuePower Quality Issue
Vikram Singh
Director( Grid Management)
Central Electricity Authority
Power quality
• Term ‘Power quality’ not defined in EA 2003, CEA regulations or IEGC.
• Power quality is a measure of the fitness of electrical power devices.
• “The characteristics of the electricity at a given point on an electrical system, • “The characteristics of the electricity at a given point on an electrical system, evaluated against a set of reference technical parameters
• Without quality power, electrical device (or load) may malfunction, fail prematurely. Poor quality device may pollute Grid power.
• PQ is a critical concern, inefficiency, & damages to production quality.
• success of ‘Make in India” needs high PQ standards
Power quality
’ not defined in EA 2003, CEA regulations or IEGC.
fitness of electrical power fed into the consumer
The characteristics of the electricity at a given point on an electrical system, The characteristics of the electricity at a given point on an electrical system, evaluated against a set of reference technical parameters”.
electrical device (or load) may malfunction, fail prematurely. Poor quality device may pollute Grid power.
damages to equipment, high losses, poor
needs high PQ standards
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Power quality parameters
1. Supply : Interruptions
2. Magnitude: Sag, Swell, under and over deviation, transients
3. Frequency: Over and under frequency
4. Waveform: Harmonics, and sub harmonics4. Waveform: Harmonics, and sub harmonics
5. Phase: Unbalance
parameters
Sag, Swell, under and over deviation, transients
: Over and under frequency
: Harmonics, and sub harmonics
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: Harmonics, and sub harmonics
Power quality Parameters considered in CEA technical Standards
Regulation 3 (a) of CEA (Grid Standards) Regulations 2010
Frequency:
close to 50 Hz and shall not allow it to go beyond the range
narrower frequency band specified in the Grid Code, except during the transient
period following tripping.
(Grid Code specifies range: 49.90 to 50.05 Hz)
Parameters considered in CEA technical Standards
Regulation 3 (a) of CEA (Grid Standards) Regulations 2010
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to 50 Hz and shall not allow it to go beyond the range 49.2 to 50.3 Hz or a
narrower frequency band specified in the Grid Code, except during the transient
(Grid Code specifies range: 49.90 to 50.05 Hz)
Frequency ProfileFrequency ProfileFrequency ProfileFrequency ProfileSource: POSOCO
Frequency ProfileFrequency ProfileFrequency ProfileFrequency ProfileSource: POSOCO
Frequency ProfileFrequency ProfileFrequency ProfileFrequency ProfileSource: POSOCO
Grid Standards
S. No. Nominal System Voltage (kV
rms)
Maximum (kV
1 765
3 (1) (b) maintain the steady state voltage within the limits specified below
1 765
2 400
3 220
4 132
5 110
6 66
7 33
Grid Standards
Maximum (kV
rms)
Minimum (kV
rms)
800 728
within the limits specified below
800 728
420 380
245 198
145 122
121 99
72 60
36 30
Voltage over voltage and unbalance
S. No. Nominal System Voltage (kV rms
3 (1) ( c) ensure that the temporary over voltage
remains within the limits specified
1 765
2 400
3 220
4 132
Below 132 kV, respective SERC to decide in the respective Grid Code
Voltage over voltage and unbalance
rms) Phase to Neutral (kV peak)
temporary over voltage due to sudden load rejection
914
514
283
170
decide in the respective Grid Code
Voltage unbalance
S. No. Nominal System Voltage (kV
3 (1) (d) ensure that the maximum permissible values of voltage unbalance
shall be as specified in Table below:-
S. No. Nominal System Voltage (kV
rms)
1 765 and 400
2 220
3 132 to 33
Provided that Bulk consumers shall avoid unbalanced load during operation:
Provided further that the distribution licensees shall ensure that their loads are not
Nominal System Voltage (kV Voltage unbalance
) ensure that the maximum permissible values of voltage unbalance
Nominal System Voltage (kV Voltage unbalance
(%)
1.5
2
3
Provided that Bulk consumers shall avoid unbalanced load during operation:
shall ensure that their loads are not unbalanced.
Load crash of NR on 11Load crash of NR on 11Load crash of NR on 11Load crash of NR on 11
�Load crash of around 6500 MW due to rain and thunderstorm on
12.12.2017
� Punjab, Haryana, Uttar Pradesh, J&K,
�High frequency and high voltage condition prevailed.
Frequency touched 50.18Hz at 06:01hrs/12.12.2017.�Frequency touched 50.18Hz at 06:01hrs/12.12.2017.
�22 no. of 400kV lines and ICTs tripped during the period.
�54 no. of 400kV and 5 ICTs opened manually.
Load crash of NR on 11Load crash of NR on 11Load crash of NR on 11Load crash of NR on 11---- 12.12.201712.12.201712.12.201712.12.2017
Load crash of around 6500 MW due to rain and thunderstorm on
Punjab, Haryana, Uttar Pradesh, J&K, Himachal Pradesh & Uttarakhand.
frequency and high voltage condition prevailed.
at 06:01hrs/12.12.2017.at 06:01hrs/12.12.2017.
tripped during the period.
opened manually.
Source: POSOCO
Source: POSOCO
Tripping due to over voltage
On 12.12.2017 around
Tripping due to over voltage
Grid Standards: Voltage Harmonics
S.No.System Voltage (kV
rms)
Total Harmonic
Distortion (%)
3 (2) The transmission licensee shall ensure that the
maintained at all points in the Grid by observing the limits given in Table
S.No.rms) Distortion (%)
1 765 1.5
2 400 2
3 220 2.5
4 33 to 132 5
Grid Standards: Voltage Harmonics
Total Harmonic
Distortion (%)
Individual Harmonic of any
particular Frequency
) The transmission licensee shall ensure that the voltage wave-form quality is
maintained at all points in the Grid by observing the limits given in Table below,-
Distortion (%)particular Frequency
(%)
1
1.5
2
3
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CEA(Technical CEA(Technical CEA(Technical CEA(Technical Standard for Grid Connectivity) Standard for Grid Connectivity) Standard for Grid Connectivity) Standard for Grid Connectivity) Regulations, 2007Regulations, 2007Regulations, 2007Regulations, 2007
Part-IV : Grid Connectivity Standards applicable to the Distribution Systems and Bulk Consumers
3. Voltage and Current Harmonics3. Voltage and Current Harmonics
1) The total harmonic distortion for voltage at the connection point shall not exceed 5% with no individual harmonic higher than 3%.
2) The total harmonic distortion for current drawn from the transmission system at the connection point shall not exceed 8%.
Standard for Grid Connectivity) Standard for Grid Connectivity) Standard for Grid Connectivity) Standard for Grid Connectivity)
Connectivity Standards applicable to the Distribution Systems and Bulk
The total harmonic distortion for voltage at the connection point shall not exceed 5% with no individual harmonic higher than 3%.
The total harmonic distortion for current drawn from the transmission system at the
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4. Voltage Unbalance
The Voltage Unbalance at 33kV and above shall not exceed 3.0%.
5. Voltage Fluctuations
CEA(Technical Standard for Grid CEA(Technical Standard for Grid CEA(Technical Standard for Grid CEA(Technical Standard for Grid Connectivity) Regulations, 2007Connectivity) Regulations, 2007Connectivity) Regulations, 2007Connectivity) Regulations, 2007
5. Voltage Fluctuations
1) The permissible limit for step changes which may occur repetitively
is 1.5%.
2) For occasional fluctuations other than step changes the maximum
permissible limit is 3%.
The Voltage Unbalance at 33kV and above shall not exceed 3.0%.
CEA(Technical Standard for Grid CEA(Technical Standard for Grid CEA(Technical Standard for Grid CEA(Technical Standard for Grid Connectivity) Regulations, 2007Connectivity) Regulations, 2007Connectivity) Regulations, 2007Connectivity) Regulations, 2007
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The permissible limit for step changes which may occur repetitively
For occasional fluctuations other than step changes the maximum
CEA(Technical Standard for Grid Connectivity) Regulations, 2007: Part-II :
5) The project of the requester shall not cause voltage and current harmonics limits specified in IEEE Standard 519
B. For wind and generating station using inverter B. For wind and generating station using inverter
B1. Requirement with respect to Harmonics, DC
1.Current harmonic as per IEEE 519.
2.DC current not greater than 0.5% of full rated output at inter connection point.
3.Flicker limit as per IEC 61000
Standard for Grid Connectivity)
5) The project of the requester shall not cause voltage and current harmonics which exceed
B. For wind and generating station using inverter B. For wind and generating station using inverter
DC Injection and Flicker
DC current not greater than 0.5% of full rated output at inter connection point.
Continued
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CEA(Technical Standard for Grid Connectivity) Regulations, 2007: Part-II :
Measurement of harmonic content, DC injection and flicker shall Measurement of harmonic content, DC injection and flicker shall a year in the presence of parties concern.
Provided in addition to above if a licensee desire to measure harmonic content, or DC injection or flicker, it shall inform the other party in writing and measurement shall be carried out with in 5 working days.
Standard for Grid Connectivity)
harmonic content, DC injection and flicker shall be done at least once in harmonic content, DC injection and flicker shall be done at least once in
Provided in addition to above if a licensee desire to measure harmonic content, or DC injection or flicker, it shall inform the other party in writing and measurement shall be
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CEA(Technical Standard for Connectivity of the CEA(Technical Standard for Connectivity of the CEA(Technical Standard for Connectivity of the CEA(Technical Standard for Connectivity of the distributed generation resources) Regulations, 2013distributed generation resources) Regulations, 2013distributed generation resources) Regulations, 2013distributed generation resources) Regulations, 2013
11. Standards for distributed generation resources
1. Harmonic Current injection from a generating station shall not exceed the limit specified in IEEE standard 519. IEEE standard 519.
2. The distributed generating resource shall not inject DC current greater than 0.5% of full rated output at interconnection point.
3. The distributed generating resource shall not introduce flicker beyond limits specified in IEC 61000.
Provided that the standards for flicker will come into effect from 1st April 2014.
CEA(Technical Standard for Connectivity of the CEA(Technical Standard for Connectivity of the CEA(Technical Standard for Connectivity of the CEA(Technical Standard for Connectivity of the distributed generation resources) Regulations, 2013distributed generation resources) Regulations, 2013distributed generation resources) Regulations, 2013distributed generation resources) Regulations, 2013
11. Standards for distributed generation resources
Harmonic Current injection from a generating station shall not exceed the limit specified in
The distributed generating resource shall not inject DC current greater than 0.5% of full
The distributed generating resource shall not introduce flicker beyond limits specified in
that the standards for flicker will come into effect from 1st April 2014.
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Network Operator (discom/transcom
: Voltage & Impedance
Customer : current
( however above relationship not straight)
Who is responsible for Power
( however above relationship not straight)
Manufacturer/Industry : Emission &
transcom)
Voltage & Impedance
Customer : current
( however above relationship not straight)
Who is responsible for Power Quality
( however above relationship not straight)
Emission & Immunity
Power Quality Parameters observed 175 s/stn, 500
Quality Parameters observed ( Swachh Power report 2015), 500 feeders
Source: POWERGRID
Source: PGCIL’s Swachh Power Report (
2015)
Transmission system voltages and current rich in 5th &
7th harmonics.
LT level have high content of 3rd harmonics.
Critical
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Critical
NR &NER: Sag and Voltage Imbalance,
WR&SR :Harmonics and Sag
ER: Harmonics
Industry Concerns• Apart from harmonics, Industry is also affected due to factors like
interruptions, Flickers Voltage Dips Voltage swell and Unbalance.
• As per Asia Power Quality Initiative Survey Report In September 2015 :
Apart from harmonics, Industry is also affected due to factors like interruptions, Flickers Voltage Dips Voltage swell and Unbalance.
As per Asia Power Quality Initiative Survey Report In September 2015 :
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Issues and their impactIssues and their impact
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Source of harmonics• Switched mode power supplies
• Dimmers
• Current Regulators
• Frequency Converters
• Voltage source inverters with pulse width modulated converters
• Low power consumption, LEDs lamps
• Electrical arc-furnaces
• Arc welding machines
• Induction motors with irregular magnetizing current associated with saturation of the iron
• All equipment with built-in switching devices or with internal loads with noncharacteristics
• Charging Stations for EVs
Voltage source inverters with pulse width modulated converters
motors with irregular magnetizing current associated with saturation of the iron
in switching devices or with internal loads with non-linear voltage/current
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Sub synchronous Resonance and low frequency: HVDC converter Sub synchronous Resonance and low frequency: HVDC converter Sub synchronous Resonance and low frequency: HVDC converter Sub synchronous Resonance and low frequency: HVDC converter
SSR frequency filtered from voltage oscillation indicating presence of two
Bus frequency measured from fault recorder indicating 6.69 HZ oscillation.
SSR frequency filtered from voltage oscillation representing
Sub synchronous Resonance and low frequency: HVDC converter Sub synchronous Resonance and low frequency: HVDC converter Sub synchronous Resonance and low frequency: HVDC converter Sub synchronous Resonance and low frequency: HVDC converter
SSR frequency filtered from voltage oscillation indicating presence of two frequencies superimposed on each other.
Bus frequency measured from fault recorder indicating 6.69 HZ oscillation.
SSR frequency filtered from voltage oscillation representing 15.55 Hz and 11.15 Hz respectively.
Inter area oscillations : 0.2 Hz mode
Undamped oscillation observed in the AC tie line on 28th January 2014.
Impact: black out: 1996, 2003- US_canada, 2011 Chile
Inter area oscillations : 0.2 Hz modeSource: POSOCO
Undamped oscillation observed in the AC tie line on 28th January 2014.
Shortcomings in existing standards
• Lack of clarity on measurement of harmonics w.r.t. Issue of Point of Common Coupling
• Lack of clarity on quantum of injection of harmonics by
• Computation of Total demand Distortion(TDD), on demand current or agreed power.
• No monitoring and implementation framework for voltage variation and harmonics• No monitoring and implementation framework for voltage variation and harmonics
• Responsibility of Consumer w.r.t harmonics injection &corrective actions required.
• No provisions for penalty or incentive in the regulations.
• Regulations are silent on other issues of sub–harmonics, inter harmonics, etc. perspective is needed.
• Applicable to only discoms and bulk consumers drawing power at 33 kV& above
Shortcomings in existing standards
Lack of clarity on measurement of harmonics w.r.t. Issue of Point of Common Coupling
Lack of clarity on quantum of injection of harmonics by indiv. consumers
Computation of Total demand Distortion(TDD), on demand current or agreed power.
No monitoring and implementation framework for voltage variation and harmonicsNo monitoring and implementation framework for voltage variation and harmonics
Responsibility of Consumer w.r.t harmonics injection &corrective actions required.
No provisions for penalty or incentive in the regulations.
harmonics, inter harmonics, etc. - so broader
and bulk consumers drawing power at 33 kV& above
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Proposed changes in connectivity standards
Voltage and Current Harmonics
• Limits of injection of current harmonics by bulk consumers of Common Coupling (PCC), method of harmonic measurement and other matters, IEEE 519-2014 IEEE 519-2014
• Provided that Distribution licensee, to ensure compliance at grid connection points, may make provision in respective supply code made by respective SERC to limit harmonic injection by consumers in its own system.
• For multiple consumers , the allocation of harmonic limits shall be in accordance with the maximum demand recorded during last one year at a PCC..
• The measurement of harmonics shall be done at PCC and not at consumer premises
• At PCC, metering of harmonics will be done to ensure that Voltage harmonics are within prescribed limits on utility side and current harmonics are within prescribed limits for each user.
changes in connectivity standards
consumers and point of harmonic measurement i.e Point of Common Coupling (PCC), method of harmonic measurement and other matters, in accordance with the
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to ensure compliance at grid connection points, may make provision in respective supply code made by respective SERC to limit harmonic injection by consumers in its own
allocation of harmonic limits shall be in accordance with the maximum
of harmonics shall be done at PCC and not at consumer premises.
At PCC, metering of harmonics will be done to ensure that Voltage harmonics are within prescribed limits on utility side and current harmonics are within prescribed limits for each user.
Harmonics (Proposed)
Voltage and Current Harmonics (contd..)
• Utility shall install Power Quality meters in a phased manner within next three years of publication of this regulation covering at least 33% of the identified measuring points each year
• PCC position shall be decided by utility based on network configuration • PCC position shall be decided by utility based on network configuration mixed user (LV side).
• Measuring and metering of harmonics shall be a continuous process with permanent metersto IEC 61000-4-30 Class A and capable of detecting direction of Harmonics
downstream) and data in regard to harmonics should be available with utility and it is to be shared with consumer. This is to ensure continuous compliance as distortion limits are to be calculated based on daily and weekly percentile values.
meters in a phased manner within next three years of publication of this regulation covering at least 33% of the identified measuring points each year.
PCC position shall be decided by utility based on network configuration i.e dedicated user (HV side) or
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PCC position shall be decided by utility based on network configuration i.e dedicated user (HV side) or
Measuring and metering of harmonics shall be a continuous process with permanent meters complying capable of detecting direction of Harmonics (whether it is upstream or
regard to harmonics should be available with utility and it is to be shared This is to ensure continuous compliance as distortion limits are to be calculated based
Harmonics (Proposed)
Voltage and Current Harmonics ( contd..)
� In addition to harmonics, periodic measurement of other power quality parameters like
voltage sag, swell and disruptions shall be done on monthly
shared with consumers.shared with consumers.
� In addition to the meters for monitoring of quality
with regard to continuous measurement of quality
consumers having load more than threshold
These consumers shall install meters at their
required by utility.
In addition to harmonics, periodic measurement of other power quality parameters like
voltage sag, swell and disruptions shall be done on monthly basis and reports shall be
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quality to be installed by utility, the provision
quality parameters shall also be applicable for
limit as decided by appropriate Commission.
their own expenses and share data as and when
Issues before Authority
• Applicable to only discoms and bulk consumers drawing power at 33 kV and above
• Railways has sought relaxation on current harmonics while its voltage harmonics are within CEA prescribed limits.
• IEEE 519 is only a recommendation and
Issues before Authority
and bulk consumers drawing power at 33 kV
sought relaxation on current harmonics while its voltage harmonics are within CEA prescribed limits.
and not a standard.
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Draft distribution network standard ( CEA drafted and sent to ET 45)
• The scope of this standard is to specify main characteristics of voltage at network user’s supply terminal in a distribution system. The characteristic are :• Frequency• Magnitude • Waveform • Symmetry of the line voltages • Waveform • Symmetry of the line voltages ( EN 50160:2010-5 as reference)
• -Definitions includes Low, Medium and High voltages.
• -Values of individual characteristics parameters (flicker severity, voltage dip, swell,
unbalance, Harmonic & inter-harmonin , transient voltages
• -Measurement as per IEC 61000-4-30
• -When notified by BIS, these standards will be adopted
network supply voltage quality
The scope of this standard is to specify main characteristics of voltage at network user’s supply terminal in a distribution system. The characteristic are :
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Definitions includes Low, Medium and High voltages.
parameters (flicker severity, voltage dip, swell,
, transient voltages etc provided
these standards will be adopted in CEA regulations.
Way forward: Proper implementation
• As measurement and monitoring of harmonics The proposed amendment of CEA regulations would have necessary provisions. provisions.
• Grid codes to put in place a mechanism to check non compliance power quality.
• Consider separately Power quality indices/ KPI while valuating the standards of performance of DISCOMs (
Way forward: Proper implementation
and monitoring of harmonics had been an ignored area. The proposed amendment of CEA regulations would have necessary
to put in place a mechanism to check non compliance of
separately Power quality indices/ KPI while valuating the standards of performance of DISCOMs (SoP).
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Amendments considering Large scale RE integration
• Large Scale Integration of Renewable with Grid :
• Ambitious target of 175 GW Renewable Capacity by 2022 system operation in regards to Balancing and secure operation of All India Grid.
• During day sufficient conventional capacity may not be available to give adequate reserves.
• Draft national Electricity Plan 2017-22( to be published shortly) indicate that Grid Management during morning and evening RAMP would be a challenge. Management during morning and evening RAMP would be a challenge.
• Renewable generation should not trip under temporary low voltage or high voltage condition due to incident elsewhere in the grid.
• Using Renewable generation as tool for grid security i.e. as asset for system operator rather than liability .
mendments considering Large scale RE integration
Large Scale Integration of Renewable with Grid :
175 GW Renewable Capacity by 2022 will increase challenge of system operation in regards to Balancing and secure operation of All India Grid.
During day sufficient conventional capacity may not be available to give adequate
22( to be published shortly) indicate that Grid Management during morning and evening RAMP would be a challenge. Management during morning and evening RAMP would be a challenge.
Renewable generation should not trip under temporary low voltage or high voltage condition
Using Renewable generation as tool for grid security i.e. as asset for system operator rather
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Existing Regulations
• Part B of the Existing Regulations deal with Connectivity Standards applicable to the Wind Generating stations and generating standards having inverters.
• B1. Requirement with respect to harmonics, Direct Current ( DC ) injection and Flickersinjection and Flickers
• Major amendments are proposed in :
• B. 2 For generating stations getting connected on or after 6 month form date of publication
Harmonics current Limits
DC Injection
Flicker
Part B of the Existing Regulations deal with Connectivity Standards applicable to the Wind Generating stations and generating standards
B1. Requirement with respect to harmonics, Direct Current ( DC )
Major amendments are proposed in :
B. 2 For generating stations getting connected on or after 6 month
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IEEE 519
Less than 0.5% of Full load Current
IEC 61000
Proposed Amendments
1.Primary response by Wind & Solar power stations
2. LVRT and HVRT on Renewable Generators
3.Ramp Up & Ramp Down rates specified for RES.
4. Voltage Regulation services for RES.
7.Reactive Power control capability 7.Reactive Power control capability
8.Review of limits of Harmonics
9.Compliance Monitoring
Proposed Amendments
response by Wind & Solar power stations
LVRT and HVRT on Renewable Generators
specified for RES.
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Frequency Range & Active power control• Existing
• The generating unit shall be capable of operating in the frequency range of 47.5 to 52 Hz and shall be able to deliver rated output in the frequency range of 49.5 Hz to 50.5 Hz.
• Proposed:
• The generating unit shall be capable of operating in the frequency range 47.5 to 52 Hz and shall be able to deliver rated output in the frequency range of 49.5 Hz to 50.5 Hz.be able to deliver rated output in the frequency range of 49.5 Hz to 50.5 Hz.
• Provided that in the frequency range below 49.90 Hz and above 50.05 Hz, or, as prescribed by the Central Commission from time to time, the output shall be as per frequency response requirement mentioned in sub- clause 4 below.
• Operating range of frequencies are consistent
Frequency Range & Active power control
The generating unit shall be capable of operating in the frequency range of 47.5 to 52 Hz and shall be able to deliver rated output in the frequency range of 49.5 Hz to 50.5 Hz.
The generating unit shall be capable of operating in the frequency range 47.5 to 52 Hz and shall be able to deliver rated output in the frequency range of 49.5 Hz to 50.5 Hz.be able to deliver rated output in the frequency range of 49.5 Hz to 50.5 Hz.
that in the frequency range below 49.90 Hz and above 50.05 Hz, or, as prescribed by the Central Commission from time to time, the output shall be as per frequency response
clause 4 below.
range of frequencies are consistent with IEGC regulations.
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Active power Control and Ramp
• Existing:
• Wind generating station connected at voltage level of 66 kV and above shall have facility to control active power injection in accordance with a set point, which shall be capable of being revised based on direction of the appropriate Load Dispatch Centre.
• Proposed:
• (a). Wind and Solar generating stations with installed capacity of more than 10 MW • (a). Wind and Solar generating stations with installed capacity of more than 10 MW connected at voltage level of 33 66 kV and above shall have facility to control active power injection in accordance with a set point, which shall be capable of being revised based on direction of the appropriate Load Dispatch Centre. the units shall have a droop of 3 to 6% and a dead band
• (b) The operating range of the frequency response and regulation system shall be from 10% to 100% of the maximum AC active power capacity.
• (c). The Wind and Solar generating unit shall be able to control the rate of change of power output at a rate not more than +meteorological conditions. The ramp rate control tolerance shall be
Active power Control and Ramp
Wind generating station connected at voltage level of 66 kV and above shall have facility to control active power injection in accordance with a set point, which shall be capable of being revised based on direction of the appropriate Load Dispatch Centre.
stations with installed capacity of more than 10 MW stations with installed capacity of more than 10 MW kV and above shall have facility to control active
power injection in accordance with a set point, which shall be capable of being revised based on direction of the appropriate Load Dispatch Centre. Governors of the units shall have a droop of 3 to 6% and a dead band not exceeding + 0.03 Hz.
The operating range of the frequency response and regulation system shall be from 10% to 100% of the maximum AC active power capacity.
The Wind and Solar generating unit shall be able to control the rate of change 10% per minute, independent of
meteorological conditions. The ramp rate control tolerance shall be +10%. 40
Active power Control and Ramp
• Provisos
• Provided that for large frequency deviation e.g. in excess of 0.3 Hz, the Wind and Solar Generating Station should provide an immediate( within 1 second) real power primary frequency response of at least 10% of the maximum AC active power capacity.
• Provided that wind generating station and inverter based generating stations having capacity 50 MW or more shall have storage capacity of at least 10% of installed capacity as common facility irrespective of generation capacity owned/ developed by different capacity 50 MW or more shall have storage capacity of at least 10% of installed capacity as common facility irrespective of generation capacity owned/ developed by different owners/developers .
• Provided further that if energy storage systems are utilized to comply with the frequency regulation requirements, and during a disturbance, the system frequency falls suddenly and stays below 49.7 Hz, the wind/solar generating station shall provide an immediate frequency response. The time response shall be less than 1 second and should be maintained for at least 10 minutes . After the 10frequency response should not decrease at a ramp rate higher than 10% of the maximum AC active power capacity per minute.
Active power Control and Ramp
Provided that for large frequency deviation e.g. in excess of 0.3 Hz, the Wind and Solar Generating Station should provide an immediate( within 1 second) real power primary frequency response of at least 10% of the maximum AC active power capacity.
Provided that wind generating station and inverter based generating stations having capacity 50 MW or more shall have storage capacity of at least 10% of installed capacity as common facility irrespective of generation capacity owned/ developed by different capacity 50 MW or more shall have storage capacity of at least 10% of installed capacity as common facility irrespective of generation capacity owned/ developed by different
Provided further that if energy storage systems are utilized to comply with the frequency regulation requirements, and during a disturbance, the system frequency falls suddenly and stays below 49.7 Hz, the wind/solar generating station shall provide an immediate frequency response. The time response shall be less than 1 second and should be
. After the 10th minute, the real power primary frequency response should not decrease at a ramp rate higher than 10% of the maximum
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Why Active power control and ramp control is required
• With more and more renewable generation capacity,conventional generation stations would be lessconventional units not working.
• If active power support is not available form renewableunder certain situations like sudden outage of units/linesunder certain situations like sudden outage of units/lines
• At present what is required is the ability , it may
• Downside capability is no issue, for upside capabilityoutput or Storage.
• Storage viability is to be seen.
Why Active power control and ramp control is
capacity, during the day , share of power from. Not sufficient inertia in the system due to many
renewable , it would be difficult to manage systemunits/lines.units/lines.
be operationalized based on system requirement.
capability two options operating at say 95% power
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Voltage RegulationVoltage RegulationVoltage RegulationVoltage RegulationFollowing new clause B2(5) is proposed to be added Regulation in Wind and Solar generating stations
a). Wind Generating stations/ Solar generating continuously-variable, continuously-acting, closed loop control Voltage Regulation System (VRS) i.e. an equivalent to the Automatic Voltage Regulator (AVR) in conventional machines.
b). The VRS set-point shall be adjustable in the range prescribed by the appropriate Commission and it shall also be adjustable by Load Dispatch Center via SCADA.
c). The VRS controller regulation strategy shall be based on proportional plus integral c). The VRS controller regulation strategy shall be based on proportional plus integral (PI) control actions with parallel reactive droop compensation. The VRS Droop shall be adjustable from 0 to 10%.
d). The VRS shall be calibrated such that a change in reactive power will achieve 95% of its final value no later than 1 second following a step change in voltage. The change in reactive power shall not cause excessive voltage excursions or overshoot.
e). The VRS shall be in service as long as the Wind / Solar generating unit is electrically connected to the grid, regardless of MW output including nil generation from the unit.
f). The VRS dead band shall not exceed + 0.1%.
Voltage RegulationVoltage RegulationVoltage RegulationVoltage Regulationis proposed to be added to incorporate feature of Voltage
Regulation in Wind and Solar generating stations:
Solar generating stations ( Solar Parks )shall have a acting, closed loop control Voltage Regulation System
(VRS) i.e. an equivalent to the Automatic Voltage Regulator (AVR) in conventional machines.
point shall be adjustable in the range prescribed by the appropriate Commission and it shall also be adjustable by Load Dispatch Center via SCADA.
The VRS controller regulation strategy shall be based on proportional plus integral The VRS controller regulation strategy shall be based on proportional plus integral (PI) control actions with parallel reactive droop compensation. The VRS Droop shall be
The VRS shall be calibrated such that a change in reactive power will achieve 95% of its final value no later than 1 second following a step change in voltage. The change in reactive power shall not cause excessive voltage excursions or overshoot.
The VRS shall be in service as long as the Wind / Solar generating unit is electrically connected to the grid, regardless of MW output including nil generation from the unit.
0.1%.
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Compliance Monitoring
The following new Regulation is proposed to be added
It shall be the responsibility of concerned Central/ State Transmission utility to ensure that before connectivity to grid is permitted, all general connectivity conditions stipulated in the CEA Regulations are general connectivity conditions stipulated in the CEA Regulations are complied with. Normally, it shall be in the form of selfthe proforma of connection agreement which can be sample checked/ verified by CTU/STU . Non compliance shall be reported immediately to appropriate commission.
Compliance Monitoring
proposed to be added
shall be the responsibility of concerned Central/ State Transmission utility to ensure that before connectivity to grid is permitted, all general connectivity conditions stipulated in the CEA Regulations are general connectivity conditions stipulated in the CEA Regulations are complied with. Normally, it shall be in the form of self-declaration in
of connection agreement which can be sample checked/ verified by CTU/STU . Non compliance shall be reported immediately to
Thank You Vikram Singh,
Director( Grid Management)
Central Electricity Authority
[email protected], [email protected]
9868898305145