Slides from the June 6, 2016, webinar on Advanced WEC Dynamics and Controls, hosted by Sandia National Laboratories for the US Department of Energy. SAND2016-5473 PE
Voltage Sag Mitigation in Utility Connected System Using Current Source Conve...IDES Editor
This paper discusses the implementation of current
source converter based distribution type static synchronous
compensator. For eliminating the lower order harmonics, the
power semiconductors are switched by pulse width modulation
technique. Current source converter, input filter, dc link
reactor are combined to design the proposed CSC based
STATCOM. Since the STATCOM is a current injection
device, the performance of the device is improved by a currentsource
converter (CSC) combination. So a controllable current
is generated at the output terminals of the device. Filter circuit
at the input terminal is designed to eliminate the higher order
harmonics. The proposed D- STATCOM is simulated and the
results are validated using MATLAB.
A brief and basic presentation of interconnections of pwer system,it covers all the basic aspects of power system interconnection that how systems can be built with interconnections
These slides presents an overall discussion on fault location techniques generally used in present power transmission and distribution system. Later of the class we will discuss about the implementation principles and mathematical formulations.
Energy Management and the Evolution of Intelligent Motor Control and Drives @...ARC Advisory Group
Energy Management and the Evolution of Intelligent Motor Control and Drives @ ARC's 2011 Industry Forum by Craig Resnick.
Intelligent motor control & drives once provided a safe, flexible & centralized means to control & protect motors
•Today, these devices have evolved to ‘smart’ energy managers that bring advances ranging from complex drive systems to basic control of fan or pump motors
•In high demand where uptime & equipment reliability are critical, in applications where even a short period of downtime can prove extremely costly & damaging
•These devices perform critical protective & troubleshooting functions & detailed diagnostics to help improve productivity & minimize downtime
Test Operation Procedures for Electrical & Electronic Parameters of Solar Pho...AKASH BISWAS
The Solar Hybrid Inverter i.e. Solar Inverter plus the
Charge Controller is a prominent and revolutionary part of the
newly added Solar Power Packs (AC Model – I,II,III) to the Solar
Photovoltaic Testing standard of the Ministry of New and
Renewable Energy (MNRE) for OFF-grid solar application
scheme, 2016-2017. This paper presents the procedures and
subjective analysis of the measurements carried out on the hybrid
solar inverter as well as the solar system which includes the
inverter on different parameters such as Total Harmonic Distortion
(THD), Battery Low-Voltage Cut-off, Load Reconnect, Overcharge
Cut-off, Electronic Efficiency etc. Apart from the protection
parameters and the inverter efficiency test a study of the Battery
Capacity (100% Capacity & Depth of Discharge (DOD)) which
powers the inverter has been done. A brief discussion on battery
capacity testing techniques has been provided to conclude the
paper.
Monitoring of Lead Acid Batteries - an Eltek White PaperEltek
Eltek's Gunnar Hedlund demonstrates different methods of predicting premature capabity loss in your battery park.
No foolproof indicators/tools for knowing and predicting the health and life of a lead acid battery have been evolved or devised. The only way to truly determine the health of a standby lead-acid battery is to perform a 100 % capacity test, according to the battery manufacturers discharge table.
Such a capacity test means that the battery needs to be disconnected from the load and another back-up battery connected when the capacity test is performed. However, comprehensive controllers and instruments are now able to find failing cells without this test and while the battery system is online.
A large number of techniques have been explored and tried out in the field. No single method or test instrument is capable of foolproof prediction about the residual capacity without performing a 100% capacity test. On the other hand, by combining some of them the state of health and expected residual life of the battery can be predicted more precisely and reliably. This is especially true in the finding of failing cells in a standby lead-acid battery.
Presentation from the EPRI-Sandia Symposium on Secure and Resilient Microgrids: Empowering Clean Energy, presented by Adib Nasle, XENDEE, Baltimore, MD, August 29-31, 2016.
Slides from the June 6, 2016, webinar on Advanced WEC Dynamics and Controls, hosted by Sandia National Laboratories for the US Department of Energy. SAND2016-5473 PE
Voltage Sag Mitigation in Utility Connected System Using Current Source Conve...IDES Editor
This paper discusses the implementation of current
source converter based distribution type static synchronous
compensator. For eliminating the lower order harmonics, the
power semiconductors are switched by pulse width modulation
technique. Current source converter, input filter, dc link
reactor are combined to design the proposed CSC based
STATCOM. Since the STATCOM is a current injection
device, the performance of the device is improved by a currentsource
converter (CSC) combination. So a controllable current
is generated at the output terminals of the device. Filter circuit
at the input terminal is designed to eliminate the higher order
harmonics. The proposed D- STATCOM is simulated and the
results are validated using MATLAB.
A brief and basic presentation of interconnections of pwer system,it covers all the basic aspects of power system interconnection that how systems can be built with interconnections
These slides presents an overall discussion on fault location techniques generally used in present power transmission and distribution system. Later of the class we will discuss about the implementation principles and mathematical formulations.
Energy Management and the Evolution of Intelligent Motor Control and Drives @...ARC Advisory Group
Energy Management and the Evolution of Intelligent Motor Control and Drives @ ARC's 2011 Industry Forum by Craig Resnick.
Intelligent motor control & drives once provided a safe, flexible & centralized means to control & protect motors
•Today, these devices have evolved to ‘smart’ energy managers that bring advances ranging from complex drive systems to basic control of fan or pump motors
•In high demand where uptime & equipment reliability are critical, in applications where even a short period of downtime can prove extremely costly & damaging
•These devices perform critical protective & troubleshooting functions & detailed diagnostics to help improve productivity & minimize downtime
Test Operation Procedures for Electrical & Electronic Parameters of Solar Pho...AKASH BISWAS
The Solar Hybrid Inverter i.e. Solar Inverter plus the
Charge Controller is a prominent and revolutionary part of the
newly added Solar Power Packs (AC Model – I,II,III) to the Solar
Photovoltaic Testing standard of the Ministry of New and
Renewable Energy (MNRE) for OFF-grid solar application
scheme, 2016-2017. This paper presents the procedures and
subjective analysis of the measurements carried out on the hybrid
solar inverter as well as the solar system which includes the
inverter on different parameters such as Total Harmonic Distortion
(THD), Battery Low-Voltage Cut-off, Load Reconnect, Overcharge
Cut-off, Electronic Efficiency etc. Apart from the protection
parameters and the inverter efficiency test a study of the Battery
Capacity (100% Capacity & Depth of Discharge (DOD)) which
powers the inverter has been done. A brief discussion on battery
capacity testing techniques has been provided to conclude the
paper.
Monitoring of Lead Acid Batteries - an Eltek White PaperEltek
Eltek's Gunnar Hedlund demonstrates different methods of predicting premature capabity loss in your battery park.
No foolproof indicators/tools for knowing and predicting the health and life of a lead acid battery have been evolved or devised. The only way to truly determine the health of a standby lead-acid battery is to perform a 100 % capacity test, according to the battery manufacturers discharge table.
Such a capacity test means that the battery needs to be disconnected from the load and another back-up battery connected when the capacity test is performed. However, comprehensive controllers and instruments are now able to find failing cells without this test and while the battery system is online.
A large number of techniques have been explored and tried out in the field. No single method or test instrument is capable of foolproof prediction about the residual capacity without performing a 100% capacity test. On the other hand, by combining some of them the state of health and expected residual life of the battery can be predicted more precisely and reliably. This is especially true in the finding of failing cells in a standby lead-acid battery.
Presentation from the EPRI-Sandia Symposium on Secure and Resilient Microgrids: Empowering Clean Energy, presented by Adib Nasle, XENDEE, Baltimore, MD, August 29-31, 2016.
Presentation from the EPRI-Sandia Symposium on Secure and Resilient Microgrids: Microgrid Design Toolkit, presented by John Eddy, Sandia National Laboratories, Baltimore, MD, August 29-31, 2016.
Presentation from the EPRI-Sandia Symposium on Secure and Resilient Microgrids: Micro grid design: Considerations & interconnection studies, presented by Mobolaji Bello, EPRI, Baltimore, MD, August 29-31, 2016.
Presentation from the EPRI-Sandia Symposium on Secure and Resilient Microgrids: Simulation & Analysis Tools for Microgrids, presented by Dean Went and Andre Cortes, EPRI, Baltimore, MD, August 29-31, 2016.
Presentation from the EPRI-Sandia Symposium on Secure and Resilient Microgrids: Microgrid Market Operations with Distribution System Operators, presented by Mohammad Shahidehpour, Baltimore, MD, August 29-31, 2016.
HVDC stands for high voltage direct current, a well-proven technology used to transmit electricity over long distances by overhead transmission lines or submarine cables. It is also used to interconnect separate power systems, where traditional alternating current (AC) connections cannot be used.
The 7PG21 is a three phase unit differential protection used to detect in zone phase and earth faults. The relay is applied to overhead line and underground cable circuits as well as shorter circuits such as interconnectors.
Relays (and associated CTs) are installed at each end of the protected circuit and connected together with dedicated metallic pilot wires.
Electrical Power System Management becomes an important aspect when it comes to Deregulated market comprising of Generation, Transmission and Distribution. It gives basic understanding of the principles of Power System operation like Voltage Control, etc.
An inverter is an electric apparatus that changes direct current (DC) to alternating current (AC). It is not the same thing as an alternator, which converts mechanical energy(e.g. movement) into alternating current.
Direct current is created by devices such as batteries and solar panels. When connected, an inverter allows these devices to provide electric power for small household devices. The inverter does this through a complex process of electrical adjustment. From this process, AC electric power is produced. This form of electricity can be used to power an electric light, a microwave oven, or some other electric machine.
It is very useful power point presentation on the "Grid Voltage Regulation"
it consist all thing related with topic.
I have already presented and got 100% credit.
An inverter is an electric apparatus that changes direct current (DC) to alternating current (AC). It is not the same thing as an alternator, which converts mechanical energy(e.g. movement) into alternating current.
Direct current is created by devices such as batteries and solar panels. When connected, an inverter allows these devices to provide electric power for small household devices. The inverter does this through a complex process of electrical adjustment. From this process, AC electric power is produced. This form of electricity can be used to power an electric light, a microwave oven, or some other electric machine.
These slides present about islanding detection techniques in microgrid systems. Later on the classes other aspects of microgrid protection will be discussed in more detail
Similar to 2014 PV Distribution System Modeling Workshop: Interaction and Coordination with EPS Equipment: Chase Sun, PG&E (20)
Up the Ratios Bylaws - a Comprehensive Process of Our Organizationuptheratios
Up the Ratios is a non-profit organization dedicated to bridging the gap in STEM education for underprivileged students by providing free, high-quality learning opportunities in robotics and other STEM fields. Our mission is to empower the next generation of innovators, thinkers, and problem-solvers by offering a range of educational programs that foster curiosity, creativity, and critical thinking.
At Up the Ratios, we believe that every student, regardless of their socio-economic background, should have access to the tools and knowledge needed to succeed in today's technology-driven world. To achieve this, we host a variety of free classes, workshops, summer camps, and live lectures tailored to students from underserved communities. Our programs are designed to be engaging and hands-on, allowing students to explore the exciting world of robotics and STEM through practical, real-world applications.
Our free classes cover fundamental concepts in robotics, coding, and engineering, providing students with a strong foundation in these critical areas. Through our interactive workshops, students can dive deeper into specific topics, working on projects that challenge them to apply what they've learned and think creatively. Our summer camps offer an immersive experience where students can collaborate on larger projects, develop their teamwork skills, and gain confidence in their abilities.
In addition to our local programs, Up the Ratios is committed to making a global impact. We take donations of new and gently used robotics parts, which we then distribute to students and educational institutions in other countries. These donations help ensure that young learners worldwide have the resources they need to explore and excel in STEM fields. By supporting education in this way, we aim to nurture a global community of future leaders and innovators.
Our live lectures feature guest speakers from various STEM disciplines, including engineers, scientists, and industry professionals who share their knowledge and experiences with our students. These lectures provide valuable insights into potential career paths and inspire students to pursue their passions in STEM.
Up the Ratios relies on the generosity of donors and volunteers to continue our work. Contributions of time, expertise, and financial support are crucial to sustaining our programs and expanding our reach. Whether you're an individual passionate about education, a professional in the STEM field, or a company looking to give back to the community, there are many ways to get involved and make a difference.
We are proud of the positive impact we've had on the lives of countless students, many of whom have gone on to pursue higher education and careers in STEM. By providing these young minds with the tools and opportunities they need to succeed, we are not only changing their futures but also contributing to the advancement of technology and innovation on a broader scale.
Presentation by Jared Jageler, David Adler, Noelia Duchovny, and Evan Herrnstadt, analysts in CBO’s Microeconomic Studies and Health Analysis Divisions, at the Association of Environmental and Resource Economists Summer Conference.
Jennifer Schaus and Associates hosts a complimentary webinar series on The FAR in 2024. Join the webinars on Wednesdays and Fridays at noon, eastern.
Recordings are on YouTube and the company website.
https://www.youtube.com/@jenniferschaus/videos
Russian anarchist and anti-war movement in the third year of full-scale warAntti Rautiainen
Anarchist group ANA Regensburg hosted my online-presentation on 16th of May 2024, in which I discussed tactics of anti-war activism in Russia, and reasons why the anti-war movement has not been able to make an impact to change the course of events yet. Cases of anarchists repressed for anti-war activities are presented, as well as strategies of support for political prisoners, and modest successes in supporting their struggles.
Thumbnail picture is by MediaZona, you may read their report on anti-war arson attacks in Russia here: https://en.zona.media/article/2022/10/13/burn-map
Links:
Autonomous Action
http://Avtonom.org
Anarchist Black Cross Moscow
http://Avtonom.org/abc
Solidarity Zone
https://t.me/solidarity_zone
Memorial
https://memopzk.org/, https://t.me/pzk_memorial
OVD-Info
https://en.ovdinfo.org/antiwar-ovd-info-guide
RosUznik
https://rosuznik.org/
Uznik Online
http://uznikonline.tilda.ws/
Russian Reader
https://therussianreader.com/
ABC Irkutsk
https://abc38.noblogs.org/
Send mail to prisoners from abroad:
http://Prisonmail.online
YouTube: https://youtu.be/c5nSOdU48O8
Spotify: https://podcasters.spotify.com/pod/show/libertarianlifecoach/episodes/Russian-anarchist-and-anti-war-movement-in-the-third-year-of-full-scale-war-e2k8ai4
What is the point of small housing associations.pptxPaul Smith
Given the small scale of housing associations and their relative high cost per home what is the point of them and how do we justify their continued existance
Canadian Immigration Tracker March 2024 - Key SlidesAndrew Griffith
Highlights
Permanent Residents decrease along with percentage of TR2PR decline to 52 percent of all Permanent Residents.
March asylum claim data not issued as of May 27 (unusually late). Irregular arrivals remain very small.
Study permit applications experiencing sharp decrease as a result of announced caps over 50 percent compared to February.
Citizenship numbers remain stable.
Slide 3 has the overall numbers and change.
A process server is a authorized person for delivering legal documents, such as summons, complaints, subpoenas, and other court papers, to peoples involved in legal proceedings.
3. Protection
• Run fault studies with inverter modelled and with the inverter
contribution.
• Set each inverter to trip for end of line fault if possible. Conventional
overcurrent settings may not be adequate for variable resources such as
PV inverters since the settings may be too high when the PV output is low
in the morning and in the late afternoon. Often, the inverters are set up
for sequential tripping, using anti-islanding, after the feeder tripped first.
• Check to make sure that the inverter will not trip for adjacent feeder faults
that should be cleared by the adjacent feeder breaker.
• Check the existing feeder protective device settings for relays, reclosers,
interrupters, fuses, to make sure the existing relay settings are still
adequate with the inverter contribution. In other words, make sure the
devices will not be de-sensitized by a significant amount as to not trip for
an in-section fault. This is not usually an issue due to the low inverter
fault duty.
3
4. Protection
• Check that the additional inverter fault duty will not
overstress existing equipment. This is usually not an
issue due to the low inverter fault duty.
• In general, each protective device, including inverters,
should trip for faults within its protected section and
not trip for faults outside of its protection zone. This is
problematic since the existing inverters are set up for
low penetration mode and may overtrip.
• At high penetrations, the inverter should not trip for a
system-wide event and aggravate the severity of the
event. This is being addressed in the Phase 1 revised
trip settings.
4
5. Voltage interaction/coordination
Background
• Main issues:
• Traditionally, generators were connected to the transmission system, designed for
multi-directional flow where the conductors are much bigger and sized for both
local load and loop flow. Also, the transmission system is not regulated as tightly
as the distribution system.
• Distribution system was designed in a radial tree configuration, to distribute power
at the lowest cost. So, the distribution feeder mainline is composed of big
conductors, similar to a tree trunk, and the branch conductors are sized for local
load but not capable of carrying current for any significant distance without severe
voltage drop.
• For example, on the PG&E system, less than 15% of the overall distribution
conductor population are large mainline conductors sized at 397 MCM or larger.
PVs connected to large mainline conductors have minimal voltage impact to other
customers. But more than 85% of the locations have smaller conductors with
various degrees of voltage impact. The worst cases are larger units at the end of
small feeder conductors. In the interconnection studies, once the feeder is
reconductored, the voltage issues usually go away.
• PG&E has approximately 140,000 circuit miles of distribution conductors. it costs
about $500,000/mile to replace the conductor to 397 MCM or larger.
5
6. Voltage interaction/coordination
Background
As a frame of reference, we can look at the current load review process:
• The distribution loads are reviewed during load interconnection to insure
that the load switching will not cause excessive voltage fluctuation to
other customers.
• CA Rule 2 limits the largest single phase 240V motor that can be started
across the line to 7.5 HP and the largest 480V, 3 phase motor that can be
switched across the line to 100 HP.
• Rule 2, Sec D3d states that for its operating convenience and necessity,
PG&E may elect to supply an applicant whose demand load is in excess of
2,000 kVA from a substation on the customer premises supplied from a
transmission source.
• Load has diversity that is well understood and utilized by the operating
utilities.
6
7. Voltage interaction/coordination
Background
• The distribution system is also regulated to +/-5% of nominal
voltage by radial tap changing voltage regulators to provide the
proper utilization voltage to the distribution customers.
• The tap changing voltage regulators are not effective in regulating
voltage in the reverse direction when DG is present.
• The existing E/M regulators used time delays to coordinate
operation between multiple regulators. Since these are E/M
regulators, it takes time to change taps. Typically, there is about 20-
45 second time delay between regulators to insure the upstream
regulator is done with its correction before the next stage regulator
operates. Setting the time delays too close may cause hunting and
unstable operation between the regulators.
7
8. Voltage Regulation
• There are no specific operational provisions for voltage rise due to DG in
Rule 21. For example, if the feeder is operating at 126V at peak already, as
allowed by Rule 2, there is no room for DG voltage rise. The good thing is
that PV peaks at noon and the feeders typically peak at 4-6 PM when the
PV output is much lower. At noon, the feeder voltage is typically not at
126V and there is more room for DG voltage rise. Please note that the
higher trip set point of 132 V specified in Rule 21 is intended to cover
voltage rise within the customer facility and not intended to allow the DG
to cause voltage beyond the PCC to operate at 132V.
• When Conservation Voltage Regulation (CVR) program is present, the
required operating voltage is restricted to +0% and -5% range which
further reduce the available DG operating voltage margin.
• Typically, the distribution engineer make adjustments in the voltage
regulator settings, when possible, to accommodate the DG voltage rise.
Often this reduces the operating flexibility of the distribution feeder.
8
9. Voltage regulation
• DGs are generation sources and will cause voltage to rise in order to
push out the rated power.
• DGs are located on the load side of the voltage regulators and may
render the regulators ineffective.
• DGs are intermittent and not dependable from a capacity
perspective.
• PV also does not have that much diversity when it comes to cloud
cover effects. When a cloud cover comes over, the PV output may
drop from 100% down to 20% within seconds. For a storm cloud,
the drop may go lower.
• PV and wind output fluctuations may occur much faster than the
E/M voltage regulators can respond. Without mitigation, this may
reduce the power quality on the existing feeders and may have the
potential to damage customer equipment.
9
10. Conventional voltage mitigation
• Reset LTC and voltage regulators, where possible, to allow more margin for the
inverters to operate.
• Replace radial regulator control to bi-directional control and set in Cogen Mode.
Bi-directional mode is intended for radial feed from a back-up feeder and not
intended for DG.
• Remove Load Drop Compensator setting and use flat voltage regulation and install
additional voltage regulators as needed.
• Re-design the LTC control circuit to allow proper voltage on the other feeders.
• Install large PV on dedicated feeders to minimize impact on load customers that
require +/-5% voltage regulation. This is how PG&E designed its own large PV
installations.
• Connect larger PV to the mainline, large conductors, and close to the substation.
• Reconductor the small wires causing the voltage violations. This is the most
effective and simplest but sometimes the most expensive option
• Relocate voltage regulators and capacitors to account for the prevailing DG
outputs.
10
11. Potential smart inverter mitigations
• Note: The discussion below is relevant to larger inverters.
Volt/var control with small inverters may not be effective
since they may not be able to buck the system to any
significant extent. Also operating the feeder at off-unity PF
may increase the line current and increase line losses.
• High voltage due to PV reverse flow
– Set inverter at lagging PF to drag voltage down. This mode is
not considered active voltage regulation and is allowed under
the current Rule 21 and IEEE-1547. But this may require
installation of capacitors elsewhere to make up for the lost vars
to avoid voltage problems elsewhere.
– Reduce output at unit PF to maintain voltage below limits. This
may be viable for occasional overvoltage conditions.
11
12. Smart Inverter Voltage Enhancements
• Other voltage control opportunities also exist
and should be explored.
12
13. Active volt/var control issues
• Autonomous active volt/var control using local voltage feedback needs to
be coordinated carefully when there are multiple active control inverters
in the vicinity. If not coordinated properly, this may lead to the devices
fighting each other and potentially worse voltage on the feeder. This is
still an evolving area that needs more study.
• Communication based active volt/var control may be much simpler since
the central control computer can dictate which unit is in control at any
given time. But this may require a real time smart grid computer and an
extensive communication infrastructure, which do not exist at this time.
– Local master slave set-up is also possible with radio communication between the units.
13
14. Potential ways to avoid/minimize inintended interaction
between autonomous active control inverters:
• Defined ramp up of var absorption rate when voltage goes over a preset
level to help reduce the local voltage.
• Defined ramp up of var injection when voltage goes below a preset level
to help raise the local voltage.
• Include deadbands to de-sensitize the inverter response
• Define time delay between specific inverters to allow one inverter to
complete its control action before the next inverter act.
• The inverter can respond much quicker than the voltage regulators when
the voltage is outside of the deadband. So, it would be desirable to have
the inverter complete its active voltage control action before the voltage
regulators respond. This may also minimize the regulator response and
reduce the wear and tear on the regulators.
• Set a large inverter to active volt/var control and disable the active
volt/var on the smaller units to avoid complications
14
15. Outstanding high penetration issues
• Scenario 1: When there is a large amount of DG on the feeder that
displaced load normally, and there is a momentary fault on the
feeder. The feeder breaker will trip to clear the fault and all of the
DG are required to de-energize the line for safety reasons. On the
PG&E system, the feeder breaker is typically designed to reclose in
5 seconds to test the line. If the momentary fault cleared, the
feeder will be energized. But at that time, the DGs will be off and
the regulator will be seeing much higher load but it will not respond
until the time delay period expired. So, the effect is the same as a
large load switching in together. In that time frame, the customers
may experience low voltage due to the higher load. Without the DG
being there, there will not be any load masking and the regulator
will be set for the correct load level before and after the fault.
• A possible mitigation is to decrease the inverter re-energizing time
to minimize the time that the customers experience low voltage.
15
16. High Penetration Issues
• Scenario 2: When there is a close-in adjacent feeder
fault, the bus voltage may sag to close to zero. The
current UV setpoint is 0.16 second at <50% voltage.
But the feeder breaker may not trip for more than 0.25
sec and all of the DG tied to that bus will trip
unnecessarily due to the current Rule 21 and IEEE-1547
setting. The sudden loss of a large amount of DG
capacity may also lead to low voltage conditions for the
load customers on the unfaulted feeder, until the
voltage regulation equipment can respond.
• The mitigation is presented in the Phase 1 UV settings
where we extended the time delay to 1 second for UV
<50% voltage.
16