Trimark provides technical solutions and services to enable grid stability for the electric industry. As renewable penetration increases, grid stability is becoming a larger issue. Utilities are requiring renewable power plants to provide more grid support through their agreements. This is driving the need for a power plant controller to mitigate grid stability issues by coordinating inverters and other devices to support functions like automatic voltage regulation, demand response, and frequency control. Meeting grid stability requirements directly impacts revenue and profitability, so understanding technical requirements and business implications is important.

1. For all your mission critical solutions –
we’ll be there!
Enhancing Grid Stability by Deploying
Advanced Inverter Control
May 10, 2016
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2. Trimark Overview
• Trimark delivers innovative technical soltions and and professional services that
enable operational excellence, safety and grid stability for the electric energy
industry.
• Facts and Figures:
• 250+ utility-scale development clients
• Manage data used to validate >$1 Billion in energy transactions
• 80 employees
• Offices in California and Virginia
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3. Increasing PV and Storage Penetration = Grid Stability Issues
• As states approach their Renewable Portfolio Standards goals, utilities are
learning the impacts of wide scale, distributed, generation on grid stability
• Initially ignored, grid stability caused by renewables and storage is
increasingly becoming an issue to be addressed
• Grid support features are being written in to Power Purchase Agreements
and Interconnection Agreements
• Grid support from renewable power resources is now an expectation
• The requirements will become more detailed and be more rigorously
enforced as more and more renewable resources join the grid at larger and
larger MW ratings
• This is driving the need for a Power Plant Controller (PPC) to mitigate grid
stability issues

4. Power Plant Control Functions to Support Grid Stability
Control Functions
InverterConnect/
Disconnect
MaxPowerGeneration
(WMax)
ClosedLoopSiteReal
Power
ClosedLoopSiteReactive
Power
ClosedLoopSitePower
FactorControl
AutomaticVoltage
Regulation/
CapacitorBankIntegration
Voltage-VAR
Compensation
FrequencyDroop
PowerFactor
Compensation
Compliance/BusinessImperative
Automatic Voltage Regulation 
Utility Demand Response      
Automatic Generation Control   
Active Power Optimization  
Power Quality Management      
Remote Device Control 

5. Grid Stability Issues and Solutions
Automatic Voltage Regulation
Utility Demand Response
Automatic Generation Control
Power Quality Management
Operational
Control

6. Automatic Voltage Regulation:
Dynamic reactive power
(VAR) must be managed to
follow the assigned voltage
schedule and minimize
voltage fluctuations at the
POI.
The PPC coordinates various devices (inverters
and static reactive devices) to ensure that
dynamic reactive power (VAR) follows the
assigned voltage schedule as measured at the
POI. The PPC adjusts inductive and capacitive
VARS at a defined ramp rate to minimize
voltage upsets at the POI.
Objective Function

7. Closed-Loop Automation: Grid Stabilization
Point of Interconnection
(POI)
Capacitor
Bank
Metered Power
Grid Disturbance:
Voltage Deviation
Automated Command:
Automated Voltage Regulation
Equipment Status and Control
Voltage Control
P
V
VARs
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8. Utility Demand Response:
The Resource must adjust
power characteristics at the
POI in response to an
authorized set point
command.
The PPC coordinates all device’s to deliver real
power and reactive power to meet a specific
set point (e.g. curtailment) provided by the ISO
or utility. Changes follow a defined ramp rate in
order to minimize voltage abnormalities at the
POI.
Objective Function

9. Curtailment from Authorized Entity
Point of Interconnection
(POI)
Metered Power
Balancing Authority,
Utility, or Op Center
Power Curtailed
Setpoint Command:
Curtail Power
P
Equipment Status and Control
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10. Automatic Generation Control:
Balancing authority
(Utility/ISO) may require the
Resource to adjust power at
the POI to balance load and
supply. (Automated Dispatch
Systems would send a
dispatch command.)
The PPC coordinates output from devices
(inverters/batteries) to follow a secure,
changeable command from an authorized
entity (host utility). The PPC ensures that
power delivered to the POI matches the
commanded setpoint.
Objective Function

11. Automatic Energy Generation
Point of Interconnection
(POI)
Equipment Status and Control
Metered Power
ALERT:
“Inverter
Fault!”
Automated Command:
Increase Generation
Stable Power at POI
P
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12. Power Quality Management:
Manage power quality
characteristics (e.g. VARs,
Power Factor, Apparent
power, and Frequency) at the
POI.
The PPC measures power characteristics at the
POI then manages devices to deliver the
desired power quality characteristic (e.g. VARs,
Power Factor, Apparent power, and Frequency)
at the POI. The system uses intelligent, real-
time closed-loop logic to conduct an ongoing
cycle of measure and adjust.
Objective Function

13. Why doesn’t every resource do this?
• Maintaining grid stability is a challenge.
• PV and wind power generation fluctuates
with weather changes.
• Storage system are designed to react quickly
to the changes.
• Electrical characteristics are affected by
resistance and losses.
• This adds difficulty to the effort of meeting
the power delivery schedule and delivering
the contracted power with the contracted
characteristics.

14. Will this affect my revenue stream?
• Yes, it can.
• Resources get paid based on real power.
• Adjusting voltage during a particular schedule
can affect real power delivered to the POI.
• Increasing reactive power can reduce the real
power, thereby lowering the settlement
value.
• Most power markets do not provide
compensation for delivering VARs.

15. How hard can it be?
• Requires experience with both PV controls
and electric power.
• Resources need a system to automate control over
generation and power quality at POI.
• Resources are challenged by complicated, evolving
PPA requirements.
• Markets do not provide incentives for
participating.
• Many power quality requirements are too
complicated and costly to implement.

16. Doesn’t my CAP bank do all that?
• No
• External set point changes can be and are
issued frequently (5 minutes).
• A PPC is required to intelligently invoke
the capabilities of inverters, capacitor
banks, reactors, and STATcoms to achieve
a common goal.
• The PPC coordinates the operation of all
these devices to achieve required power
characteristics in the most effective way.

17. How much revenue might I lose?
• Curtailment orders reduce generation.
• Resource owners need data to validate and
document utility curtailment orders and the
resulting loss in energy production.
• To protect their business interests, resource
owners must document curtailments and resulting
lost generation.
• Performance analysis must consider curtailments
in order to accurately understand de-rating.
• Manual documentation is not based on real-time
interval data. Calculations are labor intensive, error
prone, and often delayed.

18. Four Key Takeaways
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#1
Grid stability
mitigation is
increasingly
important to
electric utilities.
#2
Utilities are instituting
more mandatory
control requirements
now than in 2015.
#3
Mandatory controls
directly affect power
production and
profitability.
Imperative to
understand business
implications.
#4
Identify ALL technical
requirements of your
PPA and interconnect
agreements.

19. For all your mission critical solutions –
we’ll be there!
Questions?
www.TrimarkAssoc.com
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Dean Schoeder – DSchoeder@trimarkassoc.com