INCREASE Project Presentation · •Questionnaire to gather the insight on challenges and solutions...

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INCREASE Project Presentation

Joint Project Workshop

19. March 2015, Aachen, Germany

Prof. dr. Andrej Gubina

University of Ljubljana, Slovenia

Andreas Tuerk, MBA

Joanneum Research


Overview

• Overview of the role of the DSO

• Feedback and results of DSO questionnaire carried out last year

• Progress of the proposed solution referring to results presented in several Deliverables

• Mapping to 10 questions


Overview of the role of the DSO

• In INCREASE, the DSO: • Is the facilitator of the INCREASE solutions • Is one of the key beneficiaries of the results • Provides key inputs and comments to the development • Field test cases in 4 DSO networks

• Envisioned impact on DSO: • Smart inverters provide services to them • Designed control tools utilize Smart Grid infrastructure • Evaluation of possible commercial roles of DSO • Regulatory barriers identified and addressed • Additional light shed into risk management questions:

• Upgrade the grid or operate closer to limits, actively?


Overview






Practical challenges and solutions from the DSO perspective

• Questionnaire to gather the insight on challenges and solutions • Questions covered four key DN issues of INCREASE project:

voltage control, voltage unbalance mitigation, line congestion mitigation and reserve provision.

• We have received responses from Austria, Belgium, Denmark, Italy, Slovenia, Spain and Sweden.

• The aspects investigated covered • Technology challenges (planning, operation and

measurement issues), • Proposed solutions (control strategies and topology),

financial support for AS and the • Regulatory framework issues.


Questionnaire

Technology challenges Policy aspects

Solutions for preventing voltage-unbalance problems

Are any of the AS specified in the DSO Grid Code?

Kind of reactive power control mechanisms integrated in the power plant that the DSO can prescribe

Specific aspects of market provision of the AS (for voltage and reserve provision) to be taken into account

Operation issues Measurement issues

Requirements on frequency-dependable reduction of real-power

DSO ability to prescribe an interface for real power reduction and access to other measurements

Requirements for real-power reduction dependent on measurement voltage

Measurements currently available in the LV and MV network

Stipulated power factor range for distributed generators

Additional measurements to be installed in the near future

Control curves that can be stipulated by the DSO


Overview






LV Distribution Networks

8

• Distribution grid originally designed for consumption

• Objectives: • Voltage criterion in accordance to EN 50160 (UΝ ±10 %)

• Compensation for the voltage drop in the power line

• Stationary adjustment to the ratio at the transformer (on-load ?)

• .

Source: Dr. Bernhard Ernst, EPIA-EDSO for Smart Grids Conference on Grid Management, 24 June 2014, Brussels, Belgium


Major Challenges: Transition from a downstream unidirectional to a bidirectional power scheme

Overvoltage and possible violation of EN 50160 • Limiting the capacity for DG

Other Technical Issues: Traditionally not monitored and/or controlled

Other operational issues • DG units not uniformly distributed to the three phases • Considerable voltage unbalances • Congestion issues on power lines and/or on transformers


9

Source: Dr. Bernhard Ernst, EPIA-EDSO for Smart Grids Conference on Grid Management, 24 June 2014, Brussels, Belgium



10

• Possible Solutions: • Reinforcement of the DN feeders

• Implementing electric energy storage

• Needs investments

• Use of OLTCs or/and voltage regulators • Needs investments

• Reliability issues

• Operational limitations

• Reactive power support • Limited by inverter rated power

• Inefficient for LV networks with high R/X ratio

• Increasing network losses

• Active power curtailment


INCREASE Issues Tackled

Grid support:

• Voltage control

• Over- and undervoltages

• Voltage unbalance

• Line congestion

• Provision of reserve

• Ancillary services:

– Towards DSOs & TSOs

– Voltage control

– Provision of reserve

– The ancillary service market

• The regulatory framework

• Market models

Technical: Beyond technicalities:

For the low and medium voltage grid

Focus on the low voltage grid


WP 3

WP 5

Framework conditions

Analysis to evaulate benefits

Results

KPIsCBA

SWOT+RA

MarketsProposed AS

Bussiness cases

WP 2Technology

Control strategy

Results

Finding the value in the services provided


INCREASE Solution Multi Agent Structure Control

Local control

Overlaying control

Scheduling control Service layer

Middleware layer

Physical layer DRES

LC

DRES

LC

LOAD … …

Real-time line rating Demand-side management

Forecasting tools Active network management

Multi-objective optimisation

AS market Electricity

market

Agent

Aggregator


The INCREASE Control Schemes

14

• Objectives: • Increase the penetration of DG units in existing

networks • Active management of LV distribution networks via a

distributed multi-agent systems • Enhance the observability and controllability of LV

networks • Facilitating DNOs transition to DSOs

• Control Schemes: • Local Control • Overlaying Control • Scheduling Control


Local Control Overview

15

• Objectives: Real time mitigation of overvoltages and of voltage unbalances • Low-level control scheme

• Stand-alone operation, use of local parameters (e.g. voltage at the PCC)

• Immediate reaction on changes of grid operational state • Enhancing the smooth/safe operation of the distribution grid

• Implementation: • Applied to DG units via INCREASE developed controllable grid-interfaced inverters

• Two basic control schemes are incorporated: droop control and voltage unbalance mitigation

• Conclusions: • INCREASE Local Control scheme: combines

• Droop control scheme reduces overvoltages efficiently, but not voltage unbalances

• Unbalance control scheme tackles asymmetries but cannot control overvoltages

• The voltage profile along the feeder is actively controlled.

• Unacceptable overvoltages avoided by curtailing part of injected real power of DG units • The total injected real power, in cases of high DG injection, is increased

• Higher penetration of DG units is feasible

• Voltage unbalances are considerably mitigated


Overlaying Control Overview

16

• INCREASE Local Control • Unequal active power curtailment among DG units of

the same feeder

• Overlaying Control (OC) • Based on a Multi-Agent System (MAS) • To effectively redistribute curtailed power to DG units, • According to their rated power

• Simulation results of OC: • May result in higher active power curtailment • Increased fairness compared to Local Control)

• Different policies of DSOs can be integrated in OC scheme

16



Objective: Uniform active power curtailment among DG units of the same feeder

Conceptual design: • 15 minutes timeslot • First 5 minutes: Only Local Control • Remaining 10 minutes: Activation of

Overlaying Control

Implementation: • Distributed Multi-Agent System (MAS) • Hierarchical Architecture (Agent-Aggregator) • An Agent in each controllable DG unit • Aggregator is usually sited at the DSO • Wired or Wireless communication between

Agents and Aggregator

17

Overlaying control

Local control

t+15 min t

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Main procedure: 1. Each agent messages the aggregator

• Injected active power • Voltage at the connection point

2. The aggregator agent checks uniform

power curtailment along a feeder

3. In case of uniform curtailment, DG units are only locally controlled.

4. If not, taking into account the network configuration and the rated power of the DG units, new set-points are calculated, corresponding to new droop curves for each DG unit and are communicated to local agents

5. Thus, a uniform active power curtailment is achieved according to the rated power of the DG units



Remarks: • Overvoltage mitigation is achieved

• Voltage profile is continuously

controlled by Local/Overlaying control

• Both controls result in similar voltage

profile along the feeder

• There is a margin between the feeder maximum voltage after the Overlaying control and the upper voltage threshold of 1.1 pu (as defined by EN 50160)

• Thus, there is a potential for further increasing active power injection

19 19

1 2 3 4 5 6 7

1.05

1.06

1.07

1.08

1.09

1.1

1.11

1.12

Nodes

Positiv

e S

equence V

oltage M

agnitude (p

u)

Without control

Only Local

Overlaying-Local

Upper threshold (EN 50160)


Scheduling Control Overview

20

• Overlaying control (OC) agents • Take care of individual feeders

• No PQ violations

• Scheduling control (SC) • Optimizes operating schedule

of DR in regulation zone

• Provides link to markets

• Coordinates other MAS levels


Scheduling Control: Expected Benefits to the DSO

21

• Expectations: • Optimal DRES energy injection enabled

• DR schedules are optimized based on market signals

• DSO will: • Encounter fewer congestions and voltage problems –

reduced need to invest in network upgrade

• Retain the final word over operating schedules via „traffic light“ mechanism OCA DRES


Scheduling Control Model

Model optimizes schedule of DR units

Demand response algorithm (incl. predicted grid constraints)

Power flow analysis +

Schedules of DR units

Flexibility information

No Yes

Real Time

Market data (pricing, etc.)

Topology, day-ahead forecasts

Day Ahead

Overlay Control

Local Control

Production and consumption profiles


Implemented solution Assumptions

• Step 1: Calculate optimal DR schedule (day-ahead) • Inputs (current, forecast)

• DR units parameters (e.g. Power, Energy, ToU, Flexibility).

• Approximate grid topology

• Market data (e.g. day-ahead market prices)

• Unmetered demand pattern

• PV power production

• Output: DR unit schedule for day-ahead

• Step 2: Checking of viability of the DR schedule • Via the power flow analysis

• Depending on the results, we either • Reiterate the DR algorithm or

• Send the DR schedule to the next time layer.


Flexible Energy Product

• Flexibility: defined as a property or behaviour. • Hard to quantify and to monetize this way

• We need a product!

• Flexible Energy Product (FEP) • Product +

• Stakeholders (supplying, receiving) +

• Market (open, tender…) =

• = Service

• Provided by various providers, including DG, DR and DRES (with forecasting)

• Can be sold on the markets



• FEP parameters • Internal price of the providing unit.

• Time of provision (cumulative duration, time of day)

• Ramping capability (ramp rates, dwell times,break points, etc.)

• Power

• Energy


Connection of WP3 Results to Markets

Scheduling Control DR


Overlaying Control DRES

Energy

Reserve Markets t > 7 d

Reserve Energy Product

Balancing Market 15 min < t < 30 min

Energy Product

Intraday Market 1 h < t < 24 h

Energy Product

Day-ahead Market 1 d < t < 7 d

Energy Product

Local Control DRES

VC, VUM, LCM

TSO

DSO

INCREASE Services Markets Stakeholders

TSO

DSO

Co

nsu

me

rs,

Co

mm

erc.

en

tity


INCREASE WP4 Field Trials

• Implementation of the INCREASE solutions in real-life network

• Four distribution networks in four different EU countries: • Austria (Energienetze Steiermark)

• Belgium (Eandis)

• Slovenia (Elektro Gorenjska)

• Netherlands (Alliander)

• Various operating issues

• Different network properties

• Wide range of possibilities for future implementation of the INCREASE solutions


INCREASE WP4 Field Trials

Field test scenario Austria the Netherlands Slovenia Belgium

OLTC control x x

DRES droop control x x x

Voltage unbalance control x

OLTC remote control x x

Technical Fairnes curtailment x

DRES coordinated control

(congestion management) x

DRES and OLTC coordinated

control x

Local control

Overlaying control


WP 5 Analysis Framework

Boundary conditions Analysis

INCREASE Technology

MAS control strategies

ProductsFlexible Energy Product

Stakeholders- Regulated: DSOs, TSOs- Commercial: DRES operators, Demand Response, aggregators

Services - DSO/TSO level- Existing/New

Markets- Day-ahead- Intra-day- Balancing- Reserve

Value Analysis

Assumptions- Analysis scenarios- Business cases- Measurements- Regulatory framework

Proposed improvements- Regulatory framework- Market framework

Results - Within current/improved framework- With current/new services

Assessment tools & KPIs - CBA, SWOT, Risk Analysis


Overview






Question 1

• Consider the most relevant outputs of your project for DSOs. When you expect these solutions (concepts or technical solutions) to be feasible and profitable for DSOs compared to passive network design? • Key INCREASE outputs:

• Technology (3phase inverters)

• MAS – control strategies

• Products: Flexible Energy Product -> services: 4 key services

• Regulatory + market improvements

• Feasible and profitable: • When the penetration of RES (especially solar PV) is high

enough.

• Simulation scenarios assume above 40% PV penetration in the rural DN.


DSO Cost Optimization


Question 1

5 10 15 20

very passive

active

some active elements

passive

very active

today short mid long

3 phase inverters

Multi Agent System (MAS)

years


Question 1a

• Feasibility and profitability: Explain what critical factors must be fulfilled. • Feasibility and economic evaluation: WP5 analysis

• Profitability: issues to consider

• DSO will always compare any solution to passive network reinforcement (a one-time expense). • DSOs will need to optimize between both extreme strategies.

• Part of the risk management when operating closer to the margins

• Is DSO expected to pay for the new services? • Demand response flexibility payment

• Green energy curtailment: • Proposed in INCREASE

• Choose the most cost efficient curtailment strategy

• Regulatory aspects • How much of costs could be passed through to consumers?


Question 1b

• Scale of solutions: • first trials, forefront DSO,

• Only where there is • Large enough penetration of DRES,

• Regulation to enable operation of DR, and

• AMI and smart meter infrastructure to enable MAS.


Question 1b

• Coordination of control interests is optimized based on total welfare for the society. • KPIs: total welfare is beyond INCREASE, as we would

need a macroeconomic model of the society for this.

• No CBA in INCREASE

• DSO: if total welfare is defined as social optimum, • DSOs are obliged to account for it when choosing grid solutions

• E.g.: choose between paying for reinforcement or flex products


Question 2

• Which EU distribution automation trends does your project/concept fit into and how? • Very Active Distribution Networks


Question 3

• Which information would the DSO need, to observe the impacts of intermittent distributed energy resources (DG, DR, storage)? • Some of these info have been investigated in the

Questionnaire. • DSO: needs the following information:

• MV: • Type and purpose of connection,

• Info when your load profile will change heavily, even if you are not violating contractual boundaries.

• Technical configuration to ensure security of operation and customers personnel.

• LV: requirements are not this strict.

• Info level depends on voltage level of connection (planning phase)


Question 4

• What is the expected requirement to supply reliability (power quality and supply reliability) and how that might be reached? • DSO: The EN 50160 standard needs to be always

respected. • Control algorthms of INCREASE are proposing also to take into

account the operational security of the grid.

• INCREASE sets limits of MAS strategies to this norm,

• +- 10% trying to integrate more DRES without breaching V boundaries.

• Does the DSO security-prompted curtailment of DRES energy result in any market liability? • In TSO, TN, vis major.


Question 5

• What kinds of technologies and functionalities DSOs will need to utilize for occasional congestion management? • INCREASE technology

• 3 phase inverters

• Overlaying Control: traffic light prevents PQ violations in near real time.

• Local control: event driven. DSO does not interfere with it

• Overloading network assets can be allowed in a certain level with a short time duration. • INCREASE tried a solution to resolve the congestion by

curtailing equally power injection among PV inverters.

• Only the congestion with reverse power flow due to surplus PV injection considered at the moment.


Question 6

• What flexibilities, services and technological solutions are available to the DSO to host increasing RES and DERs? • Technology:

• Multi-Agent Structure; smart single and 3-phase Inverters

• Flexibilities: • MAS-controlled agents providing FEP

• Scheduling Control layer of INCREASE, we use flexibility from Demand Response to accommodate more RES.

• Optimal DR schedules allow to avoid curtailment of DRES injection.

• Ancillary Services: • 4 key ones, but looking for new ones


Question 7

• According to your active network concept what for, when (which year) and where DSO will purchase flexibility services? • Procuring FEP to mitigate network issues involves

uncertainty, as forecasting is uncertain.

• As the penetration of RES keeps increasing DSOs will operate their network closer to the limits. We expect for DSO to need the flexibility within 5 years.

• DSO: Will the DSO ever pay for flexibility? • If you have to pay for flex for 50y, maybe grid reinforcement is

cheaper on long term. DSO has to search for social optimum

• Reason: alleviate congestion in various time frames, and to make money (commercial)

• Stakeholders purchase services from INCREASE: • TSO: active power reserve: Balancing market.

• DSO: VC, VUM, CM: tendering.


Question 8

• How the coordination of flexibility resources between DSO, TSO, retailer, balance responsible party, etc. should be realized? • INCREASE envisions this done through an SC agent;

• DSO will act as the ultimate traffic light.

• Some of the roles are available for commercial actors (aggregator).

• The coordination should be done in a market fashion.

• DSO: may slowly assume more responsibilities on DN – namely DG istalled in DN • DSO: DN asset building and maintenance

• DN system operation: congestion mitigation, voltage control


Scheduling Control (SC) Overview

44


Question 9

• What kind of standardization is needed for information exchange needs in active networks? • DSO: Information exchange needs to cover timestamps,

timings and other contractual arrangements etc.

• All the solutions need to account for EU-wide standards (e.g. EN 50160)

• INCREASE WP4 field test cases take this into account


Question 10

• How should the regulation framework be changed for realizing your concept of active network? • INCREASE intends to analyze and is due on a report in

1 year.

• DSO: Green energy curtailment should become possible, not something undesirable. • Flexibility should become default, fixed amount and flex free

band, seen as an option.

• TSO: Active network operation should be performed in a cost minimizing way (e.g. market approach), making sure the grid constraints are not violated


Any questions?

Thank you for your attention!

INCREASE Project Presentation · •Questionnaire to gather the insight on challenges and solutions...

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