centralized reactive power management

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Outcome of a Study conducted for the Bayernwerk AG

Innovative Reactive Power Management for Distribution Grids with High PV Penetration

Contact:

Thomas Stetz, [email protected] Kraiczy, [email protected] Wang, [email protected]

Results presented at the VDE ETG Conference „From Smart Grids to Smart Markets“, Kassel, Germany, 2015

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Outline

Scope of the Study

High PV Penetration in Distribution Grids: Bayernwerk‘s Smart Grid Region „Seebach“

Seebach‘s Reactive Power Characteristic today

Expected future Reactive Power Characteristic

Central Reactive Power Management utilizing controllable MV PV-Systems

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Scope of the Study

Background: PV at LV level shall contribute to static voltage support by means of reactive power provision!

Part 1 (Autonomous Reactive Power Provision): How would a bulk reactive power provision affect the reactive power

characteristic of a distribution grid?

What kind of autonomous reactive power provision method would be most suitable for LV application?

Part 2 (Centralized Reactive Power Management): Can controllable PV systems at MV level contribute to control the reactive

power exchange between MV (20 kV) and HV (110 kV) level?

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Bayernwerk‘s Smart Grid Region „Seebach“

Smart Grid „Seebach“:• 15 PV-Systems at MV-Level (10.7 MW)• 1.450 PV-Systems at LV-Level (~30 MW)• Winter peak-load ~ 12.5 MVA

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Pow

er [M

W, M

var]

Q @

HV

/MV

Sub

stat

ion

P @ HV/MV Substation

Power Flows at the „Seebach“ 110/20kV Substation

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IMPACT OF AUTONOMOUS REACTIVEPOWER PROVISION BY PV AT LV-LEVEL

Part 1

results by Markus Kraiczy, Fraunhofer IWES

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Expected Q-Flows at 110/20 kV Substation

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Expected Q-Gradients at 110/20 kV Substation

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Summary

Bulk reactive power provision by LV PV systems can have a significant affect on the reactive power characteristic of the „Seebach“ grid

The fixed power factor method has the highest impact on the reactive power exchange with the upstream 110 kV grid

The CosPhi(P) method will lead to the highest reactive power gradients within the „Seebach“ grid

The Q(U) method shows the lowest impact on the reactive power exchange AND reactive power gradients

Q(U) method turns out to be the favorable option for static voltage support at LV level

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CENTRAL REACTIVE POWER MANAGEMENT

Part 2

results by Haonan Wang, Markus Kraiczy (Konrad Diwold), Fraunhofer IWES

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Technical Framework for Implementing Q-Management into Bayernwerk‘s Monitoring and Control Architecture

Goal: Establish a source of controllable reactive power for Bayernwerk AG

Consideration of MV PV-systems only

Reliable and stable operation

Low effort for integrating Q-management into existing monitoring and control architecture

Harmonization with local Q(U)-control

Avoid PV technology upgrades, if possible

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Control Concept for Central Q-Management

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Algorithm and Characteristics ΔQ(ΔQ)-Characteristic of central Q-Management

Extended Q(V)-Characteristic

Cen

tral

Q-M

anag

emen

t

3. Determine the Q-Setpoint deviation for controllable MV-DGs according to the

ΔQDG(ΔQHV)-Characteristic

5. MV-DG-Controller calculates the Q-Setpoint and limits it within the operation area according

to the extended Q(U)-Characteristic

6. Set the reactive power of MV-DG

1. Determine the target value of reactive power exchange at HV/MV-NCP (QHV_set)

4. Send Q-Setpoint deviation to the controller of MV-DGs

Optimized network state

2. Determine the current setpoint deviation of Q-Exchange at HV/MV-NCP (ΔQHV)

Loca

lQ-C

ontr

ol

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Summary

The proposed central Q-Management approach…

can be easily implemented into Bayernwerk‘s monitoring and control architecture only one external measurement value required

does not require any extensive controller parameterization only one central characteristic for all PV systems

harmonizes with the local Q(V) control no additional measurements for voltage control required

stable even under n-1 conditions

is a relevant source of controllable reactive power for Bayernwerk problem of intermittency can be overcome with Q@night functionality

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Work in Progress…

Cost-benefit assessments and comparison with conventional reactive power sources

Real-time controller-in-the-loop tests

Implementation and field tests within the Bayernwerk service area

Your contacts for further information:

Thomas Stetz, [email protected]

Markus Kraiczy, [email protected]

Haonan Wang, [email protected]

centralized reactive power management

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