# Comparison of Local Volt/var Control Strategies for PV Hosting Capacity Enhancement of Low Voltage Feeders

## Abstract

**:**

## 1. Introduction

## 2. Model Description

#### 2.1. Low Voltage Test-Feeders

#### 2.1.1. Theoretical LV Test-Feeders

#### 2.1.2. Real LV Test-Feeder

#### 2.2. Prosumer Model

#### 2.3. Control Strategies

#### 2.3.1. cosφ(P)-Control

#### 2.3.2. Q(U)-Control

#### 2.3.3. L(U)-Control

#### 2.3.4. L(U)-Control Combined with Q-Autarkic Prosumers

## 3. Methodology

#### 3.1. Scenario Definition

#### 3.1.1. Load and Production

#### 3.1.2. DTR Primary Voltage

#### 3.1.3. Control Strategy

#### 3.1.4. Test-Feeders

#### 3.1.5. Scenario Overview

#### 3.2. Control Parameterization

#### 3.2.1. cosφ(P)-Control

_{min}) at peak active power production is varied between 0.9 under-excited and 1.

#### 3.2.2. Q(U)-Control

#### 3.2.3. L(U)-Control

#### 3.2.4. L(U)-Control Combined with Q-Autarkic Prosumers

#### 3.3. Result Evaluation

## 4. Hosting Capacity Enhancement by Local Reactive Power Control Strategies

#### 4.1. Theoretical LV Test-Feeders

#### 4.1.1. Long Overhead Line Test-Feeder

#### 4.1.2. Short Overhead Line Test-Feeder

#### 4.1.3. Long Cable Test-Feeder

#### 4.1.4. Short Cable Test-Feeder

#### 4.2. Real LV Test-Feeder

#### 4.3. Overview

#### 4.3.1. Current- and Voltage-Related Hosting Capacity Limits

#### 4.3.2. Grid Losses

## 5. Conclusions

## Funding

## Acknowledgments

## Conflicts of Interest

## Appendix A

Line Type | Branch Type | Profile [mm^{2}] | R′ [Ohm/km] | X′ [Ohm/km] | C′ [nF/km] | ${\mathit{I}}_{\mathit{t}\mathit{h}}^{\mathit{l}\mathit{i}\mathit{n}\mathit{e}}\left[\mathbf{A}\right]$ |
---|---|---|---|---|---|---|

Overhead line | Main branch | 95 | 0.3264 | 0.3557 | 0.0000 | 320 |

Overhead line | Sub branch | 50 | 0.6152 | 0.3764 | 0.0000 | 210 |

Cable | Main branch | 150 | 0.2060 | 0.0800 | 1040.0 | 275 |

Cable | Sub branch | 50 | 0.6410 | 0.0850 | 720.00 | 145 |

## Appendix B

Test-Feeder | cosφ(P) cosφ _{min} | Q(U) u _{c}[%] | L(U) u _{set-point}[%] | L(U) & Q_{aut}u _{set-point} [%] | |
---|---|---|---|---|---|

theoretical | Long OL | 0.905 | 103.20 | 106.70 | 106.40 |

Short OL | 0.932 | 106.30 | 109.18 | 108.97 | |

Long C | 0.900 | 103.00 | 108.70 | 108.60 | |

Short C | 0.920 | 103.30 | 109.88 | 109.88 | |

real | Branched C | 0.939 | 106.40 | 109.15 | 108.97 |

## Appendix C

**Figure A1.**Reactive power consumption of the inductive device in case of L(U) and its combination with Q-Autarkic prosumers for minimal and maximal DTR primary voltage and different test-feeders: (

**a**,

**b**) Long OL; (

**c**,

**d**) Short OL; (

**e**,

**f**) Long C; (

**g**,

**h**) Short C; (

**i**,

**j**) Branched C.

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**Figure 1.**Theoretical LV test-feeders: (

**a**) long overhead line feeder (“Long OL”); (

**b**) short overhead line (“Short OL”); (

**c**) long cable (“Long C”); (

**d**) short cable (“Short C”).

**Figure 4.**Load- and control-related reactive power flows provoked by the different control strategies: (

**a**) cosφ(P); (

**b**) Q(U); (

**c**) L(U); (

**d**) L(U) combined with Q-Autarkic prosumers.

**Figure 5.**Fundamental characteristics of different local control strategies for PV-inverters proposed by the Austrian grid code: (

**a**) cosφ(P); (

**b**) Q(U).

**Figure 6.**Methodology to parameterize different local control strategies for PV-inverters: (

**a**) cosφ(P)-control; (

**b**) Q(U)-control.

**Figure 7.**Current- and voltage-related hosting capacity limits of the long overhead line test-feeder for different control strategies: (

**a**,

**b**) no-control; (

**c**,

**d**) cosφ(P)-control; (

**e**,

**f**) Q(U)-control; (

**g**,

**h**) L(U)-control; (

**i**,

**j**) L(U)-control and Q-Autarkic prosumers.

**Figure 8.**Grid losses of the long overhead line test-feeder for the minimal and maximal DTR primary voltages and different control strategies: (

**a**) no-control; (

**b**) cosφ(P)-control; (

**c**) Q(U)-control; (

**d**) L(U)-control; (

**e**) L(U)-control and Q-Autarkic prosumers.

**Figure 9.**Current- and voltage-related hosting capacity limits of the short overhead line test-feeder for different control strategies: (

**a**,

**b**) no-control; (

**c**,

**d**) cosφ(P)-control; (

**e**,

**f**) Q(U)-control; (

**g**,

**h**) L(U)-control; (

**i**,

**j**) L(U)-control and Q-Autarkic prosumers.

**Figure 10.**Grid losses of the short overhead line test-feeder for the minimal and maximal DTR primary voltages and different control strategies: (

**a**) no-control; (

**b**) cosφ(P)-control; (

**c**) Q(U)-control; (

**d**) L(U)-control; (

**e**) L(U)-control and Q-Autarkic prosumers.

**Figure 11.**Current- and voltage-related hosting capacity limits of the long cable test-feeder for different control strategies: (

**a**,

**b**) no-control; (

**c**,

**d**) cosφ(P)-control; (

**e**,

**f**) Q(U)-control; (

**g**,

**h**) L(U)-control; (

**i**,

**j**) L(U)-control and Q-Autarkic prosumers.

**Figure 12.**Grid losses of the long cable test-feeder for the minimal and maximal DTR primary voltages and different control strategies: (

**a**) no-control; (

**b**) cosφ(P)-control; (

**c**) Q(U)-control; (

**d**) L(U)-control; (

**e**) L(U)-control and Q-Autarkic prosumers.

**Figure 13.**Current- and voltage-related hosting capacity limits of the short cable test-feeder for different control strategies: (

**a**,

**b**) no-control; (

**c**,

**d**) cosφ(P)-control; (

**e**,

**f**) Q(U)-control; (

**g**,

**h**) L(U)-control; (

**i**,

**j**) L(U)-control and Q-Autarkic prosumers.

**Figure 14.**Grid losses of the short cable test-feeder for the minimal and maximal DTR primary voltages and different control strategies: (

**a**) no-control; (

**b**) cosφ(P)-control; (

**c**) Q(U)-control; (

**d**) L(U)-control; (

**e**) L(U)-control and Q-Autarkic prosumers.

**Figure 15.**Current- and voltage-related hosting capacity limits of the branched cable test-feeder for different control strategies: (

**a**,

**b**) no-control; (

**c**,

**d**) cosφ(P)-control; (

**e**,

**f**) Q(U)-control; (

**g**,

**h**) L(U)-control; (

**i**,

**j**) L(U)-control and Q-Autarkic prosumers.

**Figure 16.**Grid losses of the branched cable test-feeder for the minimal and maximal DTR primary voltages and different control strategies: (

**a**) no-control; (

**b**) cosφ(P)-control; (

**c**) Q(U)-control; (

**d**) L(U)-control; (

**e**) L(U)-control and Q-Autarkic prosumers.

**Figure 17.**Voltage and current profiles of the branched cable test-feeder for a PV-penetration of 7.5 kW/prosumer, the minimal and maximal DTR primary voltages, and different control strategies: (

**a**,

**b**) no-control; (

**c**,

**d**) cosφ(P)-control; (

**e**,

**f**) Q(U)-control; (

**g**,

**h**) L(U)-control; (

**i**,

**j**) L(U)-control and Q-Autarkic prosumers.

**Figure 19.**Additional grid losses provoked by different control strategies for minimal and maximal DTR primary voltages, different LV test-feeders and different PV-penetrations: (

**a**) 5 kW/prosumer; (

**b**) 10 kW/prosumer.

DTR Primary Voltage | |
---|---|

0.96 p.u | 1.06 p.u. |

${P}_{init}^{load},\text{}{P}_{r}^{PV}$ = 0.00 kW | ${P}_{init}^{load},\text{}{P}_{r}^{PV}$ = 0.00 kW |

${P}_{init}^{load},\text{}{P}_{r}^{PV}$ = 0.01 kW | ${P}_{init}^{load},\text{}{P}_{r}^{PV}$ = 0.01 kW |

… | … |

${P}_{init}^{load},\text{}{P}_{r}^{PV}$ = 17.49 kW | ${P}_{init}^{load},\text{}{P}_{r}^{PV}$ = 17.49 kW |

${P}_{init}^{load},\text{}{P}_{r}^{PV}$ = 17.50 kW | ${P}_{init}^{load},\text{}{P}_{r}^{PV}$ = 17.50 kW |

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## Share and Cite

**MDPI and ACS Style**

Schultis, D.-L.
Comparison of Local Volt/var Control Strategies for PV Hosting Capacity Enhancement of Low Voltage Feeders. *Energies* **2019**, *12*, 1560.
https://doi.org/10.3390/en12081560

**AMA Style**

Schultis D-L.
Comparison of Local Volt/var Control Strategies for PV Hosting Capacity Enhancement of Low Voltage Feeders. *Energies*. 2019; 12(8):1560.
https://doi.org/10.3390/en12081560

**Chicago/Turabian Style**

Schultis, Daniel-Leon.
2019. "Comparison of Local Volt/var Control Strategies for PV Hosting Capacity Enhancement of Low Voltage Feeders" *Energies* 12, no. 8: 1560.
https://doi.org/10.3390/en12081560