# A Hybrid Reactive Power Control Method of Distributed Generation to Mitigate Voltage Rise in Low-Voltage Grid

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## Abstract

**:**

## 1. Introduction

## 2. Voltage Sensitivity Analysis

## 3. Q(V) and PF(P) Control Methods

#### 3.1. Power Factor Control Methods Based on Active Power

#### 3.2. Voltage Dependent Reactive Power Q(V) Control Method

#### 3.3. Characteristics of Existing Reactive Power Control Methods

## 4. Proposed Reactive Power Control Method

#### Performence Analysis of the Proposed Method

## 5. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 6.**(

**a**) Reactive power output; and (

**b**) node voltage of distributed generators with different methods when the output of each DG is set as shown in Figure 5 and all loads are set to 0 p.u.

**Figure 7.**(

**a**) Reactive power output; and (

**b**) node voltage of distributed generators with different method when the output of each DG is set as shown in Figure 5 and set all loads to 0.3 p.u. of rated active power of DG.

**Figure 8.**Weight factor $K$ as a function of active power $P$ and Block diagram for proposed method; (

**a**) weight factor $K$ as a function of active power $P$; (

**b**) Block diagram.

**Figure 10.**Setting of reactive power control methods applied to test feeder model; (

**a**) PF-P characteristic curve for PF(P) method; (

**b**) Q-V characteristic curve for Q(V); (

**c**) K-P characteristic curve for proposed method.

**Figure 11.**Measured power generation profiles in 1-h averages during; (

**a**) January 2017 and (

**b**) July 2017; and (

**c**) histogram of hours of measured power generation at Yeongam-gun, Jeollanam-do, Republic of Korea for 2017.

**Figure 12.**Active power output and reactive power output by the different methods at (

**a**) DG1 and (

**b**) DG8 and reactive power output by reactive power control method.

**Figure 13.**Reactive power absorption amounts for each DG by the reactive power control methods when the active power output is (

**a**) 0.6 p.u.; (

**b**) 0.9 p.u.; and (

**c**) 1.0 p.u.

**Figure 15.**Comparison of max voltage at critical bus and grid losses according to reactive power control method.

Symbol | Values | Remarks |
---|---|---|

${S}_{base}$ | 10 (kVA) | Base power |

${V}_{base}$ | 0.38 (kV) | Base voltage |

${V}_{Limit}$ | $0.38\pm 0.038$ (kV) | Voltage limit (${V}_{base}\pm 10\%$) |

${P}_{DG,i}$ | 10 (kW) | Nominal active power of distributed generators |

${Z}_{OHL,i}$ | 0.0038 + j0.0027 (p.u) | Overhead line(OHL) impedance, i = 1~7 |

${Z}_{Grid}$ | 0.0001 + j0.0001 (p.u) | Medium voltage grid impedance |

${Z}_{TR}$ | 0.0009 + j0.0020 (p.u) | Transformer impedance |

${V}_{Slack}$ | 1.02 (p.u) | Slack bus voltage |

Method | Parameters | Unit | Values |
---|---|---|---|

fixed PF | PF reference | - | 0.95 |

PF(P) | xlookup of PF(P) | p.u | [0.00, 0.40, 1.00, 1.20] |

ylookup of PF(P) | - | [1.00, 1.00, 0.95, 0.95] | |

Q(V) | xlookup of Q(V) | p.u | [0.80, 0.90, 0.95, 1.05, 1.10, 1.20] |

ylookup of Q(V) | p.u | [0.33, 0.33, 0.00, 0.00, −0.33, −0.33] |

Reactive Power Control Strategy | Max. Voltage at Critical Bus [p.u] | Network Power Losses | Maximum Transformer Loading [%] | Reactive Power Consumption [MVArh/year] | |
---|---|---|---|---|---|

Active Power [MWh/year] | Reactive Power [MVArh/year] | ||||

No Q | 1.1140 | 3.7724 | 3.2924 | 75.14 | 0.00 |

fixed PF | 1.0876 | 4.2897 | 3.7410 | 80.45 | −38.35 |

PF(P) | 1.0878 | 3.9910 | 3.4816 | 80.41 | −16.58 |

Q(V) | 1.0965 | 3.8974 | 3.3919 | 76.58 | −9.18 |

Proposed | 1.0903 | 3.9019 | 3.3960 | 79.25 | −9.44 |

**Table 4.**Maximum voltage reduction at critical bus and system losses increase rate of reactive power control.

Reactive Power Control Strategy | Max. Voltage Reduction at Critical Bus (Equation (10)) | Increasing Rate of System Losses [%] (Equation (11)) | $\frac{{\mathit{R}}_{\mathit{\u2206}\mathit{V}\mathit{m}\mathit{a}\mathit{x}\left(\mathit{Q}\mathit{c}\mathit{o}\mathit{n}\mathit{t}.\right)}}{{\mathit{R}}_{\mathit{P}\mathit{l}\mathit{o}\mathit{s}\mathit{s}\left(\mathit{Q}\mathit{c}\mathit{o}\mathit{n}\mathit{t}.\right)}}$ |
---|---|---|---|

fixed PF | 0.2640 | 13.71 | 0.0193 |

PF(P) | 0.2620 | 5.79 | 0.0453 |

Q(V) | 0.1750 | 3.31 | 0.0529 |

Proposed | 0.2370 | 3.43 | 0.0691 |

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## Share and Cite

**MDPI and ACS Style**

Kim, S.-B.; Song, S.-H.
A Hybrid Reactive Power Control Method of Distributed Generation to Mitigate Voltage Rise in Low-Voltage Grid. *Energies* **2020**, *13*, 2078.
https://doi.org/10.3390/en13082078

**AMA Style**

Kim S-B, Song S-H.
A Hybrid Reactive Power Control Method of Distributed Generation to Mitigate Voltage Rise in Low-Voltage Grid. *Energies*. 2020; 13(8):2078.
https://doi.org/10.3390/en13082078

**Chicago/Turabian Style**

Kim, Soo-Bin, and Seung-Ho Song.
2020. "A Hybrid Reactive Power Control Method of Distributed Generation to Mitigate Voltage Rise in Low-Voltage Grid" *Energies* 13, no. 8: 2078.
https://doi.org/10.3390/en13082078