# Improved Faulted Phase Selection Algorithm for Distance Protection under High Penetration of Renewable Energies

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## Abstract

**:**

## 1. Introduction

## 2. Analysis of Commercial Protection Devices before a 100% Renewable Generation Scenario

- Line 5–7 tests allow to analyze the behavior of distance protection before Type 4 WT current injection. Protection under study is located at Bus 7 side of the line and measured fault current is supplied only by the Type 4 WT.
- Line 4–5 tests allow to analyze the behavior of distance protection before PV generator current injection. During these tests, line 1–5 and Type 4 WT are disconnected, and the current contribution measured by protection located at bus 5 only will come from PV generator.

- ○
- Four commercial protections have been tested
- ○
- Different fault locations, with faults applied within zone 1 and zone 2 of distance protection.
- ○
- Different installed power in Type-4 WT: 40 MW and 200 MW.
- ○
- Different types of fault: Single line to ground (SLG), line to line (LL), line to line to ground (LLG) and three phase faults (LLL).
- ○
- In distance protection tests, solid faults were applied to avoid well-known classical problems associated to overreach/underreach operation of this function with resistive faults.
- ○

#### 2.1. Percentage of Missed Trips

#### 2.2. Results from Protection Relay Oscillography

- PRE-FAULT STATE: Shows the standard symmetrical current injection in normal operation, before the fault.
- + AND − SEQ: Before WTs control systems respond to the fault state and regulate current injection, the behavior of the Type 4 WT is similar to SGs response, injecting both positive and negative sequence currents. The duration of this initial period depends on the response time of the WTs control systems.
- TRANSITION: During this stage, WTs control reduce progressively negative sequence contribution once they react after the detection of the fault condition.
- ONLY + SEQ: Once the WTs control systems eliminate negative sequence current, a symmetrical current injection can be observed even in an asymmetrical fault.

## 3. Comparison of Type 4 WT and SG Current Contribution Based on Superimposed Quantities Theory

#### 3.1. Classical Superimposed Quantities Theory Used in Protection Relays

#### 3.2. Comparison of Type 4 WT and SG Current Contribution Based on Superimposed Quantities Theory

## 4. Proposed Algorithm

#### 4.1. Proposed Algorithm Structure

#### 4.2. Criterion 1. Positive vs. Negative Sequence Currents

_{criterion1}that represent the difference between positive and negative sequence phasor (phase A) and compares it with the angular sectors observed in Figure 11a,b to obtain the faulted phase selection. Figure 11a shows sectors corresponding to SLG and LLG events involving any combination of phases and Figure 11b for LL faults. This protection principle is based on the theory of sequence networks and has been traditionally used by protection relay manufacturers [31].

- -
- Reference zones are defined for each fault type: AG faults reference zone goes from 330° to 30°, ABG sector from 30° to 90°, BG sector from 90° to 150°, BCG sector from 150° to 210° CG sector from 210° to 270° and CAG sector from 270° to 330°.
- -
- In every sector, a dead band can be defined in order to delimit the zone between the adjacent zones and to avoid wrong zone activations. These dead bands can be set to zero.
- -
- The final operation zone is the area obtained by subtracting the dead band to the reference operation zone and is the area used to apply criterion 1. If dead band is set to zero degrees, the final and the reference operation zones coincide.

#### 4.3. Criterion 2. Negative vs. Zero Sequence Currents

_{criterion2}is between 90° and 150°.

#### 4.4. Adaptive Window Applied to Criteria 1 and 2

_{criterion1}is between 210° and 270° and δ

_{criterion2}is between 90° and 150°. This can be appreciated in Figure 14.

#### 4.5. Criterion 3: Adaptation of the Superimposed Quantities Theory to Deal with Renewable Current Contribution

#### 4.6. Directionality

## 5. Results

- Two lines has been used to test the faults: Line 5–7 for Type 4 WT current contribution and line 4–5 for PV generator current contribution (see Figure 2).
- Faults has been simulated in four locations of each line under test: 0%, 50%, 70%, 90%, 100% forward of the line from bus 7 for type 4 WT and from bus 5 for PV generator. Additionally, for backward faults test in line 5–7 the fault is applied behind bus 5 (100% of the line from bus 7) with the protection located at bus 5.
- Two generation levels have been defined: 40 and 200 MW and 100% of this generation is provided by renewable generators.Nine types of faults have been tested: AG, BG, CG, AB, BC, CA, ABG, BCG, CAG.
- Three fault resistance has been defined: 0, 1 and 10 ohm.

## 6. Conclusions

## 7. Patents

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 3.**Distribution of missed trips between different types of faults for the four different vendors (percentage of missed trips over the total number of faults) for 100% renewables scenario for type 4-WT.

**Figure 4.**Distribution of missed trips between different types of faults for the four different vendors (percentage of missed trips over the total number of faults) for 100% renewables scenario for PV generator.

**Figure 6.**Instantaneous values of scalar products based on superimposed quantities theory for AG fault when current contribution comes from SG (

**a**) or Type 4 WT (

**b**).

**Figure 7.**Instantaneous values of scalar products based on superimposed quantities theory for AB fault when current contribution comes from SG (

**a**) or Type 4 WT (

**b**).

**Figure 8.**Instantaneous values of scalar products based on superimposed quantities theory for ABG fault when current contribution comes from SG (

**a**) or Type 4 WT (

**b**).

**Figure 11.**Criterion 1 for single line to ground and line to line to ground faults (

**a**) and line to line faults (

**b**).

**Figure 12.**Criterion 2 for single line to ground and line to line to ground faults Operation principle based on sequence networks [17].

**Table 1.**Classical classification of different types of fault according to the values of scalar products for a synchronous grid [29].

Fault Type | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{A}\mathbf{B}}$ | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{B}\mathbf{C}}$ | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{C}\mathbf{A}}$ |
---|---|---|---|

$\mathrm{AG}$ | $\Delta {\mathrm{T}}_{\mathrm{AB}}$ | $0$ | $\Delta {\mathrm{T}}_{\mathrm{AB}}$ |

$\mathrm{BG}$ | $\Delta {\mathrm{T}}_{\mathrm{AB}}$ | $\Delta {\mathrm{T}}_{\mathrm{AB}}$ | $0$ |

$\mathrm{CG}$ | $0$ | $\Delta {\mathrm{T}}_{\mathrm{BC}}$ | $\Delta {\mathrm{T}}_{\mathrm{BC}}$ |

$\mathrm{AB},\mathrm{ABG}$ | $\Delta {\mathrm{T}}_{\mathrm{AB}}$ | $0.25\xb7\Delta {\mathrm{T}}_{\mathrm{AB}}$ | $0.25\xb7\Delta {\mathrm{T}}_{\mathrm{AB}}$ |

$\mathrm{BC},\text{}\mathrm{BCG}$ | $0.25\xb7\Delta {\mathrm{T}}_{\mathrm{BC}}$ | $\Delta {\mathrm{T}}_{\mathrm{BC}}$ | $0.25\xb7\Delta {\mathrm{T}}_{\mathrm{BC}}$ |

$\mathrm{CA},\mathrm{CAG}$ | $0.25\xb7\Delta {\mathrm{T}}_{\mathrm{CA}}$ | $0.25\xb7\Delta {\mathrm{T}}_{\mathrm{CA}}$ | $\Delta {\mathrm{T}}_{\mathrm{CA}}$ |

ABC | $\Delta {\mathrm{T}}_{\mathrm{AB}}$ | $\Delta {\mathrm{T}}_{\mathrm{AB}}$ | $\Delta {\mathrm{T}}_{\mathrm{AB}}$ |

**Table 2.**Margin of action for AB and ABG faults [20].

Fault Type | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{A}\mathbf{B}}$ | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{B}\mathbf{C}}$ | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{C}\mathbf{A}}$ |
---|---|---|---|

$\mathrm{AB}$ | $\Delta {\mathrm{T}}_{\mathrm{AB}}$ | $>0.15\xb7\Delta {\mathrm{T}}_{\mathrm{AB}}$ $<0.35\xb7\Delta {\mathrm{T}}_{\mathrm{AB}}$ | $>0.15\xb7\Delta {\mathrm{T}}_{\mathrm{AB}}$ $<0.35\xb7\Delta {\mathrm{T}}_{\mathrm{AB}}$ |

**Table 3.**Summary of results obtained in the comparison done between synchronous generator and Type 4 WT with AG, AB and ABG fault using instantaneous scalar products.

Type of Fault | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{A}\mathbf{B}}$ | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{B}\mathbf{C}}$ | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{C}\mathbf{A}}$ | |||
---|---|---|---|---|---|---|

Sync. Generator | Type 4 WT | Sync. Generator | Type 4 WT | Sync. Generator | Type 4 WT | |

AG | $\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | $\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | ≈0 | <0 | $\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | <0.25·$\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ |

AB | $\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | $\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | $0.25\xb7\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | ≈$0.50\xb7\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | $0.25\xb7\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | <0 |

ABG | $\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | $\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | ≈$0.25\xb7\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | $0.50\xb7\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | ≈$0.25\xb7\Delta {\mathrm{T}}_{\mathrm{A}\mathrm{B}}$ | ≈0 |

Fault Type | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{A}\mathbf{B}}$ | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{B}\mathbf{C}}$ | $\mathbf{\Delta}{\mathbf{T}}_{\mathbf{C}\mathbf{A}}$ |
---|---|---|---|

$\mathrm{AG}$ | $\Delta {\mathrm{T}}_{\mathrm{AB}}$ | $<0.1\xb7\Delta {\mathrm{T}}_{\mathrm{AB}}$ | NC |

BG | NC | $\Delta {\mathrm{T}}_{\mathrm{BC}}$ | $<0.1\xb7\Delta {\mathrm{T}}_{\mathrm{BC}}$ |

$\mathrm{CG}$ | $<0.1\xb7\Delta {\mathrm{T}}_{\mathrm{CA}}$ | NC | $\Delta {\mathrm{T}}_{\mathrm{CA}}$ |

$\mathrm{AB},\mathrm{ABG}$ | $\Delta {\mathrm{T}}_{\mathrm{AB}}$ | $>0.25\xb7\Delta {\mathrm{T}}_{\mathrm{AB}}$ $<0.75\xb7\Delta {\mathrm{T}}_{\mathrm{AB}}$ | NC |

$\mathrm{BC},\text{}\mathrm{BCG}$ | NC | $\Delta {\mathrm{T}}_{\mathrm{BC}}$ | $>0.25\xb7\Delta {\mathrm{T}}_{\mathrm{BC}}$ $<0.75\xb7\Delta {\mathrm{T}}_{\mathrm{BC}}$ |

$\mathrm{CA},\mathrm{CAG}$ | $>0.25\xb7\Delta {\mathrm{T}}_{\mathrm{CA}}$ $<0.75\xb7\Delta {\mathrm{T}}_{\mathrm{CA}}$ | NC | $\Delta {\mathrm{T}}_{\mathrm{CA}}$ |

R = 0 ohm | R = 1 ohm | R = 10 ohm | Overall Results | ||||||
---|---|---|---|---|---|---|---|---|---|

Type of Fault | Correct Detection | Wrong Detection | Correct Detection | Wrong Detection | Correct Detection | Wrong Detection | Correct Detection | Wrong Detection | Correct (%) |

AG | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

BG | 30 | 0 | 30 | 0 | 29 | 1 | 89 | 1 | 99% |

CG | 28 | 2 | 29 | 1 | 30 | 0 | 87 | 3 | 97% |

ABG | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

BCG | 27 | 3 | 27 | 3 | 29 | 1 | 83 | 7 | 92% |

CAG | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

AB | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

BC | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

CA | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

TOTAL | 265 | 5 | 266 | 4 | 268 | 2 | 799 | 11 | 99% |

R = 0 ohm | R = 1 ohm | R = 10 ohm | Overall Results | ||||||
---|---|---|---|---|---|---|---|---|---|

Type of Fault | Correct Detection | Wrong Detection | Correct Detection | Wrong Detection | Correct Detection | Wrong Detection | Correct Detection | Wrong Detection | Correct (%) |

AG | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

BG | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

CG | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

ABG | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

BCG | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

CAG | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

AB | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

BC | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

CA | 30 | 0 | 30 | 0 | 30 | 0 | 90 | 0 | 100% |

TOTAL | 270 | 0 | 270 | 0 | 270 | 0 | 810 | 0 | 100% |

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## Share and Cite

**MDPI and ACS Style**

Martínez Carrasco, E.; Comech Moreno, M.P.; Villén Martínez, M.T.; Borroy Vicente, S.
Improved Faulted Phase Selection Algorithm for Distance Protection under High Penetration of Renewable Energies. *Energies* **2020**, *13*, 558.
https://doi.org/10.3390/en13030558

**AMA Style**

Martínez Carrasco E, Comech Moreno MP, Villén Martínez MT, Borroy Vicente S.
Improved Faulted Phase Selection Algorithm for Distance Protection under High Penetration of Renewable Energies. *Energies*. 2020; 13(3):558.
https://doi.org/10.3390/en13030558

**Chicago/Turabian Style**

Martínez Carrasco, Eduardo, María Paz Comech Moreno, María Teresa Villén Martínez, and Samuel Borroy Vicente.
2020. "Improved Faulted Phase Selection Algorithm for Distance Protection under High Penetration of Renewable Energies" *Energies* 13, no. 3: 558.
https://doi.org/10.3390/en13030558