# Research on Power Demand Suppression Based on Charging Optimization and BESS Configuration for Fast-Charging Stations in Beijing

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## Abstract

**:**

## Featured Application

**The proposed strategy is aimed to solve the peak charging power demand issue of pure electric bus fast-charging station. It is effective for the charging power suppression of stations in the area with extremely limited distribution capacity.**

## Abstract

## 1. Introduction

- (1)
- Using the charging price incentive mechanism to guide the charging behaviors of EV, owners can reduce the electricity cost, and the charging power is reduced during the peak duration of the distribution network.
- (2)
- Control the charging power through valley-filling to reduce the impact on the basic distribution load, and the total charging load level is less than hundreds of kilowatts.
- (3)
- Reduce the charging load fluctuation by configuring the energy storage system, considering the size of the ESS and the profit by using time-of-use tariffs, and the cycle lifetime of BESS is rarely considered.

## 2. Operation of the Fast-Charging Station

#### 2.1. Fast-Charging Station Configuration

#### 2.2. Station Operation

#### 2.3. Characteristics of the PEB Fleet

## 3. Operation Optimization

#### 3.1. The Proposed New Charging Topology

#### 3.2. Charging Schedule Optimization

## 4. Configuration of BESS

#### 4.1. Configuration Method

#### 4.2. Model Constraints and Optimization Steps

#### 4.3. Optimization Steps

## 5. Case Study and Results

#### 5.1. Charging Schedule Optimization

#### 5.2. BESS Configuration Case

#### 5.3. Results and Analysis

## 6. Conclusions

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 7.**Charging load and discharging power of BESS. (

**a**) The output power of BESS with the original charging load decreased to 912 kW; (

**b**) the output power of BESS with the original charging load decreased to 684 kW, and (

**c**) the output power of BESS with the optimized charging load decreased to 684 kW.

Parameter | Value |
---|---|

Vehicle Brand | Foton |

Vehicle Type | BJ612EVCA-19 |

Total Weight (kg) | 18,000.00 |

Shape (L × W × H) (mm) | 12,000 × 2550 × 3100 |

Battery Voltage (V) | 553.80 |

Battery Capacity (Ah) | 216.00 |

Electric Quantity (kWh) | 119.62 |

Line No. | Num. | Distance (km) | Time (minutes) | Loops before Charging |
---|---|---|---|---|

H55 | 5 | 9 | 30 | 3 or 4 |

H56 | 5 | 12 | 30 | 3 or 4 |

863 | 14 | 54 | 120 | 2 |

864 | 7 | 18 | 35 | 2 |

869 | 14 | 44 | 120 | 2 |

Line No. | Electricity (kWh) | Days of Month (d) | Distance Per Day (km) | Energy Cost (kWh/km) |
---|---|---|---|---|

H55 | 13,815.6 | 31 | 522 | 0.854 |

H56 | 15,985.6 | 31 | 600 | 0.859 |

863 | 51,936.8 | 31 | 1890 | 0.886 |

864 | 27,579.2 | 31 | 928 | 0.959 |

869 | 48,184.6 | 31 | 1628 | 0.955 |

Total/Ave. | 157,501.8 | 31 | 5568 | 0.912 |

Symbol | Explanation |
---|---|

${V}_{i,s}^{k}$ | Charging start time of PEB $k$ on the $i\mathrm{th}$ returning to the station |

${V}_{i,e}^{k}$ | Charging end time of PEB $k$ on the $i\mathrm{th}$ returning to the station |

${\mathrm{N}}_{B}^{k}$ | Number of PEB $k$ returning to the station without the last trip |

${d}_{i}^{k}$ | Charging or not of PEB $k$ (1 or 0) |

${t}_{i}^{k}$ | Charging duration related to ${d}_{i}^{k}$ |

${E}_{i}^{k}$ | Charging energy of PEB $k$ on $i\mathrm{th}$ returning to the station |

${E}_{0}^{k}$ | Full energy state of PEB $k$ |

${p}_{ch}$ | Nominal charging power of the stick |

${\mathrm{N}}_{stick}$ | Quantity of sticks of the station |

${\mathrm{C}}_{E\_\mathrm{total}}$ | Total cost of electricity (CNY) |

${c}_{ele}$ | Time-of-use tariffs |

$\Delta t$ | Time interval |

Symbol | Explanation |
---|---|

$x\%$ | Ratio of operation and maintenance cost of the batteries |

$y\%$ | Ratio of operation and maintenance cost of the converters |

${C}_{\mathrm{E}}$ | Cost of the BESS’s unit battery energy |

${C}_{\mathrm{P}}$ | Costs of the BESS’s unit converter power |

$E$ | Rated capacity of BESS |

$P$ | Rated power of BESS |

$\gamma $ | Discount rate |

${P}_{BESS,t}$ | Total charging power of BESS on time $t$ |

${N}_{sum}$ | Total number of charge–discharge cycle of BESS |

$SO{E}_{\mathrm{min}}$ | Minimum state of energy (SOE) of BESS |

$SO{E}_{\mathrm{max}}$ | Maximum SOE of BESS |

${p}_{\mathrm{ch},t}$ | Charging power of BESS on time $t$ |

${p}_{\mathrm{dis},t}$ | Discharging power of BESS on time $t$ |

$-{P}_{\mathrm{max}}$ | Maximum discharging power of BESS |

${P}_{\mathrm{max}}$ | Maximum charging power of BESS |

$n$ | Number of sample of BESS configuration simulation |

${T}_{n}$ | Sampling period of BESS configuration simulation |

$Q(n)$ | Energy of BESS at each time of the sample |

Line No. | Goal Loops | Length (km) | Suitable Loops | Distance (km) | Total ele. Cost (kWh) | SOC Cost (%) |
---|---|---|---|---|---|---|

H55 | 9(10) | 9 | 10 | 90 | 76.86 | 64.25 |

H56 | 10 | 12 | 7 | 84 | 72.16 | 60.32 |

863 | 5 | 27 | 3 | 81 | 71.77 | 60.00 |

864 | 4(5) | 36 | 2 | 72 | 69.05 | 57.72 |

869 | 5(6) | 22 | 3 | 66 | 63.03 | 52.69 |

Line No./Bus Label | A ^{1} | B | C | D | E | F | G |
---|---|---|---|---|---|---|---|

H55 | 7 | 7 | 7 | 7 | 7 | - | - |

H56 | 6 | 6 | 6 | 6 | 6 | - | - |

863 Up | 1, 3 ^{2} | 1, 3 | 1, 3 | 1, 3 | 2, 3 | 1, 3 | 1, 3 |

863 Down | 1, 3 | 2, 3 | 2, 3 | 2, 3 | 1, 3 | 1, 3 | 1, 3 |

864 | 1, 2 | 1, 2 | 1, 2 | 2, 3 | 2, 3 | 1, 2 | 1, 2 |

869 Up | 1, 2 | 1, 2 | 2, 4 | 1, 2 | 1, 2 | 3, 4 | 1, 2 |

869 Down | 1, 2 | 1, 2 | 3, 4 | 1, 2 | 1, 2 | 3, 4 | 1, 2 |

^{1}The label of PEB in each line, e.g., H55-A, H55-B …, H56-E.

^{2}The PEB 863 Up-A should charge on the first and third returns to the station.

Daytime Elec. (kWh) | Night Elec. (kWh) | Electricity Price | Peak Power (kW) | Elec. Fee (CNY/day) |
---|---|---|---|---|

5128.8 | 0 | TOU | 1601.7 | 4163.0 |

2344.6 | 2784.2 | TOU | 912.0 | 2618.3 |

Period | Time | Price (CNY/kWh) |
---|---|---|

Village | 23:00–7:00 | 0.3946 |

Flat | 7:00–10:00; 15:00–18:00 21:00–23:00 | 0.6950 |

Peak | 10:00–15:00; 18:00–21:00 | 1.0044 |

Parameter | Value |
---|---|

Basic capacity cost of the transformer (CNY/(kVA·month)) | 32 |

Battery cost (CNY/kWh) | 1500 |

Converter cost (CNY/kW) | 500 |

BESS lifetime (Year) | 8 |

Discount rate (%) | 3 |

SOC range of the BESS (%) | 20–90 |

Efficiency of charge–discharge of the BESS (%) | 95 |

Parameter | Original Load | Configure 1 | Configure 2 | Optimized Load | Configure 3 |
---|---|---|---|---|---|

Daytime energy (kWh) | 5128.8 | 5128.8 | 5128.8 | 2344.6 | 2344.6 |

Night energy (kWh) | 0 | 0 | 0 | 2784.2 | 2784.2 |

peak power (kW) | 1601.7 | 912.0 | 684.0 | 912.0 | 684.0 |

BESS battery (kWh) | 0 | 1292.9 | 1369.5 | 0 | 114.0 |

Battery cost (CNY/day) | 0 | 757.0 | 801.8 | 0 | 66.8 |

Converter cost (CNY/day) | 0 | 134.6 | 179.1 | 0 | 44.5 |

Dischar. Power (kW) | 0 | 689.8 | 917.8 | 0 | 228.0 |

Electricity fee (CNY) | 4163.0 | 3212.2 | 3155.9 | 2618.3 | 2560.3 |

Basic Capacity save (CNY/day) | 0 | 736.0 | 979.2 | 736.0 | 979.2 |

Cost without BCP save (CNY/day) | 4163.0 | 4036.6 | 4252.8 | 2618.3 | 2832.8 |

Cost with BCP save (CNY/day) | 4163.0 | 3367.8 | 3157.6 | 1882.3 | 1692.4 |

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**MDPI and ACS Style**

Yan, Y.; Jiang, J.; Zhang, W.; Huang, M.; Chen, Q.; Wang, H.
Research on Power Demand Suppression Based on Charging Optimization and BESS Configuration for Fast-Charging Stations in Beijing. *Appl. Sci.* **2018**, *8*, 1212.
https://doi.org/10.3390/app8081212

**AMA Style**

Yan Y, Jiang J, Zhang W, Huang M, Chen Q, Wang H.
Research on Power Demand Suppression Based on Charging Optimization and BESS Configuration for Fast-Charging Stations in Beijing. *Applied Sciences*. 2018; 8(8):1212.
https://doi.org/10.3390/app8081212

**Chicago/Turabian Style**

Yan, Yian, Jiuchun Jiang, Weige Zhang, Mei Huang, Qiang Chen, and Huang Wang.
2018. "Research on Power Demand Suppression Based on Charging Optimization and BESS Configuration for Fast-Charging Stations in Beijing" *Applied Sciences* 8, no. 8: 1212.
https://doi.org/10.3390/app8081212