This paper presents a novel contribution of a low complexity control scheme for voltage control of a dynamic voltage restorer (DVR). The scheme proposed utilizes an error-driven proportional-integral-derivative (PID) controller to guarantee better power quality performance in terms of voltage enhancement and stabilization of the buses, energy efficient utilization, and harmonic distortion reduction in a distribution network. This method maintains the load voltage close to or equal to the nominal value in terms of various voltage disturbances such as balanced and unbalanced sag/swell, voltage imbalance, notching, different fault conditions as well as power system harmonic distortion. A grasshopper optimization algorithm (GOA) is used to tune the gain values of the PID controller. In order to validate the effectiveness of the proposed DVR controller, first, a fractional order PID controller was presented and compared with the proposed one. Further, a comparative performance evaluation of four optimization techniques, namely Cuckoo search (CSA), GOA, Flower pollination (FBA), and Grey wolf optimizer (GWO), is presented to compare between the PID and FOPID performance in terms of fault conditions in order to achieve a global minimum error and fast dynamic response of the proposed controller. Second, a comparative analysis of simulation results obtained using the proposed controller and those obtained using an active disturbance rejection controller (ADRC) is presented, and it was found that the performance of the optimal PID is better than the performance of the conventional ADRC. Finally, the effectiveness of the presented DVR with the controller proposed has been assessed by time-domain simulations in the MATLAB/Simulink platform.

1. An Improved Approach for Robust Control of Dynamic
Voltage Restorer and Power Quality Enhancement Using
Grasshopper Optimization Algorithm
By
Eng. Ahmed Ibrahim Omar1
drahmedomar89@gmail.com
Supervisors
Prof. Dr. Essam M. Aboul-Zahab2 , Assoc. Prof. Dr. Shady H. E. Abdel Aleem2
Affiliations:
[1] Electrical Power and Machines Department, Higher Institute of Engineering, El-Shorouk City
[2] Electrical Power and Machines Department, Faculty of Engineering, Cairo University
[3] 15th of May Higher Institute of Engineering, Mathematical and Physical Sciences, Cairo
Paper Title

2. • Different control strategies for DVRs have been presented in many studies.
Also, using DVR, there are many research works offered on various power quality issues. Table 1
summarizes the recent works on DVR applications in terms of controller type and number,
optimization technique used, studied power quality issues, and findings.
• One can see from the literature that
 All controllers have many circuits such as: sags/swells detector circuit, positive/negative
sequence analyzer circuits for current and voltage controllers.
 As a result of that each controller circuit has PI controller, which takes a long time to
minimize the errors and enhance the voltage drifts.
 Also, many of these works did not consider finding optimal controller gains using
evolutionary metaheuristic techniques although of their impact on the dynamic response of
the controller.
 As well, effectiveness of DVR with a fractional order PID or active disturbance rejection
controller is not investigated in these works.
 In addition, the results are not sufficient to address most of the common power quality issues.
1 • Literature

3. 2 • System Configuration

4. The proposed DVR, as shown, comprises the following components:
 Energy storage (ES) unit.
 Universal bridge unit.
 Boosting transformer unit.
 Harmonic filter.
 Error-driven PID controller.
3 • The Proposed Compensator

5. 4 • The proposed control scheme of the DVR

6. 5 • Formulation of the optimization problem

7. 6 • Results and Discussions
Case I: Balanced voltage sag
Case II: Unbalanced voltage sag
Case III: Balanced voltage swell
Case IV: Unbalanced voltage swell
Case V: Three phase short circuit
Case VI: Double line to ground fault
Case VII: Single line to ground fault
Case VIII: Voltage imbalance
Case IX: Voltage notching
Case X: Transient

8. Case I: Balanced voltage sag Case VIII: Voltage imbalance

9. 7 • Contribution
Proposed Controller: PID with
Grasshopper Optimization Algorithm
Comparative analysis of optimal
PID with FOPID controller
Comparative analysis of optimal
PID with an active Disturbance
rejection controller (ADRC)
Four optimization techniques are presented to
compare between the PID and FOPID
performance in terms of fault conditions

10. 7 • Contribution
Proposed Controller: PID with
Grasshopper Optimization Algorithm
Comparative analysis of optimal
PID with FOPID controller
PID Controller has 3 control
parameters (Kp, Ki, Kd)
FOPID Controller has 5 control
parameters (Kp, Ki, Kd, λ, µ)

11. 7 • Contribution
Proposed Controller: PID with
Grasshopper Optimization Algorithm
Four optimization techniques are presented to
compare between the PID and FOPID
performance in terms of fault conditions
Cuckoo Search Algorithm (CSA) Flower Pollination Algorithm (FPA)
Grey Wolf Optimizer (GWO)
Grasshopper Optimization Algorithm
(GOA) - Proposed

12. • Comparative analysis of optimal PID with FOPID controller
• &
• Four optimization techniques are presented to compare between the
PID and FOPID performance in terms of fault conditions

13. 7 • Contribution
Proposed Controller: PID with
Grasshopper Optimization Algorithm
Comparative analysis of optimal
PID with an active Disturbance
rejection controller (ADRC)
Convert PID Controller into
State-Space Model

14. • Comparative analysis of optimal PID with an active
Disturbance rejection controller (ADRC)
Performance of DVR with ADRC and
optimal PID controllers during balanced sag
Performance of DVR with ADRC and
optimal PID controllers during balanced swell

15. 8 • Conclusion & Recommendations
 The paper presents a novel contribution of low-cost voltage control by using
a DVR scheme to cope with power quality issues of hybrid industrial loads
connected with a distribution network.
 The DVR scheme controlled by an optimal PID regulation controller is
employed to identify the optimum fitness value for minimization of the total
error-driven loop.
 A fractional order PID is presented and compared with a conventional PID to
verify the proposed method.
 Further, four optimization strategies, CSA, FBA, GOA, and GWO techniques,
was implemented between the PID and FOPID in terms of fault conditions.
 The results obtained revealed the superior effectiveness and robustness of
the optimal PID compared with the FOPID controller.
 Also, a comparative analysis of the results obtained using the proposed
controller and those obtained using ADRC is presented.
 The performance of the optimal PID is better than the performance of the
conventional ADRC.

16. 8 • Contacts
 For any help, don’t hesitate to contact me:
drahmedomar89@gmail.com
 For paper Link below:
 ISA Transactions Journal
https://www.sciencedirect.com/science/article/abs/pii/S0019057819302101