Design of Efficient Distributed Energy Resources (DER) Controller and Protection System

Abstract

This chapter presents the design of efficient controllers and protection systems for distributed energy resources (DERs)-based microgrids. The control strategies for DERs include decentralized, centralized, and hierarchical controllers. These controllers have been designed based on a robust extended linear quadratic Gaussian (LQG) control, which combines the Kalman estimator with the linear quadratic regulator with prescribed degree of stability (LQRPDS). Finally, this chapter demonstrates the validation of the design procedure of the DER controllers using eigenvalue analysis, offline time-domain simulations, and RTDS-based simulations. Moreover, various protection systems for DERs-based microgrids have been discussed briefly.

Appendix

IIDER Units Ratings: $\text {IIDER}_1$ − (10 + j6) kVA; $\text {IIDER}_2$ − (15 + j9) kVA; $\text {IIDER}_3$ 0− (20 + j12) kVA; $\text {IIDER}_4$ − (25 + j15) kVA. Static Active and Reactive Power Droop Gains: m $_{\text {P}1}$ = 6.28e − 4 rad/s/W, m $_{\text {P}2}$ = 4.18e − 4 rad/s/W, m $_{\text {P}3}$ = 3.14e − 4 rad/s/W, m $_{P4}$ = 2.52e − 4, n $_{\text {Q}1}$ = 1.66e − 3 V/VAR, n $_{\text {Q}2}$ = 1.11e − 3 V/VAR, n $_{\text {Q}3}$ = 8.33e − 4 V/VAR and n $_{\text {Q}4}$ = 6.66e − 4 V/VAR. IIDER unit Parameters: L $_{f}$ = 1.35 mH, C $_{\text {f}}$ = 50 $\upmu {}$F, R $_{\text {f}}$ = 0.1 $\Omega {}$, f $_{\text {sw}}$ = 8 kHz, w $_{c}$=31.41 rad/s, K $_{\text {pv}}$ = 0.05, K $_{\text {iv}}$ = 390, K $_{\text {pi}}$ = 10.5, K $_{\text {ii}}$ = 16e3, F = 0.75, f $_{\text {nl}}$ = 50.5 Hz, R $_{\text {c}}$ = 0.03 $\Omega {}$, L $_{\text {c}}$ = 0.35 mH. RIAL Parameters: L $_{\text {f}}$ = 2.3 mH, C $_{\text {f}}$ = 8.8 $\upmu {}$F, R $_{\text {f}}$ = 0.1 $\Omega {}$, f $_{\text {sw}}$ = 10 kHz, w $_{\text {c}}$ = 31.41 rad/s, K $_{\text {pv}}$ = 0.5, K $_{\text {iv}}$ = 150, K $_{\text {pi}}$ = 7, K $_{\text {ii}}$ = 25e3, R $_{\text {c}}$ = 0.03 $\Omega {}$, L $_{\text {c}}$ = 0.93 mH. Line Parameters: Line 1: (0.23 + j0.11) $\Omega {}$, Line 2: (0.35 + j0.58) $\Omega {}$, Line 3: (0.30 + j0.47) $\Omega {}$. Load Parameters: Induction Motor Load: 10 HP, 400 V, 50 Hz, $r_{\text {s}}\,=\,0.7834 \, \Omega$, $L_{\text {ss}}\,=\,127.1\,\text {mH}$, $r_{\text {r}}\,=\,7402 \, \Omega$, $L_{\text {rr}} = 127.1 \, \text {mH}$, $L_{\text {m}}= 124.1 \, \text {mH}$, P = 4, $T_{\text {L}}\,=\,47.75$ Nm; $\text {CPL}$: 12 kVA, r $_{\text {CPL}}$ = 13.224 $\Omega {}$/phase and cos $\alpha {}$ = 0.85; $\text {RIAL}$: 12 kW and R$_{\text {RIAL}}$ = 40.833 $\Omega {}$; R Load: 25 kW, R$R_{\text {Load}}$ = 6.347 $\Omega {}$/phase and $V_{\text {DC}}=700 \, \text {V}$.