Planning and design of regional integrated energy station considering load growth mode

Abstract

The existing integrated energy station (IES) planning does not consider the lifecycle of the energy conversion equipment and the growth modes of various loads at the same time, which will inevitably affect the economics of the IES planning. This paper proposes a planning and design of regional IESs that takes the load growth mode into account, aiming at the lowest total cost of regional IESs in the planning lifecycle. Based on the operation mode about of the IES coupled with the three-networks involving the natural gas network (NGN), power distribution network (PDN) and transportation network (TN), the selection and capacity configuration of the equipment in the IES are optimized. The solution process of staged planning for IESs is proposed based on load calculation, power distribution and economic checking computations. The optimization calculation is carried out by reasonably dividing the time interval and setting the calculation criteria for the power distribution module. Finally, four MW-level IESs coupled with IEEE 33-node PDN, 20-node NGN and 12-node TN are simulated on the basis of MATLAB. The results show that the equipment investment and operation costs of the regional IESs can be decreased by about 7.1%, and the accumulated waste of various equipment capacity is decreased by nearly 16.51 MW, which verifies the effectiveness of the proposed model and strategy. Furthermore, the results show that it is more practical and economical to consider the equipment lifecycle and load growth mode for the medium and long-term planning of IESs.

Appendices

Appendix A

Simulation data

See Tables 6, 7, 8, 9 and Figs. 12, 13.

Table 6 The data of O–D traffic demand

Table 7 The data of optional equipment

Table 8 The operation data of IES

Table 9 The operation cost of IES

Fig. 12

Load curves under three typical day scenarios

Fig. 13

DG curves under three typical day scenarios

Appendix B

Equations

• (1) TN constraints are as follows:

  $$x_{a,\omega } = \sum\limits_{{rs \in \Lambda^{{{\text{OD}}}} }} {\sum\limits_{{k \in K_{rs}^{{{\text{CV}}}} }} {f_{rs,k,\omega }^{{{\text{CV}}}} \delta_{rs,k,a}^{{{\text{CV}}}} } } + \sum\limits_{{rs \in \Lambda^{{{\text{OD}}}} }} {\sum\limits_{{k \in K_{rs}^{{\text{N - CV}}} }} {f_{rs,k,\omega }^{{\text{N - CV}}} \delta_{rs,k,a}^{{\text{N - CV}}} } } ,\forall a \in \Theta^{{{\text{TL}}}} ,\forall \omega$$

  (B1)
  $$\sum\limits_{{k \in K_{rs}^{{{\text{CV}}}} }} {f_{rs,k,\omega }^{{{\text{CV}}}} } { = }m_{rs,\omega }^{{{\text{CV}}}} ,\forall rs \in \Lambda^{{{\text{OD}}}} ,\forall \omega$$

  (B2)
  $$\sum\limits_{{k \in K_{rs}^{{\text{N - CV}}} }} {f_{rs,k,\omega }^{{\text{N - CV}}} } { = }m_{rs,\omega }^{{\text{N - CV}}} ,\forall rs \in \Lambda^{{{\text{OD}}}} ,\forall \omega$$

  (B3)
  $$f_{rs,k,\omega }^{{{\text{CV}}}} \ge 0,\forall rs \in \Lambda^{{{\text{OD}}}} ,\forall k \in K_{rs}^{{{\text{CV}}}} ,\forall \omega$$

  (B4)
  $$f_{rs,k,\omega }^{{\text{N - CV}}} \ge 0,\forall rs \in \Lambda^{{{\text{OD}}}} ,\forall k \in K_{rs}^{{\text{N - CV}}} ,\forall \omega$$

  (B5)
  $$c_{rs,k,\omega }^{{{\text{CV}}}} = \sum\limits_{{a \in \Theta^{TL} }} {t_{a,\omega } \cdot\delta_{rs,k,a}^{{{\text{CV}}}} } ,\forall k \in K_{rs}^{{{\text{CV}}}} ,\forall \omega$$

  (B6)
  $$c_{rs,k,\omega }^{{N - {\text{CV}}}} = \sum\limits_{{a \in \Theta^{TL} }} {t_{a,\omega } \cdot\delta_{rs,k,a}^{{N - {\text{CV}}}} } ,\forall k \in K_{rs}^{{N - {\text{CV}}}} ,\forall \omega$$

  (B7)
  $$t_{a,\omega } (x_{a,\omega } ) = \left\{ \begin{gathered} t_{a,\omega }^{0} [1 + J_{{\text{R}}} .(\frac{{x_{a,\omega } }}{{\overline{C}_{a}^{{{\text{TL}}}} }})^{4} ],\forall a \in \Theta^{{\text{TL - R}}} \hfill \\ t_{a,\omega }^{0} (1 + J_{{\text{C}}} .\frac{{x_{a,\omega } }}{{\overline{C}_{a}^{{{\text{TL}}}} - x_{a,\omega } }}),\forall a \in \Theta^{{\text{TL - C}}} \hfill \\ \end{gathered} \right.,\forall \omega$$

  (B8)

In (B1)–(B8), $\Lambda^{{{\text{OD}}}}$ is the set of O–D pairs of traffic demand; $K_{rs}^{{{\text{CV}}}} /K_{rs}^{{\text{N - CV}}}$ is the set of feasible paths from the starting point r to the ending point s; $f_{rs,k,\omega }^{{{\text{CV}}}} /f_{rs,k,\omega }^{{\text{N - CV}}}$ is the flow of O–D to path k under r-s in the $\omega$ period; $\delta_{rs,k,a}^{{{\text{CV}}}} /\delta_{rs,k,a}^{{\text{N - CV}}}$ is the correlation coefficient between the section and the path; $m_{rs,\omega }^{{{\text{CV}}}} /m_{rs,\omega }^{{\text{N - CV}}}$ is the traffic demand of O–D under r-s in the $\omega$ period; $c_{rs,k,\omega }^{{{\text{CV}}}} /c_{rs,k,\omega }^{{\text{N - CV}}}$ is the time cost of route travel of O–D to path k under r-s in the $\omega$ period; $t_{a,\omega }^{0}$ is the average passing time when the road section has zero flow; $\overline{C}_{a}^{{{\text{TL}}}}$ is the maximum traffic capacity of the section; $J_{{\text{R}}}$, $J_{{\text{C}}}$ are the shape parameters of the time function.

• (B) NGN constraints are as follows:

The natural gas network is mainly composed of gas wells, pipelines, pressurizers, and loads. The following constraints should be considered in natural gas network modeling

• (1) Gas well supply constraints

  $$\underline{G}_{j,\omega }^{{\text{W}}} \le g_{j,\omega }^{{\text{W}}} \le \overline{G}_{j,\omega }^{{\text{W}}} ,\forall j \in \Theta^{{{\text{GW}}}} ,\forall \omega$$

  (B9)

In (B9), $\underline{G}_{j,\omega }^{{\text{W}}} ,\overline{G}_{j,\omega }^{{\text{W}}}$ are, respectively, the lower and upper limits of the natural gas quantity that can be supplied by the gas well j during the time period $\omega$.

• (B) Pressure constraint

  $$\hat{\pi }_{1,\omega } = C,\forall \omega$$

  (B10)
  $$\underline{\Pi }_{j} \le \hat{\pi }_{j,\omega } \le \overline{\Pi }_{j} ,\forall j \in \Theta^{{{\text{GN}}}} ,\forall \omega$$

  (B11)

In (B10)–(B11), $C$ is a constant; $\hat{\pi }_{j,\omega }$ is the square of the gas pressure of the natural gas node j during the time period $\omega$; $\underline{\Pi }_{j}$ and $\overline{\Pi }_{j}$ are, respectively, the square of their lower and upper limits; $\Theta^{{{\text{GN}}}}$ represents a collection of natural gas nodes.

• (C) Constraints on maximum pipeline flow

  $$\underline{G}_{ij,\omega } \le g_{ij,\omega } \le \overline{G}_{ij,\omega } ,\forall ij \in \Theta^{{{\text{GP}}}} ,\forall \omega$$

  (B12)

In (B12), $g_{ij,\omega }$ is the flow rate of natural gas pipeline ij; $\underline{G}_{ij,\omega }$ and $\overline{G}_{ij,\omega }$ are the lower and upper limit, respectively; $\Theta^{{{\text{GP}}}}$ represents a collection of natural gas pipelines.

• (D) Natural gas pipeline flow model

  $${\text{sgn}} (\hat{\pi }_{i,\omega } - \hat{\pi }_{j,\omega } )g_{ij,\omega }^{2} = \psi_{ij} (\hat{\pi }_{i,\omega } - \hat{\pi }_{j,\omega } ),\forall ij \in \Theta^{{{\text{GP}}}} ,\forall \omega$$

  (B13)

The above equation is Weymouth steady-state power flow equation, which is used to describe the relationship between the gas flow in the natural gas pipeline and the pressure of the nodes at both ends. Where: ${\text{sgn}} (x)$ represents the symbolic function about $x$; $\psi_{ij}$ is the airflow transmission parameter of the pipeline ij.

• (E) Constraints on node traffic balance

  $$\sum\limits_{{jk \in \Omega^{{\text{G - JK}}} (j)}} {g_{jk,\omega } } = \sum\limits_{{ij \in \Omega^{{\text{G - IJ}}} (j)}} {g_{ij,\omega } + g_{j,\omega }^{{\text{W}}} } - g_{j,\omega }^{{\text{L}}} ,\forall j \in \Theta^{{{\text{GN}}}} ,\forall \omega$$

  (B14)

The above formula ensures the flow balance of natural gas nodes. Where, $\Omega^{{\text{G - JK}}} (j)$ and $\Omega^{{\text{G - IJ}}} (j)$, respectively, represent a collection of first and last nodes of natural gas pipelines j; $g_{j,\omega }^{{\text{L}}}$ is the natural gas load of natural gas node j in time period $\omega$.

• (F) Compression device constraints

  $$\hat{\pi }_{i,\omega } = \hat{\Phi }_{ij} \hat{\pi }_{j,\omega } ,\forall ij \in \Theta^{{{\text{GC}}}} ,\forall \omega$$

  (B15)
  $$\underline{G}_{ij,\omega }^{{\text{C}}} \le g_{ij,\omega }^{{\text{C}}} \le \overline{G}_{ij,\omega }^{{\text{C}}} ,\forall ij \in \Theta^{{{\text{GC}}}} ,\forall \omega$$

  (B16)

In (B15)–(B16), $\hat{\Phi }_{ij}$ is the square of the boost ratio of the natural gas node; $g_{ij,\omega }^{{\text{C}}}$ is the air flow through between i to j and in the pressurizer; $\underline{G}_{ij,\omega }^{{\text{C}}}$、$\overline{G}_{ij,\omega }^{{\text{C}}}$ are, respectively, their lower and upper limits; $\Theta^{{{\text{GC}}}}$ is a collection of compression device.

• (1) PDN constraints are as follows:

Distribution network constraints mainly include power flow constraints, safe operation constraints and load reduction constraints, which are, respectively, expressed as follows:

• (1) Power flow constraint

  $$\sum\limits_{{jk \in \Omega^{{\text{E - JK}}} (j)}} {p_{jk,\omega } } = \sum\limits_{{ij \in \Omega^{{\text{E - IJ}}} (j)}} {p_{ij,\omega } } - \sum\limits_{{ij \in \Omega^{{\text{E - IJ}}} (j)}} {\hat{I}_{ij,\omega } R_{ij} } + p_{j,\omega }^{{{\text{TS}}}} - p_{j,\omega }^{{\text{L}}} ,\forall j \in \Theta^{{{\text{EB}}}} ,\forall \omega$$

  (B17)
  $$\sum\limits_{{ij \in \Omega^{{\text{E - JK}}} (j)}} {q_{jk,\omega } } = \sum\limits_{{ij \in \Omega^{{\text{E - IJ}}} (j)}} {q_{ij,\omega } } - \sum\limits_{{ij \in \Omega^{{\text{E - IJ}}} (j)}} {\hat{I}_{ij,\omega } X_{ij} } + q_{j,\omega }^{{{\text{TS}}}} - q_{j,\omega }^{{\text{L}}} ,\forall j \in \Theta^{{{\text{EB}}}} ,\forall \omega$$

  (B18)
  $$\hat{U}_{j,\omega } = \hat{U}_{i,\omega } - 2(p_{ij,\omega } R_{ij} + q_{ij,\omega } X_{ij} ) + \hat{I}_{ij,\omega } (R_{ij}^{2} + X_{ij}^{2} ),\forall ij \in \Theta^{{{\text{EL}}}} ,\forall \omega$$

  (B19)
  $$\hat{U}_{i,\omega } \hat{I}_{ij,\omega } = p_{ij,\omega }^{2} + q_{ij,\omega }^{2} ,\forall ij \in \Theta^{{{\text{EL}}}} ,\forall \omega$$

  (B20)

In (B17)–(B20), $\Omega^{{\text{E - JK}}} (j)$ and $\Omega^{{\text{E - IJ}}} (j)$, respectively, represent the set of power grid feeders whose first and last nodes are j; $p_{ij,\omega }$ and $q_{ij,\omega }$, respectively, represent the active power and reactive power on the feeder ij; $X_{ij}$ is the reactance of the feeder; $\hat{U}_{j,\omega }$ is the square of the grid node j voltage.

• (B) Constraints on safe and stable operation

  $$\underline{U} \le \hat{U}_{j,\omega } \le \overline{U} ,\forall j \in \Theta^{{{\text{EB}}}} ,\forall \omega$$

  (B21)
  $$0 \le \hat{I}_{ij,\omega } \le \overline{I} ,\forall ij \in \Theta^{{{\text{EL}}}} ,\forall \omega$$

  (B22)
  $$\underline{P}_{j}^{{{\text{TS}}}} \le p_{j,\omega }^{{{\text{TS}}}} \le \overline{P}_{j}^{{{\text{TS}}}} ,\forall j \in \Theta^{{{\text{TS}}}} ,\forall \omega$$

  (B23)
  $$\underline{Q}_{j}^{{{\text{TS}}}} \le q_{j,\omega }^{{{\text{TS}}}} \le \overline{Q}_{j}^{{{\text{TS}}}} ,\forall j \in \Theta^{{{\text{TS}}}} ,\forall \omega$$

  (B24)

In (B21)–(B24), $\underline{U}$ and $\overline{U}$ are, respectively, the square of the lower and upper limits of the voltage amplitude of the grid node j; $\overline{I}$ is the square of the upper limit of current amplitude; $\underline{P}_{j}^{{{\text{TS}}}}$ and $\overline{P}_{j}^{{{\text{TS}}}}$, respectively, represent the lower and upper limits of the available active power of the substation j; $\underline{Q}_{j}^{{{\text{TS}}}}$ and $\overline{Q}_{j}^{{{\text{TS}}}}$ are, respectively, the lower and upper limits of the available reactive power of the substation j.