US 12,755,076 B2 · Heat supply network hydraulic circuit modeling method for comprehensive energy system scheduling

Abstract

A heat supply network hydraulic circuit modeling method for a comprehensive energy system scheduling is provided. The hydraulic analysis model is unified with the power network model, and the connection between the hydraulic dynamic state and the hydraulic steady state is established. Based on the characteristic equations of thermal pipelines, flow control valves and compressors, this method abstracts hydraulic circuit element models such as hydraulic resistance, hydraulic inductance, and hydraulic pressure source, establishes hydraulic branch characteristics of the heat supply network based on the above hydraulic circuit elements, establishes the hydraulic topology constraints of the heat supply network based on Kirchhoff-like voltage and current laws, and establishes the steady hydraulic network equation by combining the above hydraulic branch characteristics and hydraulic topology constraints.

A control apparatus for a comprehensive energy system, the comprehensive energy system comprising a heat supply network, and the control apparatus comprising a processor and a memory storing computer-executable instructions thereon, wherein the computer-executable instructions, when executed by the processor, cause the control apparatus to perform:

step 1 of establishing a device model for a heat supply network, comprising:
step 1-1 of establishing a thermal pipeline model in the heat supply network, comprising:
step 1-1-1 of establishing a mass conservation equation and a momentum conservation equation describing a one-dimensional flow process of water in the thermal pipeline:
∂
ρ
∂
t
+
∂
ρ
⁢
v
∂
x
=
0
,
and
⁢
∂
ρ
⁢
v
∂
t
+
∂
ρ
⁢
v
2
∂
x
+
∂
p
∂
x
+
λ
⁢
ρ
⁢
v
2
2
⁢
D
+
ρ
⁢
g
⁢
sin
⁢
θ
=
0
,
where ρ, ν and p denote a density, a flow rate and a pressure of the water, respectively, λ, D and θ denote a friction coefficient, an inner diameter and an inclination angle of the thermal pipeline, respectively, g denotes an acceleration of gravity, and t and x denote time and space, respectively;
step 1-1-2 of establishing, based on a fact that the water is an incompressible fluid, a differential equation of the density of the water about the time and the space:
∂
ρ
∂
t
=
∂
ρ
∂
x
=
0
;
step 1-1-3 of ignoring the convection term
∂
ρ
⁢
v
2
∂
x
in the momentum conservation equation in the step 1-1-1, that is
∂
ρ
⁢
v
2
∂
x
≈
0
,
and performing an incremental linearization approximation on the square term of the flow rate in the resistance term
λ
⁢
ρ
⁢
v
2
2
⁢
D
,
that is, letting ν2≈2νbaseν−νbase2, where νbase denotes a base value of the flow rate of the water in the thermal pipeline, taking a flow rate in a design condition;
step 1-1-4 of substituting the steps 1-1-2 and 1-1-3 into the step 1-1-1 to get following equations:
∂
G
∂
x
=
0
,
and
⁢
1
A
⁢
∂
G
∂
t
+
∂
p
∂
x
+
λ
⁢
G
base
ρ
⁢
A
2
⁢
D
⁢
G
-
λ
⁢
G
base
2
2
⁢
ρ
⁢
A
2
⁢
D
+
ρ
⁢
g
⁢
sin
⁢
θ
=
0
,
where G denotes a mass flow of the water, G=ρνA denotes a cross-sectional area of the thermal pipeline, and Gbase denotes a base value of the mass flow corresponding to the base value of the flow rate, that is Gbase=ρνbaseA;
step 1-1-5 of establishing, based on the step 1-1-4, equations of a flow difference and a pressure drop at both ends of a micro-element dx of the thermal pipeline:
dG
=
0
,
and
⁢
dp
=
-
dx
A
·
dG
dt
-
λ
⁢
G
base
⁢
dx
ρ
⁢
A
2
⁢
D
⁢
G
-
(
ρ
⁢
g
⁢
sin
⁢
θ
-
λ
⁢
G
base
2
2
⁢
ρ
⁢
A
2
⁢
D
)
⁢
dx
,
where dG denotes the flow difference at both ends of the micro-element of the thermal pipeline, and dp denotes the pressure drop at both ends of the micro-element of the thermal pipeline;
step 1-1-6 of obtaining, based on the equations of the flow difference and the pressure drop at both ends of the micro-element of the thermal pipeline in the step 1-1-5, calculation equations of a hydraulic resistance Rh, a hydraulic inductance Lh and a hydraulic pressure source Eh in the thermal pipeline as follows:
R
h
=
λ
⁢
G
base
/
(
ρ
⁢
A
2
⁢
D
)
,
L
h
=
1
/
A
,
and
E
h
=
ρ
⁢
g
⁢
sin
⁢
θ
-
λ
⁢
G
base
2
/
(
2
⁢
ρ
⁢
A
2
⁢
D
)
,
wherein the micro-element dx of the thermal pipeline denotes a hydraulic circuit comprising 3 elements, and the entire thermal pipeline denotes a distributed parameter hydraulic circuit;
step 1-1-7 of establishing, based on element parameters of the distributed parameter hydraulic circuit of the thermal pipeline in the step 1-1-6, element parameters of a lumped parameter hydraulic circuit of the thermal pipeline:
R
=
R
h
⁢
l
,
L
=
L
h
⁢
l
,
and
E
=
E
h
⁢
l
,
where R denotes a hydraulic resistance in the lumped parameter hydraulic circuit of the thermal pipeline, L denotes a hydraulic inductance in the lumped parameter hydraulic circuit of the thermal pipeline, E denotes a hydraulic pressure source in the lumped parameter hydraulic circuit of the thermal pipeline, and l denotes a length of the thermal pipeline;
step 1-1-8 of performing Fourier transform on an excitation of the lumped parameter hydraulic circuit of the thermal pipeline, decomposing the excitation of the lumped parameter hydraulic circuit of the thermal pipeline into a plurality of sinusoidal steady state excitations at different frequencies, and establishing algebraic equations of a lumped parameter frequency domain hydraulic circuit corresponding to each frequency component ω in the sinusoidal steady state excitation:
p
l
=
p
0
-
(
R
+
j
⁢
ω
⁢
L
)
⁢
G
0
-
E
,
and
G
l
=
G
0
,
where p0 and G0 denote a pressure and a flow at a head end of the thermal pipeline, respectively, and p1, and G1, denote a pressure and a flow at a terminal end of the thermal pipeline;
step 1-2 of establishing a flow control valve model in the heat supply network, comprising:
step 1-2-1 of establishing an equation between a pressure difference p on both sides of the flow control valve and a mass flow G of the flow control valve:
p
=
k
v
⁢
G
2
,
where k, denotes an opening coefficient of the flow control valve, and G denotes the mass flow of the water;
step 1-2-2 of performing an incremental linearization approximation on the square term G2 of the mass flow in the step 1-2-1, that is G2=2GbaseG−Gbase2, and converting the equation between the pressure difference p on both sides of the flow control valve and the mass flow G of the flow control valve in the step 1-2-1 into the following equation:
p
=
2
⁢
k
v
⁢
G
base
·
G
-
k
v
⁢
G
base
2
,
step 1-2-3 of defining, based on the step 1-2-2, calculation equations of a hydraulic resistance Rν and a hydraulic pressure source Eν of the flow control valve as follows:
R
v
=
2
⁢
k
v
⁢
G
base
,
and
E
v
=
-
k
v
⁢
G
base
2
;
step 1-3 of establishing a compressor model in the heat supply network, comprising:
step 1-3-1 of establishing an equation between a pressure difference p on both sides of the compressor and a mass flow G of the water of the compressor at a given rotation speed:
p
=
-
(
k
p
⁢
1
⁢
G
2
+
k
p
⁢
2
⁢
ω
p
⁢
G
+
k
p
⁢
3
⁢
ω
p
2
)
,
where kp1, kp2 and kp3 denote inherent coefficients of the compressor, which are obtained from a factory nameplate of the compressor or obtained through an external characteristic testing and fitting, and ωp denotes a rotation frequency of the compressor;
step 1-3-2 of performing an incremental linearization approximation on the square term G2 of the mass flow in the step 1-3-1, that is G2=2GbaseG−Gbase2, and converting the step 1-3-1 into following equation:
p
=
-
(
2
⁢
k
p
⁢
1
⁢
G
base
+
k
p
⁢
2
⁢
ω
p
)
·
G
-
(
k
p
⁢
3
⁢
ω
p
2
-
k
p
⁢
1
⁢
G
base
2
)
;
step 1-3-3 of defining, based on the step 1-3-2, calculation equations of a hydraulic resistance Rp and a hydraulic pressure source Ep of the compressor as follows:
R
p
=
-
(
2
⁢
k
p
⁢
1
⁢
G
base
+
k
p
⁢
2
⁢
ω
p
)
,
and
E
p
=
k
p
⁢
1
⁢
G
base
2
-
k
p
⁢
3
⁢
ω
p
2
;
step 2 of establishing a hydraulic branch characteristic of the heat supply network, comprising:
step 2-1 of establishing, based on the models of the thermal pipeline, the flow control valve and the compressor established in the step 1, a hydraulic branch characteristic equation of the heat supply network:
G
b
=
y
b
(
p
b
-
E
b
)
,
where Gb denotes a base value of a mass flow corresponding to a base value of a flow rate in a hydraulic branch, pb denotes a hydraulic pressure difference at both ends of the hydraulic branch, yb denotes a branch admittance formed by a hydraulic resistance and a hydraulic inductance in the hydraulic branch, and Eb denotes a sum of hydraulic pressure sources in the hydraulic branch;
step 2-2 of writing hydraulic branch equations of all the hydraulic branches in the heat supply network into a matrix form as follows:
G
b
=
y
b
(
p
b
-
E
b
)
,
where Gb, pb and Eb denote a column vector composed of the mass flow of the water in all the hydraulic branches in the heat supply network, a column vector composed of the hydraulic pressure difference at both ends of each branch in all the hydraulic branches in the heat supply network, and a column vector composed of the hydraulic pressure sources in all the hydraulic branches in the heat supply network, respectively, and yb denotes a diagonal matrix composed of the admittances of all the branches of the heat supply network;
step 3 of establishing hydraulic topology constraints of the heat supply network, comprising:
step 3-1 of defining a node-branch correlation matrix Ah in the heat supply network, which is a matrix of n rows and m columns, where n denotes a number of nodes in the heat supply network, and m denotes a number of branches in the heat supply network, (Ah)i,j denotes an element in an ith row and a jth column in denotes that the branch j is not connected to the node i, (Ah)i,j=1 denotes that the branch j flows out from the node i , and (Ah)i,j=−1 denotes that the branch j flows into the node i;
step 3-2 of establishing, based on Kirchhoff-like current law, a mass conservation equation of nodes of the heat supply network:
AhGb=Gn,
where Gn denotes a column vector formed by water injection of each node, and when the heat supply network is a closed network, then Gn=0;
step 3-3 of establishing, based on Kirchhoff-like voltage law, a loop pressure drop equation of the heat supply network:
A
h
T
⁢
p
n
=
p
b
,
where pn denotes a column vector composed of a hydraulic pressure value of each node;
step 4 of establishing a dynamic hydraulic network equation of the heat supply network, comprising:
step 4-1 of substituting the hydraulic topology constraints established in the steps 3-2 and 3-3 into the branch characteristic equation established in the step 2-2 and obtaining an unreduced form of a hydraulic network equation of the heat supply network as follows:
A
h
⁢
y
b
⁢
A
h
T
⁢
p
n
=
G
n
+
A
h
⁢
y
b
⁢
E
b
;
step 4-2 of defining a generalized node admittance matrix Yh and a generalized node injection vector
G
n
′
as follows:
Y
h
=
A
h
⁢
y
b
⁢
A
h
T
,
and
G
n
′
=
G
n
+
A
h
⁢
y
b
⁢
E
b
;
step 4-3 of substituting the Yh and
G
n
′
defined in the step 4-2 into the unreduced form of the hydraulic network equation of the heat supply network in the step 4-1, and obtaining the hydraulic network equation in the heat supply network of following form:
Y
h
⁢
p
n
=
G
n
′
,
wherein the above hydraulic network equation describes a hydraulic dynamic of the heat supply network;
step 5 of deleting a hydraulic inductance element in the hydraulic circuit model of the heat supply network, recalculating, based on the step 4, the generalized node admittance matrix Yh, and only taking a zero-frequency component in a frequency domain to degenerate the dynamic hydraulic circuit model into a steady hydraulic circuit model, wherein the steady hydraulic circuit model is the heat supply network hydraulic circuit model for the comprehensive energy system control;
and
step 6 of controlling operation of the comprehensive energy system according to the heat supply network hydraulic circuit model,
wherein the heat supply network comprises a flow control valve and a compressor, and
wherein the controlling operation of the comprehensive energy system according to the heat supply network hydraulic circuit model, comprises:
adjusting an opening coefficient of the flow control valve and/or a rotation speed of the compressor, based on solution results of the heat supply network hydraulic circuit model.

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Heat supply network hydraulic circuit modeling method for comprehensive energy system scheduling

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Heat supply network hydraulic circuit modeling method for comprehensive energy system scheduling

Life of this patent

Abstract

Claims1