Roadside photovoltaic site selection method considering glare impact
A roadside photovoltaic site selection method considering glare impact includes: obtaining latitudes, longitudes, ground elevations, and contour vertex eights of photovoltaic modules above ground of a photovoltaic array; calculating a sun movement path, determining an installation manner based on predicted solar radiation on inclined surfaces of the photovoltaic array; calculating an elevation angle and an azimuth angle of each reflected light caused by the inclined surfaces; arranging observation points and conducting a glare impact analysis for each observation point; determining whether to adjust an installation tilt angle of each photovoltaic module or distances between adjacent photovoltaic modules; comparing solar radiation received on the inclined surfaces between the critical tilt angle and the optimal tilt angle; in response to a difference in the solar radiation less than a set value, accepting the critical tilt angle; and completing the glare impact analysis for each observation point, and providing recommended installation locations.
1 . A roadside photovoltaic site installation method considering a glare impact, comprising:
S1, obtaining latitudes, longitudes, ground elevations, and contour vertex heights of photovoltaic modules above ground at a proposed installation location of a photovoltaic array, and collecting nearby solar radiation observation data;
S2, calculating a sun movement path comprising a solar altitude angle and a solar azimuth angle, and determining an installation manner of the photovoltaic array at the proposed installation location based on predicted solar radiation on inclined surfaces of the photovoltaic array at the proposed installation location, wherein the installation manner comprises an optimal tilt angle and an optimal azimuth angle for a fixed arrangement;
S3, calculating an elevation angle and an azimuth angle of each of reflected lights caused by the inclined surfaces based on sun positions at different seasons and times and inclined surface angle information of the photovoltaic modules of the photovoltaic array;
S4, determining an affected road length range based on a spatial geometric relationship between the reflected lights and adjacent roads of the photovoltaic array, determining observation paths along a road centerline facing the reflected lights, arranging observation points at predetermined intervals, and conducting a glare impact analysis for each of the observation points;
S5, determining whether to adjust an installation tilt angle of each of the photovoltaic modules or distances between adjacent photovoltaic modules based on results of the glare impact analysis for each of the observation points, and finding a critical tilt angle of each of the photovoltaic modules, wherein the critical tilt angle of each of the photovoltaic modules does not produce glare hazards, wherein the results of the glare impact analysis comprise: static glare impact grading and duration, and whether a flicker effect occurs;
S6, comparing solar radiation received on an inclined surface of each of the photovoltaic modules at the critical tilt angle and the optimal tilt angle; in response to a difference in the solar radiation less than a set value, accepting the critical tilt angle as the installation tilt angle, and in response to the difference in the solar radiation greater than or equal to the set value, taking measures to eliminate the glare impact, or marking a corresponding installation location as unsuitable; and
S7, completing the glare impact analysis and an evaluation for all the observation points along each of the observation paths, and providing recommended installation locations, wherein the recommended installation locations do not produce the glare hazards, and installing the photovoltaic modules at the recommended installation locations;
wherein at the step S3:
a bracket tilt angle on a curved road section is equal to a monthly optimal tilt angle β opt of each of the photovoltaic modules, an azimuth angle Φ of each of the photovoltaic modules is equal to a bracket azimuth angle and consistent with an azimuth angle of a slope surface or the road centerline of the curved road section, the solar altitude angle is denoted as α, the solar azimuth angle is denoted as θ, the installation tilt angle of each of the photovoltaic modules is denoted as β, and an azimuth angle of each of the photovoltaic modules is denoted as Φ, and a direction unit vector of each of the reflected lights is {right arrow over (q)}=[q x , q y , q z ] T , calculated according to an equation (15):
{right arrow over (q)}=M T ×{right arrow over (b)} (15);
M T represents a transpose matrix of a matrix M, and expressions for the matrix M and a vector {right arrow over (b)} are as follows:
M
=
[
0
-
n
z
n
y
n
z
0
-
n
x
-
n
y
n
x
0
n
x
n
y
z
]
;
b
→
=
[
-
n
z
k
y
+
n
y
k
z
n
z
k
x
-
n
x
k
z
-
n
y
k
x
+
n
x
k
y
-
(
n
x
k
x
+
n
y
k
y
+
n
z
k
z
)
]
;
{right arrow over (n)}=[n x , n y , n z ] represents an outward normal unit vector of the inclined surface of each of the photovoltaic modules, {right arrow over (k)}=[k x , k y , k z ] represents a direction unit vector of an incident light, and component expressions of {right arrow over (n)} and {right arrow over (k)} are as follows:
n x =sin β sin Φ;
n y =sin β cos Φ;
n z =cos β;
k x =cos(−α)cos(270°−θ);
k y =cos(−α)sin(270°−θ);
k z =sin(−α);
after obtaining the direction unit vector of each of the reflected lights {right arrow over (q)}=[q x , q y , q z ] T , the elevation angle η and the azimuth angle ψ of each of the reflected lights are obtained by converting the direction unit vector of each of the reflected lights from a Cartesian vector to horizontal coordinates, as follows:
η=arcsin( q z ) (16);
ψ
=
arctan
(
q
x
q
y
)
;
(
17
)
an impact range of the reflected lights is determined after calculating directions of the reflected lights.
2 . The roadside photovoltaic site installation method according to claim 1 , wherein the observation paths comprise a road or a building group in a roadside service area, wherein the photovoltaic array is allowed for being observed in a travel direction on the road.
3 . The roadside photovoltaic site installation method according to claim 1 , wherein the observation points are set along a road travel direction, with a view height of 1.2 meters (m) or 2.4 m; when the photovoltaic array is allowed for being observed on a point within a view field of a driver, the point is marked as an observation point and numbered, and when the photovoltaic array is not visible on the point within the view field of the driver due to an obstruction by obstacles, there is no need to set the observation point.
4 . The roadside photovoltaic site installation method according to claim 1 , wherein in response to the fixed arrangement as the installation manner of the photovoltaic array, the optimal tilt angle and the optimal azimuth angle are calculated based on monthly average irradiance, direct component irradiance and diffuse component irradiance, and the optimal tilt angle and the optimal azimuth angle comprise: an annual optimal tilt angle and an annual optimal azimuth angle, a quarterly optimal tilt angle and a quarterly optimal azimuth angle, and the monthly optimal tilt angle and a monthly optimal azimuth angle;
in response to a grid-connected photovoltaic power generation system, the optimal tilt angle maximizes annual radiation on the inclined surfaces of the photovoltaic array, and in response to a stand-alone photovoltaic power generation system, the optimal tilt angle ensures a radiation on the inclined surfaces of the photovoltaic array during a month with lowest irradiance; and
the elevation angle and the azimuth angle of each of the reflected lights at different months and times are calculated based on the optimal tilt angle and the optimal azimuth angle.