JPH11231012A - Method and apparatus for measuring ground state of solar cell module - Google Patents

Abstract

(57) [Problem] To provide a measuring method and a measuring device capable of measuring a ground state of a solar cell module with good workability. SOLUTION: An electrode is arranged on a solar cell module in which a metal part to be grounded is connected to a ground electrode so as to form a capacitance between the metal part and an AC voltage between the electrode and the ground electrode. Is applied, and the flowing current is detected to measure the grounding state of the metal part. According to this, it is not necessary to measure the grounding resistance value each time one solar cell module is laid as in the related art, and the grounding state is measured from the surface of the solar cell module after all the solar cell modules are laid. And the workability is greatly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a ground state of a solar cell module in a photovoltaic power generation system.

[0002]

2. Description of the Related Art In recent years, there has been great expectation for a solar power generation system, which is a clean energy source, due to an increase in awareness of environmental and energy problems that have spread on a global scale. Ground installation type installed on the field,
There is a roof installation type and the like installed on the roof of a house. However, since a large installation area is required to install a solar cell, a roof installation type that makes effective use of the roof of the house is mainly used. There are also two types of roof-installed types, mainly a gantry-installed type and a roof material-integrated type.The roof material has a function as a roof material by stacking solar cells on a roof steel plate and modularizing it. The number of integrated solar cell modules is increasing.

When building a solar power generation system,
The solar cell array is configured by determining the number of series-parallel solar cell modules so that a desired output can be obtained by grasping the characteristics of the solar cell module.

[0004] Generally, the above-mentioned solar cell module includes:
It is desirable to connect the outer metal part (steel plate for roof) of all solar cell modules to the grounding pole, especially in a non-insulated connection with the power supply system, in order to prevent electric shocks due to accidents, breakdowns, etc. When using a transformerless inverter, the need for grounding is high.

[0005]

In performing the work of grounding the solar cell modules, it is necessary to confirm whether or not each of the solar cell modules is properly grounded. Usually, the surface of the solar cell module is made of a polymer resin,
It is covered with a non-conductive surface protective material such as plastic or glass. Therefore, it is difficult to measure the ground resistance value from the front surface of the solar cell module, and it is necessary to measure the ground resistance value from the back surface of the solar cell module.

However, after the solar cell module is laid, the outer metal portion on the back of the solar cell module is hidden, and it is difficult to measure the ground resistance. Therefore,
Whenever one solar cell module is laid one by one, it is necessary to interrupt the solar cell module laying operation and measure the ground resistance. Therefore, workability is poor, the installation period of the solar cell module is lengthened, and the construction cost is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a measuring method and a measuring device capable of measuring a ground state with good workability.

[0008]

In order to achieve this object, a method for measuring the grounding state of a solar cell module according to the present invention comprises:
A step of arranging electrodes on a solar cell module in which a metal part to be grounded is connected to a ground electrode to form a capacitance between the metal part and an AC voltage between the electrode and the ground electrode; Detecting the flowing current and measuring the grounding state of the metal portion.

Further, the solar cell module grounding state measuring device of the present invention is arranged on a solar cell module in which a metal part to be grounded is connected to a ground electrode so as to form a capacitance between the metal part and the metal part. An electrode and a measuring means for applying an AC voltage between the electrode and a ground electrode and detecting a flowing current to measure a ground state of the metal portion.

In this configuration, if the metal part to be grounded of the solar cell module is securely connected to the grounding pole, the current flowing by applying the AC voltage can be detected, and the grounding state of the solar cell module can be changed. Can be measured. According to this, since it is not necessary to directly use the metal part to be grounded, it is possible to measure the grounding state with good workability by arranging electrodes on the surface side after the solar cell module is installed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment of the present invention, the measurement of the grounding state is performed by measuring the voltage value and frequency of an AC voltage applied between the electrode and the grounding electrode, and thereby determining the connection between the electrode and the grounding electrode. This is performed by using a relationship established among the current value of the current flowing between them, the capacitance value, and the wiring resistance value.

The target solar cell module is, for example, a building material-integrated solar cell module, the front surface of which is covered with a non-conductive surface protection material such as glass, polymer resin, or plastic, and the back surface as the metal portion. It has a conductor plate. The electrodes are planar and covered with an insulator.

In measuring the grounding state, the flowing current may be detected a plurality of times while changing the frequency of the AC voltage applied between the electrode and the grounding electrode. According to this, even when the capacitance between the electrode and the metal part is not known, the ground state of the solar cell module can be measured.

Further, the measurement result of the grounding state is notified to the measurer as a warning by a buzzer or displayed on a liquid crystal display or the like, so that the measurer can easily and accurately confirm the grounding state of the solar cell module. You may be able to.

[0015]

[Embodiment 1] FIG. 1 is a schematic diagram showing a method and an apparatus for measuring a ground state of a solar cell module according to a first embodiment of the present invention, and FIG. 3 is a schematic block diagram of this apparatus. As shown in these figures, this device forms a capacitance between a roof steel plate 11 and a roof steel plate 11 on a solar cell module 10 in which a roof steel plate 11 to be grounded is connected to a ground pole 50 by a ground wire 51. A conductor plate 20 serving as an electrode to be disposed, an AC standard voltage generator 30 for applying an AC voltage between the conductor plate 20 and the ground electrode 50, and a high-frequency ammeter 40 for detecting a current flowing thereby. Prepare. FIG.
Among them, 61 is an arithmetic control means for measuring the grounding state based on the voltage value and frequency of the AC voltage applied by the AC standard voltage generator 30 and the current value measured by the AC standard voltage generator 30, and 62 is the arithmetic control means. Display means for displaying the measurement results.

FIG. 2 is a detailed cross-sectional view of the building material integrated solar cell module 10 (Canon amorphous silicon solar cell module SR-02) whose grounding state is measured. As shown in FIG. 2, the solar cell module 10 has a back surface reflective layer 14, an amorphous silicon semiconductor layer 15, and a transparent conductive layer 16 sequentially laminated on a solar cell substrate 13 (here, a stainless steel substrate). Are laminated on a roof steel plate 11 with an insulating layer 12 interposed therebetween, and covered with a surface protection material 17 to be modularized. As shown in FIG. 1, the roof steel plate 11 is connected to a ground electrode 50 using a conductor (earth wire) 51.

The grounding state of the solar cell module 10 was measured as follows. First, as shown in FIG. 1, a 10 cm × 10 cm conductor plate 20 was placed as an electrode on the surface of a solar cell module 10 without cells. By placing the conductor plate 20 on the solar cell module 10, the roof steel sheet 11 on the back of the solar cell module
And the conductor plate 20 function as a capacitor having a capacitance C [F].

Next, a voltage of 10 [V] and a frequency of 1 V are applied between the ground electrode 50 and the conductor plate 20 by the AC standard voltage generator 30.
An alternating voltage of 00 [kHz] was applied, and the alternating current flowing between the ground electrode 50 and the conductor plate 20 was measured by the high-frequency ammeter 40. If the applied AC voltage is too high in voltage and frequency, it is dangerous and a large power supply device is required. Therefore, the voltage is 500 V or less and the frequency is 1 MHz or less. It is desirable.
The measured current value was 2.51 × 10 ^-1 [A].

Next, the capacitance C between the roof steel plate 11 and the conductor plate 20 at a frequency of 100 [kHz] was measured by a capacitance measuring device. The measured capacitance C was 40 [PF].

Next, based on the above-described applied voltage value, frequency, measured current value, and capacitance, the solar cell module 1
The wiring resistance value _RL between 0 and the ground electrode 50 was determined. The obtained wiring resistance value R _L [Ω] was 1.6 [Ω]. From this result, it can be seen that the solar cell module 10 is securely connected to the ground electrode. Note that the wiring resistance value R _L [Ω] can be obtained by the following equation. This formula can be easily derived from Ohm's law.

[0021]

(Equation 1) For comparison, the solar cell module 10 and the ground electrode 5
The same measurement was performed by removing the conducting wire 51 connected between 0. As a result, since no current flows between the ground electrode 50 and the conductor plate 20, the ground resistance R _L = ∞ according to the above equation, and it was confirmed that the solar cell module 10 was not connected to the ground electrode 50.

Further, by displaying the above measurement results on the display means 62 such as a liquid crystal display, the measurer can accurately measure the grounding state of the solar cell module. In addition, the alarm means such as a buzzer emits a normal sound when the solar cell module 10 is securely connected to the ground electrode 50, and emits an abnormal sound when the solar cell module 10 is not connected, so that measurement can be performed with higher workability. it can.

As described above, the conductor plate 20 is placed on the solar cell module 10, an AC voltage is applied from the AC voltage source 30 between the ground electrode 50 and the conductor plate 20, and the current flowing at that time is measured by the ammeter 40. Thus, the ground state of the solar cell module 10 can be measured from the surface of the solar cell module 10.

In the present embodiment, an amorphous silicon solar cell manufactured by Canon was used. However, the present invention is not limited to this, and it is needless to say that the present invention can be applied to a solar cell module of single crystal, polycrystal, or the like. . Further, in this embodiment, the solar cell module 10 is
Is placed on the surface portion without cells, but measurement can be made by placing it on a portion with cells.

Second Embodiment Next, a second embodiment of the present invention (a measurement example in a solar cell array on a roof) will be described. In this embodiment, 120 building material-integrated solar cell modules 10 (Canon amorphous silicon solar cell module SR-02) used in the first embodiment are used.

First, this solar cell module 10 is
The solar cell array was laid on the roof so as to be in series and 6 in parallel, to constitute a 3 kW solar cell array. Of this solar cell array,
Each of the five parallel solar cell modules 10 was connected to the ground electrode 50 using the ground wire 51, and the remaining one parallel solar cell module 10 was not connected to the ground electrode 50. At this time, each solar cell module 1 connected to the ground electrode 50
The ground resistance value of 0 was 30 [Ω].

Next, with respect to the solar cell module 10 connected to the ground electrode 50, first, a 10 cm × 10 cm conductive plate 20 is placed as an electrode on the surface of the solar cell module 10 without cells, and the AC standard voltage generator 30 is used. An AC voltage having a voltage of 10 [V] and a frequency of 100 [kHz] is applied between the ground electrode 50 and the conductor plate 20.
0 and the high-frequency ammeter 4
Measured by 0. The measured current value is 2.51 × 1
0 ^-1 [A].

Next, the capacitance C between the roof steel plate 11 on the back surface of the solar cell module 10 and the conductor plate 20 at a frequency of 100 [kHz] was measured by a capacitance measuring device. The capacitance C was 40 [PF].

The wiring resistance R _L [Ω] between the solar cell module and the ground electrode was determined from the above voltage value, frequency, current value, and capacitance. The wiring resistance R _L [Ω] is 1.6.
[Ω]. This indicates that the solar cell module 10 is securely connected to the ground electrode 50. In addition,
The wiring resistance value _RL can be obtained by the equation 1 as in the first embodiment.

When the same measurement was performed on the solar cell module 10 not connected to the ground electrode 50, no current flows between the ground electrode 50 and the conductor plate 20, so that the wiring resistance R _L = ∞, and It was confirmed that the battery module 10 was not connected to the ground electrode 50.

As described above, according to the method of the present invention, it is possible to measure the grounding state of the solar cell module similarly in the case of the solar cell module laid on the roof. Normally, when laying on the roof a solar cell module whose surface is covered with non-conductive surface protection material,
Since the outer metal part on the back surface of the solar cell module is hidden, it is extremely difficult to check the grounding state of the solar cell module. However, according to the present invention, even after installation, the grounding state of the solar cell module can be confirmed from the surface of the solar cell module, which is very convenient.

Embodiment 3 Next, a third embodiment of the present invention will be described. In the present embodiment, the grounding state in a case where it is impossible to measure the capacitance C between the roof steel plate 11 and the conductor plate 20 on the back surface of the solar cell module in advance, such as several years after the installation of the solar cell module. Regarding confirmation. In the present embodiment, a solar cell array similar to that of Embodiment 2 is formed on a roof, and each solar cell module is connected to a ground pole by a ground wire.

FIG. 4 shows an outline of a method for measuring the grounding state of a solar cell module according to this embodiment. 10c as shown in FIG.
An m × 10 cm conductor plate 20 is placed on a portion of a cell of the solar cell module 10, and a voltage of 10 [V] is applied between the ground electrode 50 and the conductor plate 20 by an AC standard voltage generator 30.
An AC voltage having a frequency of 80 [kHz] was applied, and an AC current flowing between the ground electrode 50 and the conductive plate 20 was measured by the high-frequency ammeter 40. The measured current value is 3.01
× 10 ^-1 [A]. Next, the ground electrode 50 and the conductor plate 2
0 to 100 [kHz]
z], and the current was measured again. As a result, the current value was 3.76 × 10 ⁻¹ [A]. Based on the above results, the wiring resistance R _L [Ω] of the solar cell module, the roof steel plate 11 and the conductor plate 2 on the back of the solar cell module
When the capacitance C between zero was determined, the wiring resistance R _L =
1.8 [Ω] and capacitance C = 60 [PF] were obtained.

As described above, different voltages are applied between the roof steel plate 11 and the conductor plate 20 on the back surface of the solar cell module,
By performing the measurement a plurality of times, the grounding state of the solar cell module 10 can be confirmed even when the capacitance between the solar cell module 10 and the conductor plate 20 is not known in advance. Further, since the capacitance between the solar cell module 10 and the conductor plate 20 can be measured, the state of the surface of the solar cell module 10 such as peeling of the surface protection material can be examined from the change in the capacitance C, Danger such as electric shock can be prevented. In this embodiment, the conductor plate 2 is placed on a portion of the solar cell module 10 where a cell is present.
Although 0 is arranged, it is needless to say that it can be arranged on a portion having no cell.

Embodiment 4 Next, a fourth embodiment of the present invention will be described. In this embodiment, an LCR meter (HI
OKI3520LCR HiTester). This measuring instrument is very convenient because it can measure the capacitance, wiring resistance, and the like required for implementing the present invention. Actually, the same measurement was performed by an LCR meter using the same solar cell module 10 and conductive plate 20 as in Example 1, and when the solar cell module 10 was grounded, at a frequency of 100 [kHz], The wiring resistance value R _L = 1.8 [Ω] and the capacitance C = 40 [PF], and almost the same values as in Example 1 were obtained. When the solar cell module 10 is not grounded, the wiring resistance R _L = ∞, and the solar cell module 10
It was confirmed that it was not connected to 0. Even when only the LCR meter is used as the measuring instrument and the power source as in the present embodiment, the grounding state of the solar cell module 10 can be easily and accurately confirmed.

As described above, in each embodiment, the non-conductive surface protection member 17 of the solar cell module 10, the outer metal part 11 of the solar cell module 10, and the conductor plate 20 are configured to have capacitance. The greatest feature is that the ground state can be measured from the surface of the solar cell module 10 even in the solar cell module 10 whose surface is covered with the non-conductive surface protective material 17 by applying an AC voltage thereto and measuring the impedance. It has become.
A wide variety of embodiments are possible for the measuring instrument and power supply described in each embodiment.

[0037]

As described above, according to the present invention, it is not necessary to measure the grounding resistance value each time one solar cell module is laid one by one as in the prior art. The grounding state can be measured from the surface of the solar cell module. Therefore, the workability can be greatly improved, the installation work period of the solar cell module can be shortened, and the work cost can be reduced. Further, by displaying the measurement result or notifying the result as an alarm, the working time can be further reduced. Furthermore, by performing measurements multiple times while changing the frequency of the AC voltage applied between the electrodes arranged on the solar cell module and the ground electrode, the roof can be mounted even after several years have passed since the solar cell module was laid. The grounding state can be measured without removing the solar cell module, and the capacitance between the solar cell module and the electrode can also be measured. Therefore, from the change in the capacitance between the solar cell module and the electrode, an abnormality on the surface of the solar cell module, such as the peeling of the surface protective material, can be found. As described above, when the grounding state of the solar cell module is measured, a remarkable effect is obtained by using the present invention.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a method and an apparatus for measuring a ground state of a solar cell module according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a solar cell module measured by the method and apparatus of FIG.

FIG. 3 is a schematic block diagram of the apparatus of FIG. 1;

FIG. 4 is a configuration diagram illustrating a method for measuring a ground state of a solar cell module according to a third embodiment of the present invention.

[Explanation of symbols]

10: Solar cell module, 11: Steel plate for roof, 12:
Insulating layer, 13: stainless steel substrate, 14: back reflection layer, 1
5: amorphous silicon semiconductor layer, 16: transparent conductive layer, 17: surface protective material, 20: conductor plate, 30: AC voltage source, 40: ammeter, 50: ground electrode, 51: ground wire, 6
0: measuring device, 61: arithmetic control means, 62: display device.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoki Manabe 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (15)

[Claims] 1. A step of arranging electrodes on a solar cell module in which a metal part to be grounded is connected to a ground electrode so as to form a capacitance between the metal part and a ground electrode, Applying an AC voltage to the metal part and detecting a flowing current to measure a grounding state of the metal part. 2. The method according to claim 1, wherein the measurement of the ground state includes a voltage value and a frequency of an AC voltage applied between the electrode and a ground electrode;
2. The method according to claim 1, wherein the current value of the current flowing between the electrode and the ground electrode, the value of the capacitance, and the relationship established between the wiring resistance values are used. 3. How to measure the ground condition of solar cell module 3. The method according to claim 1, wherein the solar cell module is a building material integrated solar cell module. 4. The solar cell module according to claim 1, wherein a surface of the solar cell module is covered with a non-conductive surface protecting material such as glass, a polymer resin, or plastic.
The solar cell module grounding state measuring method according to any one of the above. 5. The method for measuring a ground state of a solar cell module according to claim 1, wherein the solar cell module has a conductor plate as the metal part on a back surface. 6. The method for measuring the ground state of a solar cell module according to claim 1, wherein the electrode is planar. 7. The method for measuring a ground state of a solar cell module according to claim 1, wherein the electrode is covered with an insulator. 8. The method according to claim 1, wherein in the step of measuring the ground state, a flowing current is detected a plurality of times while changing a frequency of an AC voltage applied between the electrode and a ground electrode. 8. The method for measuring the ground state of a solar cell module according to any one of items 7 to 7. 9. The method for measuring the ground state of a solar cell module according to claim 1, further comprising an alarming step of notifying a measurement result of the ground state to a measurer. 10. The method for measuring the ground state of a solar cell module according to claim 1, further comprising a display step of displaying a measurement result of the ground state. 11. An electrode disposed on a solar cell module having a metal part to be grounded connected to a ground electrode to form a capacitance between the metal part and the electrode, and between the electrode and the ground electrode. Measuring means for applying an AC voltage and detecting a flowing current to measure a grounding state of the metal portion, wherein the grounding state measuring apparatus for a solar cell module is provided. 12. The solar cell module grounding state measuring apparatus according to claim 11, wherein the electrode is planar. 13. The solar cell module grounding state measuring apparatus according to claim 11, wherein the electrode is covered with an insulator. 14. An apparatus according to claim 11, further comprising alarm means for informing a measurer of the measurement result of said ground contact state.
The solar cell module grounding state measuring device according to any one of claims 13 to 13. 15. The solar cell module ground state measuring apparatus according to claim 11, further comprising display means for displaying the ground state measurement result.