JPH09102622A - Failure detector of solar cell module of solar power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely detect the failure of a solar cell module by installing a circuit which generates a failure output corresponding to the current flowing state of a current relay operated by a current flowing through a bypass diode when it continues for a specific period. SOLUTION: When a solar cell module 7 does not generate electric power on account of failure, a bypass diode 8 turns on, and a current generated by other solar cell module 7 in the same string flows through the diode. In this case, a current relay 10 also operates and shuts a contact 10a. The current relay 10 operates also when the solar cell module 7 is not temporarily irradiated with light. In order to cope with it, each of the output contacts 10a is connected with an output circuit 11 provided with a timing circuit like an on-delay timer. Thereby a failure output is generated only when the operation of the current relay 10 has continued for a specific period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure detection device for individually detecting a failure of a solar cell module that constitutes a solar cell array used in a solar power generation system.

[0002]

2. Description of the Related Art A solar power generation system 1 shown in FIG. 2 supplies electric power generated by a solar cell array 2 to a power conditioner 4 having an inverter or the like through a blocking diode 3 for preventing backflow, and this power conditioner 4 The converted voltage of a predetermined format is used to supply power to the private facility 5 and to connect to the grid 6.

The solar cell array 2 is a panel-shaped solar cell module 7 manufactured as a minimum mounting unit.
3 are arranged side by side on a mounting base, and as shown in FIG. 3, a string 9 in which a plurality of solar cell modules 7 in which bypass diodes 8 are connected in parallel are connected in series is further connected in parallel and is required. The voltage and current are as large as

The bypass diode 8 is used for another solar cell module of the same string, as shown in FIG. 4, when a particular solar cell module 7'is shaded by solar radiation or when a current stops flowing due to a failure. It is provided to bypass the current generated in 7. When each solar cell module is generating power normally, the generated voltage is applied as a reverse bias voltage to the bypass diode 8 connected in parallel with it, so that the bypass diode 8 maintains the cutoff state.

[0005]

The above-mentioned solar cell array 2
If the solar cell module 7 that constitutes the above-mentioned module fails due to breakage, disconnection, or the like, even if another solar cell module 7 in the same string is generating power, the voltage generated in that string 9 is generated in the other string 9 connected in parallel. It becomes lower than the voltage and the supply current becomes smaller. For this reason, the power generation amount of the string 9 further decreases more than the ratio of the failed solar cell module 7 to the string 9.

Since it is not preferable to continue the operation in the state where the power utilization rate of the solar cell module 9 is lowered in this way, when a failure occurs, the solar cell module 7 must be replaced and repaired at an early stage. .

However, this failure detection is not easy because the output of each solar cell module 7 constantly fluctuates according to the weather conditions. For example, each solar cell module 7
If you try to determine the presence or absence of failure by actually measuring the generated voltage of
It is a task to check the generated voltage while considering the relationship with the individual solar radiation amount. This is too costly to be practical. Therefore, an object of the present invention is to provide a device capable of reliably and quickly detecting a failure of a solar cell module.

[0008]

A failure detecting device for a solar cell module of a solar power generation system provided by the present invention is
A solar cell array in which a plurality of solar cell modules connected in parallel with bypass diodes are connected in series to form a string of solar cells, and a plurality of these strings are connected in parallel to obtain a predetermined output voltage and output current. In a solar power generation system having, a current relay that is inserted and connected in series to a bypass circuit of each solar cell module and that operates by a current when a bypass diode is energized,

When the energized state of the current relay continues for a predetermined time, an output circuit for outputting an operation abnormality of the solar cell module corresponding thereto is provided.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows the solar cell array 2 described with reference to FIG.
In each of the bypass diodes 8, 8, ..., Which constitute the bypass circuit of the solar cell module 7, the current relay 1
1 shows a solar cell array 2'in which 0, 10, ... Are connected in series.

The operating points of these current relays 10, 10, ... Are set to a level at which the bypass current (forward current) flowing through the bypass diode 8 can be detected.

In this configuration, when each solar cell module 7 is normally generating power, each bypass diode 8 is reverse-biased by its voltage and does not energize this bypass circuit, so the current relays 10, 10, … Also doesn't work.

However, if the solar cell module 7 does not generate power due to a failure, no reverse bias voltage is applied to the bypass diode 8 connected in parallel with it, so that the bypass diode 8 is energized and the other solar cell modules 7 in the same string are connected. Energize the current generated in. At this time, the current relay 10 also operates and its contacts 10a, 10
Close a, ...

In the operation of the current relay 10, the solar cell module 7 is temporarily not exposed to light due to a cloud flow or a shadow of a surrounding building in addition to a failure due to damage or disconnection of the solar cell module. It may occur. In order to deal with this, each output contact 10a, 10a, ... Is connected to an output circuit 11 having a timed circuit such as an on-delay timer, and a fault output is generated only when the operation of the current relay 10 continues for a certain period of time. . This fault output is, for example,
It is input to the management device of the solar power generation system as individual failure information of each solar cell module 7. In addition to this, it is also possible to input to a dedicated failure notification means such as lighting of a lamp or an alarm by a buzzer.

The delay time of the timed circuit is appropriately set in consideration of the length of time in the shadow caused by the size of surrounding buildings. With this setting,
The defective solar cell module can be accurately detected.

The current relay 10 can omit the timed element in the output circuit 11 by using a timer relay having a timed element in itself. Further, the current relay 10 has a common contact with a plurality of windings,
By inserting and connecting each winding in series to each bypass circuit of each solar cell module and connecting a common contact when a failure occurs in one of the solar cell modules, multiple solar cell modules are grouped together. It is also possible to detect failures.

[0018]

According to the present invention, the failure of the solar cell module is detected by detecting the bypass current of the bypass diode connected in parallel with the solar cell module by the current relay. There is no ambiguity as in the case of measuring the voltage generated by the battery module, failure can be accurately detected, and the solar cell array can be easily maintained and managed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a failure detection device for a solar cell module of the present invention.

FIG. 2 is a block diagram showing a general configuration of a solar power generation system.

FIG. 3 is a circuit diagram showing a connection state of a conventional solar cell array.

FIG. 4 is a diagram showing a current path during normal operation and a current path during failure in a solar cell module in which bypass diodes are connected in parallel.

[Explanation of symbols]

 1 Solar Power Generation System 2 Solar Cell Array 3 Blocking Diode 4 Power Conditioner 7 Solar Cell Module 8 Bypass Diode 9 Solar Cell String 10 Current Relay 10a Current Relay Contact 11 Output Circuit

Claims (1)

[Claims] 1. A solar cell module comprising a plurality of bypass diodes connected in parallel, which are connected in series to form a string of solar cells. The strings are connected in parallel so that a predetermined output voltage and output current can be obtained. In a solar power generation system having a solar cell array, a current relay that is inserted and connected in series to the bypass circuit of each solar cell module and operates by the current when the bypass diode is energized, and the energized state of the current relay is for a predetermined time. A failure detection device for a solar cell module of a solar power generation system, comprising an output circuit that outputs a failure of the corresponding solar cell module when continued.