CN204044246U - A kind of square formation insulation impedance detection system of photovoltaic generating system - Google Patents

Abstract

The utility model discloses a square array insulation resistance detection system of a photovoltaic power generation system, which comprises a positive terminal sampling circuit, a negative terminal sampling circuit, and a microprocessor to calculate the sampling signal to obtain the positive pole-to-ground insulation resistance of the photovoltaic square array and the negative pole-to-ground The insulation resistance value is compared with the setting value input to the microprocessor by the insulation resistance value input circuit for judgment and alarm output. It can measure and calculate the DC insulation resistance between the input terminal of the power generation system connected to the photovoltaic array and the ground. When the insulation resistance does not meet the limit requirements, it will indicate the fault and report the fault to the external controller. It can effectively ensure the insulation performance detection of the photovoltaic power generation system's battery panel square array. It is a simple, reliable and fast detection system that provides a strong guarantee for the safe operation of the photovoltaic power generation system.

Description

A square array insulation resistance detection system for a photovoltaic power generation system

technical field

The utility model belongs to the field of electric energy conversion, and in particular relates to a square array insulation resistance detection system suitable for a photovoltaic power generation system. the

Background technique

Among many new energy sources, solar energy has become the focus of people's attention due to its unique advantages. Abundant solar radiant energy is inexhaustible, non-polluting, and free-to-use important energy, and solar energy is widely distributed and easy for people to use; it is one of the most direct clean energy available to human beings. the

With the increase in capacity and quantity of photovoltaic power generation systems, various functions of photovoltaic inverters have been continuously improved, including the detection of the insulation resistance of the array. The insulation performance of the square array mainly includes two aspects: one is that the cable connecting the battery boards is accidentally damaged or the insulation layer is aging during the process of processing and laying; the other is the aging of the insulation layer of the battery board itself. Once the insulation resistance value of the square array is lower than the normal value, it will directly affect the operation safety of the entire power generation system. the

The certification technical specification of Beijing Jianheng Certification Center clearly states that the inverter connected to the ungrounded photovoltaic array should measure the input terminal of the module array and the ground before the system is started. DC insulation resistance between. When the insulation resistance does not meet the requirements of the limit value, a fault should be indicated for the inverter with isolation, but other actions and operations can still be performed during the fault; If the requirements are not met, a fault shall be indicated and its access to the grid shall be restricted. the

Contents of the invention

The technical problem to be solved by the utility model is to provide a simple, reliable and fast square array insulation resistance detection system applied in the photovoltaic power generation system to accurately measure the insulation of the photovoltaic square array to the ground before the photovoltaic inverter grid-connected power generation is started. Impedance, to protect the safe operation of the system. the

In order to solve the above-mentioned technical problems, the technical solution of the present utility model is a square matrix insulation impedance detection system of a photovoltaic power generation system, including: a positive terminal sampling circuit, one end connected to the positive terminal of the photovoltaic power generation system, and the other end connected to the positive terminal of the photovoltaic power generation system. Sampling is performed to obtain the first sampling signal and input to the microprocessor; the negative terminal sampling circuit, one end is connected to the negative terminal of the photovoltaic power generation system, and the other end is grounded, and the negative terminal of the photovoltaic power generation system is sampled to obtain the second sampling signal and input to the microprocessor; insulation The output end of the resistance value input circuit is connected to the microprocessor; the alarm output circuit and the alarm indicator circuit are connected to the output end of the microprocessor. the

Preferably, the positive terminal sampling circuit includes a first sampling resistor with one end grounded, the other end of the first sampling resistor is connected to two outputs, one output is connected to the first relay and the first current limiting resistor in sequence, and the first current limiting resistor is connected to On the positive pole of the photovoltaic array, the coil of the first relay is connected to the microprocessor, and the microprocessor controls its current on and off; the other output of the first sampling resistor is connected in sequence with the same direction amplifier circuit, the first voltage follower circuit and A first filter circuit, the output terminal of the first filter circuit is connected to the A/D conversion input port of the microprocessor. the

Preferably, the non-inverting amplifying circuit is composed of an operational amplifier LM348 and a resistor. The co-inverting input terminal of the operational amplifier LM348 is connected to the first sampling resistor, and the inverting input terminal is grounded through the resistor; the first voltage follower circuit is composed of an operational amplifier OP484ES; A filter circuit is a filter circuit constructed of resistors and capacitors; the first relay includes a relay body and a coil control circuit connected to the I/O interface of the relay body and the microprocessor. the

Preferably, the negative terminal sampling circuit includes a second sampling resistor with one end grounded, the other end of the second sampling resistor is connected to two outputs, one output is connected to the second relay and the second current limiting resistor in sequence, and the second current limiting resistor is connected to On the negative pole of the photovoltaic array, the coil of the second relay is connected to the microprocessor, and the microprocessor controls its current on and off; the other output of the second sampling resistor is connected in turn with an inverting amplifier circuit, a second voltage follower circuit and A second filter circuit, the output end of the second filter circuit is connected to the A/D conversion input port of the microprocessor. the

Preferably, the reverse amplifying circuit is composed of an operational amplifier LM348 and a resistor. The reverse input terminal of the operational amplifier LM348 is connected to the first sampling resistor, and the reverse input terminal is grounded through the resistor; the second voltage follower circuit is formed by the operational amplifier OP484ES; The second filter circuit is a filter circuit constructed of resistors and capacitors; the second relay includes a relay body and a coil control circuit connected to the I/O interface of the relay body and the microprocessor. the

Preferably, the insulation resistance value input circuit includes a circuit composed of two 8421 encoders. the

Preferably, the alarm output circuit includes two transistor output photocouplers TLP281-4. the

Preferably, the microprocessor is also connected with an alarm indicator circuit, and the alarm indicator circuit is composed of two light-emitting diodes and a resistor. the

The beneficial effect of the utility model is that it can measure and calculate the DC insulation resistance between the input end of the power generation system connected to the photovoltaic square array and the ground, and when the insulation resistance does not meet the limit value requirements, it will indicate a fault and report to the external controller Fault. It can effectively ensure the insulation performance detection of the photovoltaic power generation system's battery panel array. It is a simple, reliable and fast detection system that provides a strong guarantee for the safe operation of the photovoltaic power generation system. the

Description of drawings

Fig. 1 is the system schematic diagram of the utility model embodiment;

Fig. 2 is the positive terminal sampling circuit of the utility model embodiment;

Fig. 3 is the negative terminal sampling circuit of the utility model embodiment;

Fig. 4 is the insulation impedance comparison value input circuit of the utility model embodiment;

Fig. 5 is the warning lamp circuit of the utility model embodiment;

Fig. 6 is the alarm output circuit of the utility model embodiment;

Fig. 7 is a flowchart of the internal software algorithm of the microprocessor of the embodiment of the present invention. the

In the picture:

1. The first impedance to be measured 2, the second impedance to be measured 3, the first sampling resistor 4, the first current limiting resistor 5, the same direction amplifier circuit 6, the first voltage follower circuit 7, the first filter circuit 8, the first Relay 9, second sampling resistor 10, second current limiting resistor 11, reverse amplifier circuit 12, second voltage follower circuit 13, second filter circuit 14, second relay 15, microprocessor 16, insulation resistance value input circuit 17. Alarm output circuit 18. Alarm indicator circuit

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described further. the

As shown in Figures 1 to 6, a first impedance 1 to be measured is connected between the positive terminal of the photovoltaic array and the earth; a second impedance 2 to be measured is connected between the negative terminal of the photovoltaic array and the earth. A square array insulation resistance detection system of a photovoltaic power generation system, comprising: a positive terminal sampling circuit, one end is connected to the positive terminal of the photovoltaic power generation system, and the other end is grounded, and the positive terminal of the photovoltaic power generation system is sampled to obtain the first sampling signal and input to the microprocessor 15 The negative terminal sampling circuit, one end is connected to the negative terminal of the photovoltaic power generation system, and the other end is grounded, and the negative terminal of the photovoltaic power generation system is sampled to obtain the second sampling signal and input to the microprocessor 15; the output terminal of the insulation resistance value input circuit 16 is connected to the microprocessor Device 15; Alarm output circuit 17 and alarm indicator circuit 18 are connected to the output end of microprocessor 15. the

As shown in Figure 1 and Figure 2, the positive terminal sampling circuit includes a first sampling resistor 3 with one end grounded, the other end of the first sampling resistor 3 is connected to two outputs, and one output is sequentially connected to the first relay 8 and The first current-limiting resistor 4, the first current-limiting resistor 4 is connected to the positive pole of the photovoltaic array, and the coil of the first relay 8 is connected to the microprocessor 15 to control its current on-off by the microprocessor 15; the first sampling resistor 3 The other output is sequentially connected with the same direction amplifier circuit 5, the first voltage follower circuit 6 and the first filter circuit 7, the output end of the first filter circuit 7 is connected to the microprocessor 15A/D conversion input port, and the same direction amplifier circuit 5 It is composed of an operational amplifier LM348 and a resistor. The same input terminal of the operational amplifier LM348 is connected to the first sampling resistor 3, and the reverse input terminal is grounded through the resistor; the first voltage follower circuit 6 is composed of an operational amplifier OP484ES; the first filter circuit 7 is a resistor A filter circuit built with capacitors; the first relay 8 includes a relay body and a coil control circuit connected to the relay body and the I/O interface of the microprocessor 15 . the

The negative terminal sampling circuit shown in Figure 1 and Figure 3, the negative terminal sampling circuit includes a second sampling resistor 9 with one end grounded, the other end of the second sampling resistor 9 is connected to two outputs, and one output is connected to the second relay 14 and the second relay 14 in sequence. The second current-limiting resistor 10, the second current-limiting resistor 10 is connected to the negative pole of the photovoltaic square array, and the coil of the second relay 14 is connected to the microprocessor 15 to control its current on-off by the microprocessor 15; the second sampling resistor 9 The other output is sequentially connected with an inverse amplifier circuit 11 , a second voltage follower circuit 12 and a second filter circuit 13 , and the output end of the second filter circuit 13 is connected to the A/D conversion input port of the microprocessor 15 . The reverse amplifying circuit 11 is constructed by an operational amplifier LM348 and a resistor. The reverse input terminal of the operational amplifier LM348 is connected to the first sampling resistor 3, and the reverse input terminal is grounded through the resistor; the second voltage follower circuit 12 is formed by the operational amplifier OP484ES; the second The filter circuit 13 is a filter circuit constructed of resistors and capacitors; the second relay 14 includes a relay body and a coil control circuit connected to the relay body and the I/O interface of the microprocessor 15 . the

Microprocessor 15 is also connected with insulation resistance value input circuit 16, alarm output circuit 17 and warning lamp circuit 18, and insulation resistance value input circuit 16 as shown in Figure 4 comprises the circuit that two 8421 encoders are formed, as shown in Figure 6 The alarm indicator output circuit 17 includes two transistor output optocouplers TLP281-4, and the alarm indicator circuit 18 is composed of two light-emitting diodes and resistors as shown in FIG. 5 . the

The microprocessor 15 calculates the sampling signal to obtain the insulation resistance value of the positive electrode to the ground of the photovoltaic array and the insulation resistance value of the negative electrode to the ground, and compares it with the set value input to the microprocessor 15 by the insulation resistance value input circuit 16, and is connected to The alarm output circuit 17 of the microprocessor 15 outputs an alarm signal to an external controller. the

The working process of this embodiment is: first only close the first relay 8, the ground voltage of the first sampling resistor 3 in the positive terminal sampling circuit is input through the non-inverting amplifier circuit, the first voltage follower circuit 6 and the first filter circuit 7 Go to the microprocessor 15 to convert the analog quantity to the digital quantity, and obtain the positive terminal sampling resistance voltage value;

Disconnect the first relay 8 again, only close the second relay 14, the ground voltage of the second sampling resistor 9 in the negative terminal sampling circuit is input to The microprocessor 15 converts the analog quantity to the digital quantity, and obtains the negative terminal sampling resistance voltage value;

Finally, close the first relay 8 and the second relay 14 at the same time, the ground voltage value of the first sampling resistor 3 and the second sampling resistor 9, in the microprocessor 15, calculate the positive pole pair insulation resistance and the negative pole pair of the photovoltaic array through the formula Ground insulation resistance, compare the calculated value with the set value, and finally output through the alarm indicator circuit 18 and the alarm output circuit 17. When no detection is needed, both the positive and negative terminal relays are disconnected to ensure the safety and stability of the system run. the

As shown in Figure 7, the microprocessor 15 calculates the method for calculating the positive pole-to-insulation resistance Rx1 of the photovoltaic array and the negative pole-to-ground insulation resistance Rx2 as follows: the resistance values of the first current-limiting resistor 4 and the second current-limiting resistor 10 are both R1 , the resistance values of the first sampling resistor 3 and the second sampling resistor 9 are both R2; the first relay 8 is marked as K1, and the second relay 14 is marked as K2. the

Firstly, the square matrix insulation resistance reference value R is input into the microprocessor 15 through the insulation resistance value input circuit 16 . When the open-circuit voltage of the photovoltaic inverter reaches the starting condition, a square array insulation resistance measurement command will be issued, which is input into the microprocessor 15 through an input signal, and the microprocessor 15 will enter the insulation resistance detection processing program. the

The microprocessor 15 issues a command to close _{the first relay 8, and measures the ground voltage of the first sampling resistor 3 as the sampling voltage V 1 after} a certain time interval. The second relay 14 command, after a certain time interval, measure the ground voltage of the second sampling resistor 9 as the sampling voltage V ₂ , after obtaining the voltage V ₂ , issue a command to close the first relay 8 and the second relay 14, and simultaneously after a certain time interval Measure the ground voltage of the first sampling resistor 3 as the sampling voltage V′ ₁ and the ground voltage of the second sampling resistor 9 as the sampling voltage V′ ₂ .

When only the first relay 8 is closed in the above process, according to the circuit principle, it can be obtained:

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; [</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

When only closing the second relay 14 in the above process, according to the circuit principle, it can be obtained:

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; [</span>\frac{<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

From formula (1) and formula (2), we can get

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}\\ {\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

It can be seen from (3) that the insulation resistance R _X1 and R _X2 must be calculated, wherein the value of V _dc is obtained by the following method, and the first relay 8 and the second relay 14 are closed at the same time, and the value of V _dc can be obtained according to the circuit principle for:

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; [</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Bring the DC V _dc formula calculated in (4) into the formula (3), and after simplification, we can get

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; [</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}{<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}\\ {\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; [</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Finally, compare the calculated positive insulation resistance and negative insulation resistance values of the photovoltaic array with the reference value R set by the insulation resistance value input circuit 16 input to the microprocessor 15. If it is lower than the reference value R, it means that the simulated insulation resistance has failed. , the fault indication signal is made by the alarm indicator light, and the fault signal is output to the external controller by the alarm output circuit 17; otherwise, the normal signal of the insulation of the phalanx is output. the

It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should belong to the protection scope of the appended claims of the present invention. the

Claims (8)

1. A square matrix insulation resistance detection system of a photovoltaic power generation system, characterized in that it includes: a positive terminal sampling circuit, one end is connected to the positive terminal of the photovoltaic power generation system, and the other end is grounded, and the positive pole of the photovoltaic power generation system is sampled to obtain the first sampling signal And input microprocessor (15); Negative terminal sampling circuit, one end is connected to the negative terminal of photovoltaic power generation system, the other end is grounded, the negative pole of photovoltaic power generation system is sampled to obtain the second sampling signal and input microprocessor (15); Insulation resistance The output end of the value input circuit (16) is connected to the microprocessor (15); the alarm output circuit (17) and the alarm indicator circuit (18) are connected to the output end of the microprocessor (15). the 2. The square array insulation resistance detection system of a photovoltaic power generation system according to claim 1, characterized in that: the positive terminal sampling circuit includes a first sampling resistor (3) with one end grounded, the first sampling resistor (3) The other end is connected to two outputs, and one output is connected to the first relay (8) and the first current limiting resistor (4) in sequence, the first current limiting resistor (4) is connected to the positive pole of the photovoltaic array, and the first relay (8) The coil connected to the microprocessor (15) is controlled by the microprocessor (15) to turn on and off the current; the other output of the first sampling resistor (3) is connected with the same direction amplifier circuit (5) in sequence, and the first voltage follows The circuit (6) and the first filter circuit (7), the output end of the first filter circuit (7) is connected to the A/D conversion input port of the microprocessor (15). the 3. The phalanx insulation resistance detection system of a kind of photovoltaic power generation system according to claim 2, is characterized in that: in the same direction amplifier circuit (5) is constructed by operational amplifier LM348 and resistance, and operational amplifier LM348 is connected in the same direction input end The first sampling resistor (3), the reverse input terminal is grounded through the resistor; the first voltage follower circuit (6) is composed of an operational amplifier OP484ES; the first filter circuit (7) is a filter circuit built with resistors and capacitors; the first Relay (8) comprises relay body and is connected to the coil control circuit of the I/O interface of relay body and microprocessor (15). the 4. The square array insulation resistance detection system of a kind of photovoltaic power generation system according to claim 1 is characterized in that: the negative terminal sampling circuit comprises a second sampling resistor (9) with one end grounded, the second sampling resistor (9) The other end is connected to two outputs, one output is connected to the second relay (14) and the second current limiting resistor (10) in sequence, the second current limiting resistor (10) is connected to the negative pole of the photovoltaic array, and the second relay (14) The coil connected to the microprocessor (15) is controlled by the microprocessor (15) to turn on and off the current; the other output of the second sampling resistor (9) is sequentially connected with an inverting amplifier circuit (11), and the second voltage follows A circuit (12) and a second filter circuit (13), the output end of the second filter circuit (13) is connected to the A/D conversion input port of the microprocessor (15). the 5. the phalanx insulation resistance detection system of a kind of photovoltaic power generation system according to claim 4 is characterized in that: reverse amplifier circuit (11) is constructed by operational amplifier LM348 and resistance, and operational amplifier LM348 reverse input terminal is connected The first sampling resistor (3), the reverse input terminal is grounded through the resistor; the second voltage follower circuit (12) is formed by the operational amplifier OP484ES; the second filter circuit (13) is a filter circuit built by resistors and capacitors; the second The relay (14) includes a relay body and a coil control circuit connected to the I/O interface of the relay body and the microprocessor (15). the 6. The square array insulation resistance detection system of a photovoltaic power generation system according to claim 1, characterized in that: the insulation resistance value input circuit (16) includes a circuit composed of two 8421 encoders. the 7. The square array insulation resistance detection system of a photovoltaic power generation system according to claim 1, characterized in that: the alarm output circuit (17) includes two transistor output photocouplers TLP281-4. the 8. The phalanx insulation resistance detection system of a kind of photovoltaic power generation system according to claim 1, is characterized in that: microprocessor (15) is also connected with warning light circuit (18), warning light circuit (18) It consists of two LEDs and resistors. the