CN106370908A - Reliability monitoring system for optical current transformer - Google Patents

Abstract

A reliability monitoring system for optical current transformers belongs to the field of optical current transformers. The invention solves the problem that the reliability of existing optical current transformers cannot be verified. The light emitted by the LED light source of the present invention is divided into two beams of light by the optical fiber beam splitter, one light is input to the incident end of the optical current sensor, and the other light is transmitted to the collector; the optical signal through the optical current sensor is connected to the collector, and the optical fiber temperature sensor Both the temperature sensor and the secondary optical fiber temperature sensor are connected to the temperature modem through the optical fiber, and the temperature information obtained by the temperature modem is input into the collector through the optical fiber; the collector is connected to the merging unit, and the reliability data recording unit analyzes the data information of the merging unit to obtain the optical current sensor Working status information, LED light source status information, temperature information measured by the primary optical fiber temperature sensor and the secondary optical fiber temperature sensor, and record the data at fixed time intervals. The invention is used in power system.

Description

A Reliability Monitoring System of Optical Current Transformer

technical field

The invention belongs to the field of optical current transformers, in particular to a reliability monitoring system of optical current transformers.

Background technique

Optical current transformers have attracted widespread attention in power systems due to their advantages of no magnetic saturation, good insulation performance, and strong anti-interference ability. Optical current transformers have been increasingly used in smart substations, and their operational reliability , stability directly or indirectly affect the safe operation of smart substations.

There is still relatively little research on the reliability of optical current sensors at home and abroad, and there are no targeted reliability test standards and procedures, let alone a reliability system for optical current sensors. The optical current transformer based on the principle of optics is a product of optomechanical integration. Its reliability involves a wide range of factors, complex influencing factors, and numerous failure modes. Components, which are more complex, have not been proven for reliability and may require frequent repair or replacement.

Contents of the invention

The object of the invention is to solve the problem that the reliability of the existing optical current transformer cannot be verified, and provide a reliability monitoring system of the optical current transformer.

A reliability monitoring system for an optical current transformer according to the present invention includes a primary sensing unit, a secondary processing unit, and a reliability data recording unit, and a connection between the primary sensing unit, the secondary processing unit, and the reliability data recording unit Both are connected by optical fiber;

The primary sensing unit includes an optical current sensor and a primary optical fiber temperature sensor, and the secondary processing unit includes an LED light source, an optical fiber beam splitter, a collector, a secondary optical fiber temperature sensor, a temperature modem, and a merging unit;

The light emitted by the LED light source is divided into two beams through the optical fiber beam splitter. One light is input to the incident end of the optical current sensor through the optical fiber, and the other light is transmitted to the collector; the optical signal passing through the optical current sensor is connected to the collector through the optical fiber. The optical fiber temperature sensor and the secondary optical fiber temperature sensor are connected to the temperature modem through optical fiber, and the temperature information of the primary sensing unit and the secondary processing unit obtained by the temperature modem is input into the collector through the optical fiber; The unit is connected, and the reliability data recording unit analyzes the data information of the merging unit to obtain the working status information of the optical current sensor, the status information of the LED light source, the temperature information measured by the primary optical fiber temperature sensor and the secondary optical fiber temperature sensor, and Data is recorded at fixed time intervals.

The advantages of the present invention: the performance of the optical devices inside the optical current transformer is mostly a slowly changing process. After realizing the internal state monitoring of the optical current transformer and recording the sampling value data representing the operating state in real time, not only can it be realized in its Before a fault occurs, an alarm prompt is given, maintenance is reasonably arranged, and the recorded data can be used to evaluate the health status and service life of the optical current transformer. In this way, the operation reliability of the substation can be greatly improved, and the economic loss caused by the failure and power failure can be avoided. Therefore, it is necessary to establish a reliability monitoring system for optical current transformers to realize real-time monitoring and reliability life evaluation of optical current transformers, and to promote the practical application of optical current transformers in smart grids.

Monitoring the internal state of the optical current transformer and recording the data representing the operating state in real time can not only give an alarm prompt and arrange maintenance reasonably before it fails, but also use the recorded data to analyze the health status and service life of the optical current transformer. to evaluate. The application of the achievement of the invention can greatly improve the operation reliability of the substation, avoid the economic loss caused by the failure and power failure, and has important value for the practicality and popularization of the optical sensor.

Description of drawings

Fig. 1 is a schematic structural diagram of a reliability monitoring system for an optical current transformer according to the present invention.

detailed description

Specific Embodiment 1: This embodiment will be described below in conjunction with FIG. 1 . A reliability monitoring system for an optical current transformer described in this embodiment includes a primary sensing unit 1 , a secondary processing unit 2 and a reliability data recording unit 3 , the primary sensing unit 1, the secondary processing unit 2 and the reliability data recording unit 3 are all connected by optical fibers;

The primary sensing unit 1 includes an optical current sensor 1-1 and a primary optical fiber temperature sensor 1-2, and the secondary processing unit 2 includes an LED light source 2-1, an optical fiber beam splitter 2-2, a collector 2-3, and a secondary optical fiber temperature sensor 2-4, temperature modem 2-5 and merging unit 2-6;

The light emitted by the LED light source 2-1 is divided into two beams of light through the optical fiber beam splitter 2-2, one light is input into the incident end of the optical current sensor 1-1 through the optical fiber, and the other light is transmitted to the collector 2-3; The optical signal of the sensor 1-1 is connected to the collector 2-3 through an optical fiber, the primary optical fiber temperature sensor 1-2 and the secondary optical fiber temperature sensor 2-4 are connected to the temperature modem 2-5 through the optical fiber, and the temperature modem 2-5 obtains The temperature information of the primary sensing unit 1 and the secondary processing unit 2 is input into the collector 2-3 through an optical fiber; Analyze the data information of the merging unit 2-6 to obtain the working status information of the optical current sensor 1-1, the status information of the LED light source 2-1, the primary optical fiber temperature sensor 1-2 and the secondary optical fiber temperature sensor 2-4. The obtained temperature information is recorded at regular time intervals.

In this embodiment, the primary sensing unit 1, the secondary processing unit 2 and the reliability data recording unit 3 are all connected by optical fibers for signal connection, and all external interfaces are optical interfaces, which improves the system's ability to resist electromagnetic interference.

Embodiment 2: The present embodiment will be described below with reference to FIG. 1 . This embodiment will further describe Embodiment 1. The primary optical fiber temperature sensor 1-2 is closely attached to the side wall of the optical current sensor 1-1.

In this embodiment, the primary optical fiber temperature sensor 1-2 is closely attached to the optical current sensor 1-1, so as to accurately detect the ambient temperature where the optical current sensor 1-1 is located.

Specific embodiment three: the present embodiment is described below in conjunction with Fig. 1, and this embodiment is further described to embodiment one, and primary sensing unit 1 comprises multiple sets of identical optical current sensors 1-1 and primary optical fiber temperature sensors 1-2, divided into Each optical current sensor 1-1 receives a beam of light emitted by the LED light source 2-1, and the optical signal passing through each optical current sensor 1-1 is connected to the collector 2-3 through an optical fiber, and each primary optical fiber temperature sensor 1 -2 are connected to temperature modem 2-5 through optical fiber.

Embodiment 4: The present embodiment will be described below in conjunction with FIG. 1. This embodiment will further describe Embodiment 1. The reliability data recording unit 3 analyzes the data information of the merging unit 2-6 to obtain the optical current sensor 1-1. The specific process of the working state information and the state information of the LED light source 2-1 is as follows:

Assume that the optical power emitted by the LED light source 2-1 is P ₀ , the fluctuation coefficient is β, the splitting ratio of the optical fiber beam splitter 2-2 is K ₁ :K ₂ , and the optical path loss coefficient of the optical current sensor 1-1 is α;

There are two optical signals received by the collector 2-3: one from the output P ₁ of the optical current sensor 1-1, and one from the output P ₂ of the optical fiber splitter 2-2 directly connected to the collector 2-3;

The output P ₁ from the optical current sensor 1-1 is expressed as:

P ₁ ＝αK ₁ βP ₀ [1+sin(2θ)] (1)

Wherein, θ is the Faraday rotation angle corresponding to the measured current i (t) of the primary conductor 4;

Before the analog-to-digital conversion of the collector 2-3, the output P ₁ of the optical current sensor 1-1 is decomposed into two signals: one is the AC signal containing the measured current i(t) of the primary conductor 4, and the other is the optical current sensor 1 The DC bias signal of -1, the DC bias signal of the optical current sensor 1-1 is expressed as:

P _1dc = αK ₁ βP ₀ (2)

The output P ₂ from the optical fiber splitter 2-2 directly connected to the collector 2-3 is expressed as:

P ₂ =K ₂ βP ₀ (3)

Assuming that at the initial moment of monitoring, the DC bias output of the optical current sensor 1-1 and the output of the fiber beam splitter 2-2 are represented by P ₁₀ and P ₂₀ respectively:

P ₁₀ =α ₀ K ₁ β ₀ P ₀ (4)

P ₂₀ = K ₂ β ₀ P ₀ (5);

Among them, α ₀ represents the optical path loss coefficient at the initial monitoring moment, and β ₀ represents the fluctuation coefficient at the initial monitoring moment;

During the monitoring process, the DC bias output of the optical current sensor 1-1 and the output of the fiber beam splitter 2-2 are represented by P ₁₁ and P ₂₁ respectively:

P ₁₁ =α ₁ K ₁ β ₁ P ₀ (6)

P ₂₁ =K ₂ β ₂ P ₀ (7);

Among them, α ₁ represents the optical path loss coefficient in the monitoring process, and β ₁ represents the fluctuation coefficient in the monitoring process;

The variation of the insertion loss is selected as the criterion for the failure of the optical current sensor, then the insertion loss of the output optical path of the optical current sensor 1-1, including the variation of the fluctuation of the LED light source 2-1, △A _1IL is expressed as:

${\mathrm{<span\; class="notranslate">\; \&Delta;A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; I</span>}\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; g</span>}\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; g</span>}\frac{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; g</span>}\frac{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

The insertion loss of the output optical path of the optical fiber splitter 2-2, that is, the variation △A _2IL of the fluctuation of the LED light source 2-1 is expressed as:

${\mathrm{<span\; class="notranslate">\; \&Delta;A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; I</span>}\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; g</span>}\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; one</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 20</span>}}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; g</span>}\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; g</span>}\frac{{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

From formula (8) and formula (9), the insertion loss of optical current sensor 1-1 is obtained, and the change amount △A _αIL excluding the fluctuation of LED light source 2-1 is expressed as:

${\mathrm{<span\; class="notranslate">\; \&Delta;A</span>}}_{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}\mathrm{<span\; class="notranslate">\; I</span>}\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; g</span>}\frac{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&Delta;A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; I</span>}\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; I</span>}\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

Namely: obtain the variation of the fluctuation of the LED light source 2-1 and the variation of the fluctuation of the LED light source 2-1 eliminated by the insertion loss of the optical current sensor 1-1;

The fluctuation amount of the LED light source 2-1 is the working state information of the LED light source 2-1;

The insertion loss of the optical current sensor 1-1 eliminates the variation of the fluctuation of the LED light source 2-1, which is the working state information of the optical current sensor 1-1.

Claims (4)

1. a kind of reliability monitoring system of optical current mutual inductor is it is characterised in that include sensing unit (1), secondary Processing unit (2) and reliability data recording unit (3), sensing unit (1), after-treatment unit (2) and reliability number All connected with optical fiber according between recording unit (3)；

One time sensing unit (1) includes optical current sensor (1-1) and a fibre optic temperature sensor (1-2), after-treatment Unit (2) include LED light source (2-1), fiber optic splitter (2-2), harvester (2-3), secondary fibre optic temperature sensor (2-4), Temperature modulation demodulator (2-5) and combining unit (2-6)；

The light that LED light source (2-1) sends is divided into two-beam through fiber optic splitter (2-2), and a road light inputs optics by optical fiber The incidence end of current sensor (1-1), another road optical transport to harvester (2-3)；Light through optical current sensor (1-1) Signal passes through intelligent acess harvester (2-3), a fibre optic temperature sensor (1-2) and secondary fibre optic temperature sensor (2-4) All by intelligent acess temperature modulation demodulator (2-5), a sensing unit (1) that temperature modulation demodulator (2-5) obtains and The temperature information of after-treatment unit (2) inputs harvester (2-3) by optical fiber；Harvester (2-3) is in the way of serial communication It is connected with combining unit (2-6) by optical fiber, reliability data recording unit (3) is entered to the data message of combining unit (2-6) Row parsing, obtains the work state information of optical current sensor (1-1), the status information of LED light source (2-1), an optical fiber The temperature information that temperature sensor (1-2) and secondary fibre optic temperature sensor (2-4) record, and logarithm at regular intervals According to being recorded.

2. a kind of reliability monitoring system of optical current mutual inductor according to claim 1 is it is characterised in that once light Fine temperature sensor (1-2) is closely affixed on the side wall of optical current sensor (1-1).

3. a kind of reliability monitoring system of optical current mutual inductor according to claim 1 is it is characterised in that once pass Sense unit (1) includes multigroup identical optical current sensor (1-1) and a fibre optic temperature sensor (1-2), a point optics Current sensor (1-1) all receives the light beam that LED light source (2-1) sends, through the light of each optical current sensor (1-1) Signal all by intelligent acess harvester (2-3), all adjusted by intelligent acess temperature by each fibre optic temperature sensor (1-2) Modulator-demodulator (2-5).

4. a kind of reliability monitoring system of optical current mutual inductor according to claim 1 is it is characterised in that reliability Data record unit (3) parses to the data message of combining unit (2-6), obtains the work of optical current sensor (1-1) The detailed process making the status information of status information and LED light source (2-1) is:

If the luminous power that LED light source (2-1) sends is p₀, coefficient of variation is β, and the splitting ratio of fiber optic splitter (2-2) is k₁:k₂, Optical current sensor (1-1) optical path loss factor alpha；

The optical signal that harvester (2-3) receives is two-way: comes and exports p from optical current sensor (1-1)₁, come certainly Fiber optic splitter (2-2) is directly connected to the output p of harvester (2-3)₂；

Export p from optical current sensor (1-1)₁, it is expressed as:

p₁=α k₁βp₀[1+sin(2θ)] (1)

Wherein, θ is the Faraday rotation angle corresponding to tested electric current i (t) of Primary Conductor (4)；

Before harvester (2-3) analog digital conversion, optical current sensor (1-1) exports p₁It is broken down into two paths of signals: a road is Comprise the AC signal of tested electric current i (t) of Primary Conductor (4), a road is the direct current biasing letter of optical current sensor (1-1) Number, the DC bias signal of optical current sensor (1-1) is expressed as:

p_1dc=α k₁βp₀(2)

It is directly connected to the output p of harvester (2-3) from fiber optic splitter (2-2)₂, it is expressed as:

p₂=k₂βp₀(3)

It is located at supervision initial time, the direct current biasing output of optical current sensor (1-1) and fiber optic splitter (2-2) output point Do not use p₁₀And p₂₀Represent:

p₁₀=α₀k₁β₀p₀(4)

p₂₀=k₂β₀p₀(5)；

Wherein, α₀Represent the optical path loss coefficient in monitoring initial time, β₀Represent the coefficient of variation in monitoring initial time；

During monitoring, the direct current biasing output of optical current sensor (1-1) and fiber optic splitter (2-2) output are used respectively p₁₁And p₂₁Represent:

p₁₁=α₁k₁β₁p₀(6)

p₂₁=k₂β₂p₀(7)；

Wherein, α₁Represent the optical path loss coefficient during monitoring, β₁Represent the coefficient of variation during prison；

Select the criterion that the variable quantity of insertion loss lost efficacy as optical current sensor, then optical current sensor (1-1) is defeated Go out light path insertion loss, including the variable quantity δ a of the fluctuation of LED light source (2-1)_1ilIt is expressed as:

${\mathrm{\&delta;a}}_{1il}=-10log\frac{p_{11}}{p_{10}}=-10log\frac{{\mathrm{\&alpha;}}_1{k}_1{\mathrm{\&beta;}}_1{p}_0}{{\mathrm{\&alpha;}}_0{k}_1{\mathrm{\&beta;}}_0{p}_0}=-10log\frac{{\mathrm{\&alpha;}}_1{\mathrm{\&beta;}}_1}{{\mathrm{\&alpha;}}_0{\mathrm{\&beta;}}_0}---\left(8\right)$

Fiber optic splitter (2-2) output light path insertion loss, the variable quantity δ a that is, LED light source (2-1) fluctuates_2ilIt is expressed as:

${\mathrm{\&delta;a}}_{2il}=-10log\frac{p_{21}}{p_{20}}=-10log\frac{k_2{\mathrm{\&beta;}}_1{p}_0}{k_2{\mathrm{\&beta;}}_0{p}_0}=-10log\frac{{\mathrm{\&beta;}}_1}{{\mathrm{\&beta;}}_0}---\left(9\right)$

By formula (8) and formula (9), obtain optical current sensor (1-1) insertion loss, reject the change of the fluctuation of LED light source (2-1) Change amount δ a_αilIt is expressed as:

${\mathrm{\&delta;a}}_{\mathrm{\&alpha;}il}=-10log\frac{{\mathrm{\&alpha;}}_1}{{\mathrm{\&alpha;}}_0}={\mathrm{\&delta;a}}_{1il}-{\mathrm{\&delta;a}}_{2il}---\left(10\right)$

That is: variable quantity and optical current sensor (1-1) insertion loss rejecting LED light source that LED light source (2-1) fluctuates are obtained (2-1) variable quantity of fluctuation；

The variable quantity that LED light source (2-1) fluctuates is the work state information of LED light source (2-1)；

The variable quantity that optical current sensor (1-1) insertion loss rejects the fluctuation of LED light source (2-1) is optical current sensor (1-1) work state information.