阅读说明：本技术 一种低湿度敏感性的光纤电流互感器 (Low-humidity sensitive optical fiber current transformer ) 是由 向强 冯喆 杨怿 吴衍记 徐磊 于 2018-06-26 设计创作，主要内容包括：本发明公开了一种低湿度敏感性的光纤电流互感器,它包括采集单元、传感环圈和光纤光缆,采集单元与传感环圈通过光纤光缆连接。本发明的优点是,通过在采集单元结构设计中采用密封设计,下罩采用整体化设计,减少泄漏点,在下罩和上盖板中使用密封圈,并且使用胶对内部不规则的光电接口进行密封,使用密封胶带对光电接口外部进行密封,有效提高了采集单元的密封性能；通过采用多项措施整体增强光纤电流互感器的密封特性,有效抑制了互感器的湿度敏感性,简单有效,能实现光纤电流互感器长期可靠工程应用。(The invention discloses a low-humidity sensitive optical fiber current transformer which comprises an acquisition unit, a sensing ring and an optical fiber cable, wherein the acquisition unit is connected with the sensing ring through the optical fiber cable. The invention has the advantages that the sealing design is adopted in the structural design of the acquisition unit, the lower cover adopts the integrated design, the leakage points are reduced, the sealing rings are used in the lower cover and the upper cover plate, the internal irregular photoelectric interface is sealed by using glue, the external part of the photoelectric interface is sealed by using the sealing adhesive tape, and the sealing performance of the acquisition unit is effectively improved; the sealing characteristic of the optical fiber current transformer is integrally enhanced by adopting a plurality of measures, the humidity sensitivity of the transformer is effectively inhibited, the method is simple and effective, and the long-term reliable engineering application of the optical fiber current transformer can be realized.)

1. A low moisture sensitive fiber optic current transformer, comprising: the optical fiber cable sensor comprises an acquisition unit (1), a sensing ring (3) and an optical fiber cable (2), wherein the acquisition unit (1) is connected with the sensing ring (3) through the optical fiber cable (2).

2. The low moisture sensitivity fiber optic current transformer of claim 1, wherein: the collecting unit (1) comprises an integrated lower cover (4), a sealing ring (7), an upper cover plate (9), a photoelectric interface (5) and an internal photoelectric module (6), wherein the middle of the integrated lower cover (4) and the upper cover plate (9) is sealed through the sealing ring (7), the outer side of the sealing ring (7) is fixed through a screw (8), the internal photoelectric module (6) is fixed in a mode of being installed inside the collecting unit (1), and the photoelectric interface (5) penetrates through the outer wall (10) of the collecting unit and is fixed on the outer wall.

3. The low moisture sensitivity fiber optic current transformer of claim 2, wherein: and sealing silicone grease is uniformly coated around the sealing ring (7) to enhance the sealing property.

4. The low moisture sensitivity fiber optic current transformer of claim 2, wherein: the photoelectric interface (5) is uniformly coated at the gap of the photoelectric interface (5) by using a sealant (12) to resist the entry of moisture, and the thickness is not less than 2 mm.

5. The low moisture sensitivity fiber optic current transformer of claim 1, wherein: sensing ring circle (3) including base (15), sealing washer (7), upper cover (14), optical fiber cable interface (17), several parts of inside sensing module (16), sensing ring circle base (15) adopt the wholeization preparation, seal through sealing washer (7) in the middle of base (15) and upper cover (14), sealing washer (7) outside is fixed through screw (8), inside sensing module (16) unable adjustment base (15) are inside, optical fiber cable interface (17) embedding is on the outer wall of base (15) and bonds through sealed glue (12), optical fiber cable (2) pass optical fiber cable interface (17) and are connected with inside sensing module (16).

6. The low moisture sensitivity fiber optic current transformer of claim 1, wherein: optical fiber cable (2) adopt high-strength multilayer seal structure, the inlayer is special type optic fibre (18), special type optic fibre (18) periphery is optic fibre cream (19), have half mobility, can effectively protect special type optic fibre (18) not erodeed by steam, optic fibre cream (19) are sealed in fiber casing (20), fiber casing (20) are outer aramid fiber silk (21), play the effect of protection and reinforcing tensile force, aramid fiber silk (21) outside is optic fibre sheath (22), bellows (23) are the outermost, place the optical cable inside bellows (23), can effectively protect the optical cable to resist external pressure, tensile force, have higher intensity.

7. The low moisture sensitivity fiber optic current transformer of claim 6, wherein: the diameter of the special optical fiber (18) is about 250 μm, and about 170 μm or other thinner optical fibers can be adopted.

8. The low moisture sensitivity fiber optic current transformer of claim 6, wherein: the diameter of the optical fiber sleeve (20) is about 900 mu m to 1.5 mm.

Technical Field

The invention belongs to, and particularly relates to. The invention relates to an optical fiber current transformer with low humidity sensitivity, and belongs to the technical field of power equipment.

Background

With the development of smart power grids towards high voltage, ultrahigh voltage and extra-high voltage, the voltage class of smart substations is higher and higher, substations of 110kV and 220kV are very common, and substations with voltage class higher than 1000kV are also built. Meanwhile, the smart grid has higher and higher requirements on aspects of informatization, automation, interactivity, quick response and the like, and the traditional current transformer gradually has exposed principle defects and cannot well adapt to the development requirements of the power grid. The optical fiber current transformer serving as a passive electronic current transformer has the outstanding advantages in the aspects of adaptation to high-voltage application, informatization and quick response, such as relatively simple insulation, no ferromagnetic saturation, good transient characteristic, direct adoption of digital quantity output and the like, and is the development direction of future current transformers.

The basic principle of the optical fiber current transformer is the magneto-optical faraday effect, that is, an optical fiber is wound around a live conductor, and polarized light transmitted in the optical fiber is deflected under the influence of a magnetic field generated by current, wherein the deflection angle theta is related to the number of turns N of the wound optical fiber, the Verdet constant V of the optical fiber and the conductor current I, and the specific relationship is 2 VNI.

The optical fiber current transformer has a severe operating environment and is often in a high-temperature high-humidity condition, a power system has high requirements on the operating stability and reliability of the transformer, the operating life of primary equipment is generally required to be not less than 40 years, the operating life of secondary equipment is generally required to be not less than 20 years, the equipment is required to be highly reliable in the operating process, and the transformer fault can cause the power failure of a transformer substation, so that great economic and social negative effects are brought. If the performance of the current transformer is changed due to the influence of humidity or the service life of the current transformer is influenced in a high-temperature and high-humidity environment for a long time, the reliability and the stability of the current transformer are seriously influenced, and therefore, the sensitivity of the current transformer to the humidity is reduced by the method.

The patent "a high-precision high-reliability all-fiber current transformer" (application number: CN201410125918.9) discloses a high-reliability transformer, which adopts a design method of redundant active optical devices and a scheme of dual-output light subtraction processing to improve the stability and precision of the transformer, but does not propose how to reduce the humidity sensitivity. The patent of a sensing head of an all-fiber current transformer (application number: 201320127370.2) discloses a preparation method of the sensing head, which can effectively eliminate the negative effects of linear birefringence and the like of an optical fiber sensing part, but the specific method for reducing humidity sensitivity of the sensing head is not clear, and the reliability hidden danger exists in the long-term use process.

Disclosure of Invention

The invention aims to provide a low-humidity-sensitivity optical fiber current transformer, which inhibits the humidity sensitivity of the optical fiber current transformer and improves the stability and reliability of the transformer in operation under a high-humidity environment by enhancing the sealing performance of each part of an acquisition unit, a sensing ring and an optical fiber cable.

The invention is realized in such a way that the low-humidity-sensitivity optical fiber current transformer comprises an acquisition unit, a sensing ring and an optical fiber cable, wherein the acquisition unit is connected with the sensing ring through the optical fiber cable.

The collecting unit comprises an integrated lower cover, a sealing ring, an upper cover plate, a photoelectric interface and an internal photoelectric module, wherein the middle of the integrated lower cover and the upper cover plate is sealed through the sealing ring, the outer side of the sealing ring is fixed through a screw, the internal photoelectric module is fixed in a mode of mounting from the inside of the collecting unit, and the photoelectric interface penetrates through the outer wall of the collecting unit and is fixed on the outer wall of the collecting unit.

And sealing silicone grease is uniformly coated around the sealing ring to enhance the sealing property.

The photoelectric interface is uniformly coated with sealant in gaps to resist moisture, and the thickness of the photoelectric interface is not less than 2 mm.

And after the optical fibers and the electric wires are connected, performing secondary sealing at the outer interface by using a sealing adhesive tape.

The sensing ring comprises a base, a sealing ring, an upper cover, an optical fiber cable interface and an internal sensing module, wherein the base of the sensing ring is integrally manufactured, the middle of the base and the upper cover is sealed through the sealing ring, the outer side of the sealing ring is fixed through a screw, the internal sensing module is fixed inside the base, the optical fiber cable interface is embedded into the outer wall surface of the base and is bonded through sealing glue, and an optical fiber cable penetrates through the optical fiber cable interface and is connected with the internal sensing module.

The optical fiber cable adopts a high-strength multilayer sealing structure, the innermost layer is the special optical fiber, the periphery of the special optical fiber is the optical fiber paste, the semi-fluidity is achieved, the special optical fiber can be effectively protected from being corroded by water vapor, the optical fiber paste is sealed in the optical fiber sleeve, the aramid fiber wire is arranged outside the optical fiber sleeve and plays a role in protecting and enhancing the tensile force, the optical fiber sleeve is arranged outside the aramid fiber wire, the corrugated pipe is arranged at the outermost layer, the optical cable is arranged inside the corrugated pipe, the external pressure and the external tensile force can be effectively protected, and the high-strength optical fiber cable.

The diameter of the special optical fiber is about 250 μm, and an optical fiber with the diameter of about 170 μm or other thinner optical fibers can be adopted.

The diameter of the optical fiber sleeve is about 900 mu m to 1.5 mm.

The invention has the advantages that 1) the invention adopts the sealing design in the structural design of the acquisition unit, the lower cover adopts the integrated design, the leakage points are reduced, the sealing rings are used in the lower cover and the upper cover plate, the internal irregular photoelectric interface is sealed by using glue, the external part of the photoelectric interface is sealed by using the sealing adhesive tape, and the sealing performance of the acquisition unit is effectively improved; 2) according to the invention, the sealing design is adopted in the structural design of the sensing ring, so that leakage points are reduced, the sealing rings are used in the base and the upper cover, and the irregular optical fiber cable interface is sealed by using glue, so that the sealing performance of the sensing ring is effectively improved; 3) according to the invention, by using the optical fiber cable with a multilayer protection structure, the internal functional optical fiber is effectively protected from being corroded by water vapor, and the optical fiber cable has higher capacity of resisting external pressure and tension; 4) the invention integrally enhances the sealing characteristic of the optical fiber current transformer by adopting a plurality of measures, effectively inhibits the humidity sensitivity of the transformer, is simple and effective, and can realize the long-term reliable engineering application of the optical fiber current transformer.

Drawings

FIG. 1 is a schematic diagram of a low moisture sensitive fiber optic current transformer in its entirety;

FIG. 2 is a schematic view of an acquisition unit;

FIG. 3 is a schematic view of an optoelectronic interface seal;

FIG. 4 is a schematic cross-sectional view of a sensing loop;

fig. 5 is a schematic diagram of a typical structure of an optical fiber cable.

In the figure: the optical fiber cable comprises an acquisition unit 1, an optical fiber cable 2, a sensing ring 3, an integrated lower cover 4, a photoelectric interface 5, an internal photoelectric module 6, a sealing ring 7, a screw 8, an upper cover plate 9, an acquisition unit outer wall 10, optical fibers and electric wires 11, a sealant 12, a sealing adhesive tape 13, an upper cover 14, a base 15, an internal sensing module 16, an optical fiber cable interface 17, a special optical fiber 18, optical fiber paste 19, an optical fiber sleeve 20, an aramid fiber wire 21, an optical fiber sheath 22 and a corrugated pipe 23.

Detailed Description

The invention is described in detail below with reference to the following figures and specific embodiments:

the whole mutual inductor comprises an acquisition unit, a sensing ring and an optical fiber cable, and the three parts are respectively subjected to reinforced sealing treatment, so that the resistance of the mutual inductor to humidity is improved. These three parts will be described one by one.

The acquisition unit comprises an integrated lower cover, a sealing ring, an upper cover plate, a photoelectric interface and an internal photoelectric module. The lower cover is made integrally, the internal photoelectric module is fixed in an internal installation mode from the acquisition unit, through holes cannot be used, and the internal photoelectric module cannot be fixed by screws from the outside, because the moisture entering channel can be increased, and the whole acquisition unit is not provided with a part which is possibly filled with moisture such as a seam and the like in the internal part except the upper cover and the photoelectric interface. The middle of the lower cover and the upper cover plate is sealed through a sealing ring, and the outer side of the sealing ring is fixed through a screw. The number of opto-electronic interfaces may vary from product design to product design and typically includes a power line interface, a fiber optic cable interface connected to the merging unit, and a fiber optic cable interface connected to the sensing loop. The opto-electrical interface is non-uniform in shape and resists moisture ingress by being internally sealed with glue. Because the optical fiber interface is communicated internally, in order to ensure the sufficient sealing performance and simultaneously consider the convenience of engineering field operation, the optical fiber is sealed secondarily at the outer interface by using a sealing adhesive tape after being connected. The internal photoelectric module is a secondary side power supply and resolving part of the optical fiber current transformer and comprises a power supply, a circuit, an optical device and the like, and the collection unit is sealed to ensure that the internal photoelectric module is not influenced by moisture.

The sensing ring comprises a base, a sealing ring, an upper cover, an optical fiber cable interface and an internal sensing module. The sensing ring base is also manufactured integrally, a through threaded hole cannot be designed, and no seam or other parts which can flow moisture into the sensing ring base except the upper cover and the optical fiber cable interface exists inside the sensing ring base. The middle of the base and the upper cover is sealed through a sealing ring, and the outer side of the sealing ring is fixed through a screw. The optical fiber cable interface is sealed by internal glue coating, so that external moisture is prevented from flowing into the ring. The inner sensing module is a core part of the sensing ring sensitive to current, and the sealing of the sensing ring is to ensure that the inner sensing module is not affected by moisture.

The optical fiber cable between the acquisition unit and the sensing ring adopts a high-strength sealing structure design, and meanwhile, a protective sleeve is added to the outside for protection, so that the corrosion of moisture can be effectively resisted, and the optical fiber cable has higher tensile and compressive properties. The design of the optical cable is various, and a typical structure is provided, but the optical cable is not limited to the structure in practice. The innermost layer is a special optical fiber, generally an optical fiber with a polarization maintaining effect, and the diameter of the optical fiber is generally about 250 μm (about 170 μm or other thinner optical fibers can also be adopted). The periphery of the optical fiber is provided with the optical fiber paste which can effectively protect the optical fiber from being corroded by water vapor, the optical fiber paste is sealed in the optical fiber sleeve, and the diameter of the optical fiber sleeve is generally about 900 micrometers to 1.5 mm. The aramid fiber yarn is arranged outside the optical fiber sleeve, so that the functions of protecting and enhancing the tensile force are achieved. The aramid fiber is covered with an optical fiber sheath, the diameter of the aramid fiber is generally about 3mm to 5mm, and the aramid fiber has certain waterproof and tensile functions. The corrugated pipe is arranged at the outermost part, the optical cable is arranged in the corrugated pipe, the optical cable can be effectively protected against external pressure and tensile force, and the corrugated pipe has high strength.

As shown in fig. 1 to 5, a low-humidity-sensitivity fiber optic current transformer includes a sealed acquisition unit (as shown in fig. 2 and 3), a sealed sensing loop (as shown in fig. 4) and a sealed fiber optic cable (as shown in fig. 5).

Fig. 1 is an overall schematic diagram of a low-humidity sensitive optical fiber current transformer, which integrally includes three parts, namely an acquisition unit 1, a sensing loop 3 and an optical fiber cable 2, because the optical fiber current transformer is often located in a high-temperature and high-humidity environment, in order to avoid the influence of humidity on the internal optics and electronics of the transformer, the transformer needs to be effectively isolated from the outside. In the invention, the three parts are respectively subjected to reinforced sealing treatment, so that the resistance of the transformer to humidity is improved. These three parts will be described one by one.

As shown in fig. 2, the collection unit 1 includes an integrated lower cover 4, a sealing ring 7, an upper cover plate 9, an optoelectronic interface 5, and an internal optoelectronic module 6. When the integrated lower cover 4 is manufactured, internal holes and gaps need to be reduced as much as possible, an integrated manufacturing mode is adopted, and particularly, a mounting plate splicing mode cannot be adopted. The internal photovoltaic module 6 is fixed in a manner that it is internally mounted from the acquisition unit 1, it is not possible to use through holes and it is not possible to fix it externally with screws, since this increases the passage of the moisture entering. The entire collection unit 1 is free of seams, openings, etc. inside the unit except for the upper cover plate 9 and the photoelectric interface 5, where moisture may flow in. The middle of the integrated lower cover 4 and the upper cover plate 9 is sealed by a sealing ring 7, and the outer side of the sealing ring 7 is fixed by a screw 8. The sealing ring 7 is to select a product which is good in quality and matched with the structure of the acquisition unit 1, the number of the screws 8 is moderate, the distance between the screws is generally designed within the range of 5 cm-15 cm, one screw is generally designed at each of four corners, and when the screws are screwed, the sealing ring 7 is ensured to be evenly and tightly extruded between the integrated lower cover 4 and the upper cover plate 9. Sealing silicone grease is evenly coated around the sealing ring 7 to enhance the sealing performance. The opto-electronic interface 5 is not a single interface but a collective term for a set of optical and electrical interfaces. The number of opto-electronic interfaces 5 may vary from product design to product design and typically includes a power line interface, a fiber optic cable interface connected to the merging unit and a fiber optic cable interface connected to the sensing loop. The shapes of the photoelectric interfaces 5 are not uniform and are often irregular, and the sealing of the photoelectric interfaces 5 is a difficult point and a key point for sealing the acquisition unit 1 and needs to be solved by an internal and external double sealing mode. The sealing schematic diagram of the optical-electrical interface 5 is shown in fig. 3, and the sealant 12 is uniformly applied to the inside of the gaps of the optical-electrical interface 5 to resist moisture from entering, and the thickness is not less than 2 mm. There are many kinds of the sealant 12, but in order to ensure good sealing performance, a sealant with good temperature performance, which can reliably work at-40 ℃ to +80 ℃ and has good sealing performance is selected. Because the photoelectric interface 5 is communicated internally, in order to ensure sufficient sealing performance and simultaneously consider the convenience of engineering field operation, the optical fiber and the electric wire 11 are connected and then sealed secondarily at the outer interface by the sealing adhesive tape 13. The internal photoelectric module 6 is a secondary side power supply and resolving part of the optical fiber current transformer and comprises a power supply, a circuit, an optical device and the like, and the sealing of the acquisition unit 1 is to ensure that the internal photoelectric module 6 is not influenced by moisture.

Fig. 4 shows a schematic cross-sectional view of the sensing loop 3, where the sensing loop 3 includes a base 15, a sealing ring 7, an upper cover 14, an optical fiber cable interface 17, and an internal sensing module 16. The sensor ring base 15 is also made in an integrated manner, and should not be designed with an open threaded hole, and there are no other unnecessary gaps, except for the upper cover 14 and the optical fiber cable interface 17, where there are no seams, openings, etc. inside which moisture may flow. The middle of the base 15 and the upper cover 14 is sealed by a sealing ring 7, and the outer side of the sealing ring 7 is fixed by a screw 8. The sealing ring 7 is a product which has good quality and is matched with the structure of the sensing ring 3, the number of the screws 8 is moderate, the distance between the screws is generally designed within the range of 5 cm-15 cm, one screw is generally designed at each of four corners, and when the screws are screwed, the sealing ring 7 is ensured to be evenly and tightly extruded between the base 15 and the upper cover 14. Sealing silicone grease is evenly coated around the sealing ring 7 to enhance the sealing performance. The optical fiber cable interface 17 is sealed through internal gluing, the sealant 12 is uniformly coated around an outlet inside the optical fiber cable 2, the minimum thickness is not less than 2mm, and external moisture is prevented from flowing into the ring. There are many kinds of the sealant 12, but in order to ensure good sealing performance, a sealant with good temperature performance, which can reliably work at-40 ℃ to +80 ℃ and has good sealing performance is selected. The inner sensor module 16 is a core part of the sensor ring 3 sensitive to current, and the sealing of the sensor ring 3 is to ensure that the inner sensor module 16 is not affected by moisture.

The optical fiber cable 2 between the acquisition unit 1 and the sensing ring 3 adopts a high-strength multilayer sealing structure design, and meanwhile, a protective sleeve is added to the outside for protection, so that the corrosion of moisture is effectively resisted, and the optical fiber cable has higher tensile and compressive properties. The design of the optical cable is various, and a typical structure is provided, but the optical cable is not limited to the structure in practice. The innermost layer is a special optical fiber 18, which is generally an optical fiber with a polarization maintaining effect, and may be a geometric effect type, such as an elliptical core optical fiber, and may also be a stress induction type, such as a panda type optical fiber, a bow tie type optical fiber, and the like. The diameter of the specialty fiber 18 is typically about 250 μm, and it is also possible to use about 170 μm or other thinner fibers. The periphery of the special optical fiber 18 is provided with the optical fiber paste 19 which has semi-fluidity and can effectively protect the special optical fiber 18 from being corroded by water vapor, the optical fiber paste 19 is sealed in the optical fiber sleeve 20, and the diameter of the optical fiber sleeve 20 is about 900 micrometers to 1.5mm generally. The aramid fiber filaments 21 are arranged outside the optical fiber sleeve 20, and play a role in protecting and enhancing tension. The outside of the aramid fiber filament 21 is provided with an optical fiber sheath 22, the diameter is generally about 3mm to 5mm, a thicker sheath can be adopted, certain waterproof and tensile effects are achieved, the short-term tensile force of the optical fiber sheath 22 is generally not lower than 120N, and the long-term tensile force is generally not lower than 60N; the short-term flattening force is generally not less than 400N, and the long-term flattening force is generally not less than 80N. The corrugated pipe 23 is arranged at the outermost part, and the optical cable is arranged in the corrugated pipe 23, so that the optical cable can be effectively protected against external pressure and tensile force, and has high strength. The short-term tensile force of the corrugated pipe 23 is generally not less than 260N, and the long-term tensile force is generally not less than 120N; the short-term flattening force is generally not less than 600N, and the long-term flattening force is generally not less than 130N.