CN101340045B - Method and apparatus capable of realizing safe hot plug of secondary current loop of transforming plant - Google Patents

Abstract

A method and device capable of realizing safe hot swapping of a secondary current loop of a substation belong to the field of safety devices. Including the access terminal of the secondary circuit current transformer and the current transformer to be connected, a plug-in reed set with double elastic contacts is set between the connection ends of the current transformer access terminal; at the same time, a The bidirectional diode group is also provided with an insertion board with double-sided conductive layers and the two conductive layers are insulated from each other. The conductive layers on both sides of the insertion board are respectively electrically connected to the two ends of the primary coil of the current transformer to be connected. It uses mechanical and electronic dual technical means to ensure that the commissioning/exit of the secondary circuit is under the most simple and reliable technical protection, and realizes the "hot swap" of the secondary current circuit of the substation electric meter, which greatly simplifies the operation The cumbersome process of maintenance, replacement and test debugging of medium and medium measuring equipment improves the reliability of equipment operation. The utility model can be widely used in the electric measurement or monitoring field of the power transformation and distribution system.

Description

Method and device capable of realizing safe hot-swapping of substation secondary current loop

technical field

The invention belongs to the field of safety devices, in particular to a safety connection device for a secondary current circuit of a substation electric measuring meter.

Background technique

The secondary current loop must be sampled in the process of substation electrical monitoring and monitoring.

In the past, a large number of secondary instruments in substations used a panel structure, but now more and more microcomputer measurement/digital processing technologies are used.

But no matter what, the measuring equipment and the secondary voltage and current circuits all have "interfaces" connected by wires. Due to the characteristics of the secondary current of the current transformer (CT), the secondary circuit must not be open during operation. The high voltage generated by the open circuit of the secondary circuit will pose a threat to personal safety, and will also cause the primary CT to heat up and cause hidden dangers to the primary equipment.

For this reason, at present, the secondary circuit of the substation must ensure the reliability of the circuit connection during operation. The specific requirements in the "Power System Safety Operation Regulations" are usually reflected as follows: when exiting the secondary measurement equipment in operation, first need to Short-circuit its current circuit and open the voltage circuit, and then remove its connecting wires, etc., the whole process is very troublesome and complicated/strict, and a little carelessness may easily cause operation accidents or cause equipment and personal injury. Moreover, in actual work, it is not uncommon for equipment accidents and personal injuries to occur due to the operator's negligence of this safety regulation or the wrong operation sequence, and it may even develop into a major equipment accident or failure of the entire power system.

In the actual field work, there is an urgent need for a simple connection method to complete the input and exit of the secondary measurement equipment. An open circuit in the secondary circuit has occurred.

The announcement date is June 22, 2005, and the announcement number is a Chinese patent of CN 2705952Y, which discloses a "hot plug buffer circuit", which consists of a power supply slow start switch circuit (1), a power supply slow start circuit (2), The bus buffer switch circuit (3) is composed of the bus buffer switch circuit (4) and the pin family (5); the power buffer switch circuit (1) is connected to the pin family (5), and the bus buffer switch circuit (3) and the pin family family (5), the power supply buffer switch circuit (1) is connected with the power supply slow start circuit (2), the power supply slow start circuit (2) is also connected with the bus buffer switch circuit (3), the bus buffer circuit (4), and the bus buffer The switch circuit (3) is connected with the bus buffer circuit (4). The beneficial effect of the utility model is that, due to the adoption of the integrated circuit, the stability is enhanced, and the board card can be replaced at will during the continuous and reliable operation of the equipment without affecting the system operation.

In the field of computer and communication systems, hot-plugging or Hot Swap is live plugging, and the hot-plugging function allows users to remove and replace damaged hard drives and power supplies without shutting down the system or cutting off the power supply. or boards and other computer hardware components, thereby improving the system's ability to recover from disasters in a timely manner, scalability and flexibility, etc. For example, some disk mirroring systems for high-end applications can provide disk hot-swappable functions.

Hot plugging first appeared in the server field of PCs, and it was proposed to improve the usability of servers. Generally, there are USB interfaces in our usual computers, and this interface can realize hot plugging. If there is no hot-swappable function, even if the disk damage will not cause data loss, the user still needs to temporarily shut down the system in order to be able to replace the hard disk. With the hot-swappable technology, it can be directly removed by simply opening the connection switch or turning the handle. hard drive while the system continues to operate normally without interruption.

In the fields of PCs and communication systems, the design of hot-swappable circuits is widely used. However, as far as the applicant knows, in the field of power transformation and distribution and/or power transmission and transformation industries, for the secondary current loop of the electric meter in the substation, Still do not have the technical scheme that has similar function or can reach same technical effect to be available for selection or implementation.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method and device capable of realizing safe hot swapping of the secondary current loop of the substation. It uses mechanical and electronic dual technical means to ensure that the "commissioning" and "exit" of the secondary circuit are under the most simple and reliable technical protection, and realizes the "hot swapping" of the secondary current circuit of the substation electric meter, greatly It simplifies the cumbersome process of maintenance, replacement and test debugging of measuring equipment during operation, and improves the reliability of equipment operation.

The technical solution of the present invention is: to provide a method capable of realizing safe hot-swapping of the secondary current loop of a substation, including the access terminal of the current secondary loop current transformer of the meter meter and the current transformer to be connected, and its characteristics yes:

A. Between the first and second connection ends of the current transformer access terminal, a plug-in reed set with first and second elastic contacts is arranged, and the central axis of the first and second elastic contacts Coincident, set in the same direction, the reed lengths of the first and second elastic contacts are not equal;

B. A plug-in board with double-sided conductive layers and mutual insulation between the two conductive layers is provided, and the conductive layers on both sides of the plug-in board are respectively electrically connected to the two ends of the primary coil of the current transformer to be connected;

C. Utilize the time difference between the conductive layer and the first and second elastic contacts of the plug-in reed group in the process of inserting or pulling out, so that the conductive layer is not in contact with the first and second elastic contacts at the same time. When the two elastic contacts are in contact or out of contact, it is ensured that a pair of contact points in the first and second elastic contacts are always in a contact/closed state during the entire insertion and extraction process of the plug-in board;

D. Set a bidirectional diode group between the first and second connection terminals of the current transformer access terminal, and use its forward conduction voltage drop to prevent the first and second elastic contacts from being disconnected at the same time for some reason. When it is open, it will cause the open circuit of the secondary current loop and affect the work of other equipment in the current loop.

Specifically, during the inserting process of the plug-in board, when its conductive layer is just in contact with the first elastic contact, the second elastic contact is still in a contact/closed state.

Or, during the pull-out process of the plug-in board, when its conductive layer is just out of contact with the second elastic contact, the second elastic contact first returns to the contact/closed state, and at this time the first elastic contact Still in contact with the conductive layer of the plug-in board.

When the plug-in board is fully inserted into the plug-in reed set, the first and second elastic contacts are in a state of keeping in contact with the conductive layer of the plug-in board.

Alternatively, when the insertion board is completely pulled out of the insertion reed set, the first and second elastic contacts are both in a contact/closed state.

The present invention also provides a device capable of realizing safe hot-swapping of the secondary current circuit of a substation, including the access terminal of the current secondary circuit current transformer of the meter meter and the current transformer to be connected, and is characterized in that: Between the first and second connection ends of the transformer access terminals, a plug-in reed set with double elastic contacts is arranged; between the first and second connection ends of the current transformer connection terminals, a two-way A diode group; an insertion board with double-sided conductive layers and mutual insulation between the two conductive layers is provided; the conductive layers on both sides of the insertion board are respectively electrically connected to the two ends of the primary coil of the current transformer to be connected.

Specifically, its plug-in reed set with double elastic contacts includes an upper spring and a lower spring, wherein the upper spring is composed of a first reed and a second reed respectively, and the lower spring is respectively composed of a third reed. It is composed of the fourth reed, and the first pair of elastic contacts are correspondingly arranged at the front ends of the first and third reeds, and the second pair of elastic contacts are correspondingly arranged at the front ends of the second and fourth reeds. It is mirror image symmetrical to the lower spring leaf structure, the lengths of the first and third reeds are greater than the lengths of the second and fourth reeds, and the first pair of elastic contacts and the second pair of elastic contacts are electrically connected in parallel .

Its bidirectional diode group includes two diodes connected in reverse and in parallel, the cathode of the first diode is connected in parallel with the anode of the second diode and then connected to the first connection end of the current transformer access terminal, and the first diode The anode of the tube is connected in parallel with the cathode of the first diode, and then connected to the second connection end of the access terminal of the current transformer.

The conductive layer on both sides of the plug-in board is the silver-coated copper foil layer on the double-sided printed circuit board.

In addition, at the front end of the plug-in board, there is no double-sided conductive layer on the surface of a section whose distance from the edge thereof is equal to or smaller than the transverse distance between the first pair of elastic contacts and the second pair of elastic contacts.

Compared with prior art, the advantages of the present invention are:

1. The elastic reed structure with unequal distance double contacts is adopted, and the dual technical means of machinery and electronics are used to ensure that the "commissioning" and "exit" of the secondary circuit are under the most simple and reliable technical protection, and realize the electrical measurement of the substation. "Hot swapping" of the secondary current circuit of the meter;

2. The dual contact point reduces the contact resistance and improves the reliability of the contact. From the mechanical structure of the contact, it ensures that the current circuit will never be open, so that the connection between the electrical measuring equipment and the secondary circuit can be fully realized. Integral plugging and unplugging ensures the personal safety and equipment safety of on-site operation, and facilitates operation, maintenance and inspection;

3. Once the double contact has poor contact or open circuit due to various reasons, the bidirectional diode will play a corresponding protective role, ensuring the continuity of the current loop and will not affect the work of other equipment in the current loop.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Figures 2 to 4 are schematic diagrams of the current flow path during the hot-swapping process of the technical solution;

Fig. 5 is a schematic diagram of the current flow path when the first and second pairs of elastic contacts are simultaneously disconnected.

In the figure, 1 is the first connection end of the current transformer access terminal, 2 is the second connection end of the current transformer access terminal, 3 is the upper spring piece, 4 is the lower spring piece, and 3-1 is the first reed piece , 3-2 is the second reed, 4-3 is the third reed, 4-4 is the fourth reed, 3-11 and 4-11 are the first pair of elastic contacts, 3-21 and 4-21 is the second pair of elastic contacts, 5 is the plug-in board, 6-1, 6-2 are the double-sided conductive layers of the plug-in board, CT is the current transformer, L1 is the primary coil of CT, L2 is the secondary coil of CT, D1 is the first diode, D2 is the second diode, J1 and J2 are the reed lengths of the first elastic contact pair and the second elastic contact pair respectively.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

In Fig. 1, this technical solution includes the access terminal of the current secondary loop current transformer of the meter meter and the current transformer CT to be connected, which is connected to the first connection end 1 and the second connection terminal of the current transformer access terminal. Between terminals 2, there is a plug-in reed group with double elastic contacts; between the first and second connection ends of the current transformer access terminals, a bidirectional diode group is set; An insertion board 5 with a conductive layer on the surface and insulation between the two conductive layers; the conductive layers 6-1 and 6-2 on both sides of the insertion board are respectively electrically connected to the two ends of the primary coil L1 of the current transformer CT to be connected.

Specifically, its plug-in reed set with double elastic contacts includes an upper spring leaf 3 and a lower spring leaf 4, the upper spring leaf is composed of a first spring leaf 3-1 and a second spring leaf 3-2 respectively, and the lower spring leaf The springs are respectively composed of a third reed 4-3 and a fourth reed 4-4, and the front ends of the first and third reeds are respectively provided with a first pair of elastic contacts 3-11 and 4-11, At the front ends of the second and fourth reeds, there are respectively a second pair of elastic contacts 3-21 and 4-21. It can be seen from the figure that the structure of the upper spring and the lower spring is a mirror image structure along the transverse central axis. , wherein the length J1 of the first and third reeds is greater than the length J2 of the second and fourth reeds, or in other words, there is a transverse distance between the first pair of elastic contacts and the second pair of elastic contacts , the value of the distance is the difference between the length J1 of the first and third reeds and the length J2 of the second and fourth reeds.

In terms of circuit relationship, the first pair of elastic contacts and the second pair of elastic contacts are electrically connected in parallel.

Its bidirectional diode group includes two reverse parallel diodes, the cathode of the first diode D1 is connected in parallel with the anode of the second diode D2, and then connected to the first connection end 1 of the current transformer access terminal, and the second The anode of one diode is connected in parallel with the cathode of the second diode, and then connected to the second connection terminal 2 of the access terminal of the current transformer.

The conductive layers 6-1 and 6-2 on both sides of the insertion board 5 are silver-coated copper foil layers on double-sided printed circuit boards.

On the front end of the plug-in board, there is no double-sided conductive layer on the surface of a section whose distance from the edge is equal to or smaller than the transverse distance between the first pair of elastic contacts and the second pair of elastic contacts. The purpose of such arrangement is to facilitate the contact or separation between the first pair of elastic contacts and/or the second pair of elastic contacts and the conductive layers 6-1 and 6-2 during the insertion or extraction process of the plug-in board.

In Fig. 2, when the CT is not put into work, the plug-in plate is not inserted into the plug-in reed group, the first pair of elastic contacts 3-11 and 4-11 and the second pair of elastic contacts 3-21 and 4 in the current circuit -21 is in the contact/closed state, the current i from the first connection end 1 to the second connection end 2 can flow through the first and/or second pair of elastic contacts, and its specific flow path is In→first Connection end 1→upper spring piece 3→first pair of elastic contacts 3-11→first pair of elastic contacts 4-11→lower spring piece 4→second connection end 2→Iout; or, from In→first connection Terminal 1→upper spring piece 3→second pair of elastic contacts 3-21→second pair of elastic contacts 4-21→lower spring piece 4→second connecting terminal 2→Iout.

It can be seen that if the plug-in board is not inserted into the plug-in reed set, there are two pairs of elastic contacts on the entire current path, and the double contact points reduce the contact resistance and improve the reliability of the contact.

In Fig. 3, when the CT is ready to be put into the working position, the plug-in board 5 starts to insert the plug-in reed group. It is in contact with the first pair of elastic contacts (also referred to as front contacts) 3-11 and 4-11.

But now the second pair of elastic contacts (also referred to as rear contacts) 3-21 and 4-21 are still in contact/closed state, the current i between the first connection end 1 and the second connection end 2 It can flow through the second pair of elastic contacts, and its specific flow path is In→first connection terminal 1→upper spring piece 3→second pair of elastic contacts 3-21→second pair of elastic contacts 4-21→bottom Spring leaf 4→second connection end 2→Iout.

At the same time, due to the existence of the internal resistance of the primary coil L1 of the current transformer and the fact that the current always flows along the path with the least resistance, the first pair of elastic contacts (ie front contacts) 3-11 and 4-11 and the double-sided No current flows between the conductive layers 6-1 and 6-2 yet.

Therefore, at this time, there is still a pair of elastic contacts on the entire current path to keep the connected state, so as to ensure that the current secondary circuit must not be opened during operation.

In Fig. 4, as the plug-in board 5 continues to be inserted into the plug-in reed group, under the action of the plug-in board insertion action, the double-sided conductive layers 6-1 and 6-2 of the plug-in board simultaneously contact with the first pair of elastic contacts ( Front contacts) 3-11, 4-11 and the second pair of elastic contacts (rear contacts) 3-21, 4-21 contact, then the current i between the first connection end 1 and the second connection end 2 It can flow through the first and/or second pair of elastic contacts and double-sided conductive layers 6-1 and 6-2 at the same time, and its specific flow path is In→first connection terminal 1→upper spring piece 3→first pair Elastic contact 3-11→conductive layer 6-1→primary coil L1 of current transformer CT→conductive layer 6-2→first pair of elastic contacts 4-11→lower spring piece 4→second connection terminal 2→Iout ; Or, from In→first connection terminal 1→upper spring piece 3→second pair of elastic contacts 3-21→conductive layer 6-1→primary coil L1 of current transformer CT→conductive layer 6-2→second For the elastic contact 4-21 → the lower spring piece 4 → the second connection end 2 → Iout.

It can be seen that as the plug-in board 5 continues to be inserted, the second pair of elastic contacts (rear contacts) are disconnected and are in contact with the double-sided conductive layers 6-1 and 6-2. At this time, the current completely passes through the secondary current transformer CT primary coil L1, then the CT enters the normal working state. At the same time, there are also two pairs of elastic contacts on the entire current path that are kept connected, and the double contact points reduce the contact resistance and improve the reliability of the contact.

Vice versa, when the plug-in board is pulled out, as it withdraws, under the premise that the current transformer circuit remains connected, the second pair of elastic contacts (rear contacts) first contact the double-sided conductive layer 6-1 Disengage from contact with 6-2 and restore the contact/closed state at first, and the connection relationship of the whole circuit returns to the state in Fig. 3, and the flow path of its current is the same as that in Fig. 3, and will not be described here.

When the plug-in board is completely pulled out, along with its withdrawal, the second pair of elastic contacts (front contacts) also disengage from the double-sided conductive layers 6-1 and 6-2 and return to the contact/closed state, the entire circuit The connection relationship returns to the state shown in Figure 2, and the current flow path is the same as that shown in Figure 2, and will not be described here.

Therefore, the mechanical structure and circuit form of the front and rear pairs of contacts are set so that during the process of inserting and withdrawing the plug-in board, there is always a pair of contacts in the contact/closed state, and its current circuit guarantees never from the circuit structure. There is a possibility of open circuit, which ensures the personal safety and equipment safety of on-site operation.

In Figure 5, once the front and rear two pairs of contacts have poor contact or open circuit due to various reasons, as long as the voltage between the first and second connection terminals exceeds 0.7V at this time, the connection between the first and second connection terminals Diode D1 or D2 will be turned on (D2 is taken as an example in the figure). Due to the circuit characteristics of the diode, the voltage drop between its two ends will not be greater than 0.7V, and the maximum power consumption will not be greater than 3.5W. Within the capacity of the primary current transformer CT, it will not affect the work of other equipment in the current loop, and it plays a corresponding protective role to ensure the continuity of the current loop.

The circuit form in which diodes are connected in parallel at the two ends of the current transformer of the measuring equipment plays a role in preventing the current loop from being opened. However, since the diode conduction is about 0.7V, and the secondary CT voltage drop is only on the order of millivolts, it is necessary for the secondary measurement The loop will not cause a shunt at all and affect its measurement accuracy. At the same time, the open circuit of the secondary CT circuit due to poor contact and other reasons is bypassed to avoid the open circuit of the secondary measurement circuit.

It can be seen that with the technical solution of the above structure, the plugging and unplugging of the entire circuit has no problem in terms of technology and safety, and the problem of plugging and unplugging the secondary circuit of the current is solved, so that the connection between the electrical measuring equipment and the secondary circuit can fully realize the overall "thermal "Plug and unplug", which provides convenience for operation, maintenance and inspection and verification.

The invention can be widely used in the field of substation electrical measurement or monitoring.

Claims (10)

1. the method that can realize safe hot plug of secondary current loop of transforming plant comprises the access terminal of survey table meter electric current secondary loop current transformer and current transformer to be accessed, it is characterized in that:

A, insert between first, second link of terminal at described current transformer, be provided with one and have the grafting reed group of first and second elastic contacts, the central axes of its first and second elastic contact, equidirectional setting, but the length of spring leaf of first and second elastic contacts is unequal;

B, an insertion plate with mutually insulated between two-sided conductive layer and two conductive layers is set, the conductive layer that inserts the plate two sides is electrically connected with the two ends of current transformer primary winding to be accessed respectively;

C, utilization are in the process of inserting the plate insertion or extracting, its conductive layer and first, second elastic contact of grafting reed group come in contact or disengage the existing time difference, make conductive layer not come in contact or disengage with first and second elastic contacts simultaneously, guarantee in the insertion and withdrawal process of whole insertion plate have a docking point to be in contact/closure state in first and second elastic contacts all the time;

D, insert between first, second link of terminal at current transformer, one two-way diode group is set, utilize its forward conduction voltage drop, prevent when causing first and second elastic contacts to disconnect simultaneously for a certain reason, cause the open circuit in described secondary current loop and the influence of other equipment works of current circuit.

2. according to the described method that realizes safe hot plug of secondary current loop of transforming plant of claim 1, it is characterized in that in the insertion process of described insertion plate, when its conductive layer just contacted with first elastic contact, described second elastic contact still was in the state of contact/closure.

3. according to the described method that realizes safe hot plug of secondary current loop of transforming plant of claim 1, it is characterized in that in the withdrawal process of described insertion plate, when its conductive layer just disengages with second elastic contact, second elastic contact at first resumes contacts/closed state, and this moment, described first elastic contact still was in the state that keeps in touch with the conductive layer that inserts plate.

4. according to the described method that realizes safe hot plug of secondary current loop of transforming plant of claim 1, it is characterized in that after described insertion plate inserts grafting reed group fully described first and second elastic contacts all are in the state that keeps in touch with the conductive layer that inserts plate.

5. according to the described method that realizes safe hot plug of secondary current loop of transforming plant of claim 1, it is characterized in that described first and second elastic contacts all are in the state of contact/closure after described insertion plate is extracted grafting reed group fully.

6. the device that can realize safe hot plug of secondary current loop of transforming plant comprises the access terminal of survey table meter electric current secondary loop current transformer and current transformer to be accessed, it is characterized in that:

Insert at current transformer between first, second link of terminal, be provided with one and have the grafting reed group of two elastic contacts, this grafting reed group with two elastic contacts comprises the grafting reed group of first and second elastic contacts, the central axes of its first and second elastic contact, equidirectional setting, but the length of spring leaf of first and second elastic contacts is unequal;

Insert at current transformer between first, second link of terminal, a two-way diode group is set;

The one insertion plate with mutually insulated between two-sided conductive layer and two conductive layers is set;

The conductive layer that inserts the plate two sides is electrically connected with the two ends of current transformer primary winding to be accessed respectively.

7. according to the described device of realizing safe hot plug of secondary current loop of transforming plant of claim 6, it is characterized in that described grafting reed group with two elastic contacts comprises upper spring sheet and lower spring sheet, its upper spring sheet is made of first reed and second reed respectively, its lower spring sheet is made of the 3rd reed and the 4th reed respectively, first, the front end of the 3rd reed, correspondence is provided with first pair of resilient contact, front end at the second and the 4th reed, correspondence is provided with second pair of resilient contact, upper spring sheet and lower spring chip architecture mirror image symmetry, it is first years old, the length of the 3rd reed greater than its second, the 4th length of spring leaf, and be the electric relation of being connected in parallel between first pair of resilient contact and second pair of resilient contact.

8. according to the described device of realizing safe hot plug of secondary current loop of transforming plant of claim 6, it is characterized in that described bidirectional diode group comprises two reverse and connect diodes, the back anodal in parallel of the negative pole of its one or two utmost point and second diode is connected with first link that current transformer inserts terminal, is connected with second link of current transformer access terminal after the negative pole parallel connection of the positive pole of its first diode and second diode.

9. according to the described device of realizing safe hot plug of secondary current loop of transforming plant of claim 6, the conductive layer that it is characterized in that described insertion plate two sides is the silver-colored copper foil layer that is coated with on the printed on both sides wiring board.

10. according to the described device of realizing safe hot plug of secondary current loop of transforming plant of claim 6, it is characterized in that front end at described insertion plate, be equal to or less than one section surface of horizontal spacing between the first pair of resilient contact and the second pair of resilient contact apart from its Edge Distance, do not have two-sided conductive layer.

Images