Temporary protection device for uninterruptible power transformation of protection device

Abstract

The utility model discloses a temporary protection device for reconstruction of a protection device without power outage, which comprises an induction type pincerlike current sampling component, a temporary protection component and a tripping start holding loop parallel connection component which are sequentially connected in series, and the tripping start holding loop parallel connection component is electrically connected with a circuit breaker of an original protection device. According to the utility model, the non-tandem type inductive pincerlike current sampling part is adopted, current monitoring can be completed without disconnecting a circuit, the tripping starting maintaining loop parallel connection part with adjustable starting current is adopted, specification requirements in various operation states can be met at the same time, and in the process of replacing an original protection device with a new protection device, the operation efficiency is greatly improved. The function of the original protection device is seamlessly provided, and the protected equipment is ensured not to lose protection in the whole process of remodeling and transformation of the protection device, so that the protected equipment does not need to be powered off.

Description

Technical Field

[0001] The utility model relates to the technical field of substation protection devices, and particularly relates to a temporary protection device for the power-off transformation of protection devices. Background Technique

[0002] The relay protection device is a necessary device to ensure the safe operation of primary equipment in a substation. Its basic function is to monitor in real time the electrical quantity data such as current and voltage of the primary equipment operating in the substation. When it detects that the electrical quantity conforms to the characteristics of a primary equipment failure, it automatically, quickly and selectively cuts off the faulty equipment from the power system, so that the faulty equipment is prevented from being further damaged, and it ensures that other fault-free equipment is not affected and keeps normal operation. Therefore, when the primary equipment in the power system is operating, a corresponding relay protection device must be operating. Considering safe operation, when the relay protection device is out of service, the primary equipment it protects must be out of service.

[0003] The service life of the microcomputer-based relay protection devices widely used in the current power system is 10 to 15 years. When it comes to the replacement and transformation period of microcomputer protection devices, during the transformation process from the removal of the original protection device to the completion of the installation, commissioning and debugging of the new protection device, the protected equipment will lose protection, so it is necessary to cut off the power supply to the protected equipment. Generally, the process of replacing and transforming microcomputer protection devices includes: removing the old device, installing the new device, checking the wiring, performing protection function tests, communication debugging, etc. The duration is relatively long, and it requires long-term power-off operations, which have a greater impact on the electricity consumption of enterprises, residents and public facilities. Content of the Utility Model

[0004] Purpose of the Invention: The purpose of the utility model is to provide a temporary protection device for the power-off transformation of protection devices with a simple structure and convenient operation.

[0005] Technical Solution: A temporary protection device for the power-off transformation of protection devices includes: an induction clamp current sampling component, a temporary protection component, and a trip start and hold loop parallel connection component connected in series in sequence. The trip start and hold loop parallel connection component is electrically connected to the circuit breaker; the trip start and hold loop parallel connection component includes a TBJ relay and several resistors, the resistors are connected in parallel with each other, and the TBJ relay is selectively connected in series with any one of the resistors.

[0006] Preferably, the trip start and hold loop parallel connection component includes 5 resistors.

[0007] Preferably, the above-mentioned relay is a TBJ relay.

[0008] Specifically, the inductive clamp - type current sampling component includes a clamp - type ring clip and an induction magnetic ring. One end of the clamp - type ring clip is an openable and closable ring structure. A rotating shaft is fixed in the middle of the clamp - type ring clip, and the other end is a pair of handles that drive the ring structure to open and close through the rotating shaft. The induction magnetic ring is arranged inside the ring structure of the clamp - type ring clip. When the ring structure is closed, the induction magnetic ring forms a closed loop.

[0009] Specifically, a spring is arranged inside the clamp - type ring clip, which keeps the ring structure in a closed state when the handle is not manipulated.

[0010] Preferably, the parallel connection interface of the trip - start holding circuit parallel connection component is a threaded structure.

[0011] Specifically, the temporary protection component is a microcomputer - type relay protection component.

[0012] Beneficial effects: Compared with the prior art, the advantages of the present utility model are as follows: The present utility model designs a temporary protection device, which adopts a non - series inductive clamp - type current sampling component, and can complete current monitoring without disconnecting the circuit. It adopts a trip - start holding circuit parallel connection component with adjustable starting current, which can meet the specification requirements under various operating conditions at the same time. During the process of replacing the original protection device with a new one, it can seamlessly provide the functions of the original protection device, ensuring that the protected equipment does not lose protection throughout the whole process of the protection device transformation, and enabling the protected equipment to operate without power outage. Description of the Drawings

[0013] Figure 1 It is a schematic diagram of the overall structure of the present utility model.

[0014] Figure 2 It is a schematic diagram of the inductive clamp - type current sampling component of the present utility model.

[0015] Figure 3 It is a schematic diagram of the cooperation between the parallel connection interface of the trip - start holding circuit parallel connection component of the present utility model and the switch cabinet terminal block.

[0016] Figure 4 It is a circuit diagram of the trip - start holding circuit parallel connection component of the present utility model.

[0017] Figure 5 It is a circuit diagram of the trip - start holding circuit parallel connection component of the present utility model in the non - power - outage transformation state 1.

[0018] Figure 6 It is a circuit diagram of the trip - start holding circuit parallel connection component of the present utility model in the non - power - outage transformation state 2.

[0019] Figure 7 It is a circuit diagram of the trip - start holding circuit parallel connection component of the present utility model in the non - power - outage transformation state 3.

[0020] Figure 8This is the circuit diagram of the 4th state of the modification without power interruption for the parallel-connected component of the trip start and hold circuit of the present utility model.

[0021] Figure 9 This is the circuit diagram of the 5th state of the modification without power interruption for the parallel-connected component of the trip start and hold circuit of the present utility model.

[0022] Figure 10 This is the schematic circuit diagram of each stage state for the work process of the modification without power interruption of the present utility model. Specific implementation manner

[0023] The technical solution of the present utility model will be further described below in conjunction with the accompanying drawings and specific implementation manners.

[0024] Please refer to Figure 1 As shown, the present utility model provides a temporary protection device for the modification without power interruption of a protection device, including: an inductive clamp current sampling component 1, a temporary protection component 2, and a parallel-connected component 3 of the trip start and hold circuit connected in series in sequence. The inductive clamp current sampling component 1 non-serially monitors the secondary output current of the current transformer 4 that senses the protected line 5. The parallel-connected component 3 of the trip start and hold circuit is electrically connected to the circuit breaker 6 connected to the original protection device to be replaced / modified. The temporary protection component 2 is a microcomputer-based relay protection component of the same type as the original protection device.

[0025] Please refer to Figure 2 As shown, the above-mentioned inductive clamp current sampling component 1 includes a clamp-shaped ring clamp 11 and an induction magnetic ring. One end of the clamp-shaped ring clamp 11 is an openable and closable ring structure. A rotating shaft 111 is fixed in the middle of the clamp-shaped ring clamp 11. The other end is a pair of handles that drive the ring structure to open and close through the rotating shaft 111. The induction magnetic ring is arranged inside the ring structure of the clamp-shaped ring clamp 11. When the ring structure is closed, the induction magnetic ring forms a closed loop. A spring is arranged inside the clamp-shaped ring clamp 11. When the handle is not manipulated, the ring structure is in a closed state. Please refer to Figure 2 Subfigure a. When the handle is pinched, the ring structure is in an open state. Please refer to Figure 2 Subfigure b. When the handle is released, the ring structure returns to the closed state. Through the above operations, the non-series measurement of the secondary output current of the current transformer 4 is realized.

[0026] Please refer to Figure 3 As shown, the parallel connection interface 31 of the parallel-connected component 3 of the trip start and hold circuit is a threaded structure and can be fastened in cooperation with the reserved screw hole 71 of the switch cabinet terminal block 7, so that the protection side wiring 72, the circuit breaker 6 trip coil side wiring 73, and the temporary protection side wiring 32 are short-circuited through the internal shorting piece 74 of the terminal block.

[0027] Please refer to Figure 4 As shown, the parallel-connected component 3 of the trip start and hold circuit ( Figure 4Inside the left dashed box a) includes relay TBJ2 and several resistors, which are connected in parallel with each other. Relay TBJ2 can be selectively connected in series with any group of resistors through lead terminals 0 - 4 and is connected to the trip coil of circuit breaker 6 ( Figure 4 connected to b) inside the right dashed box, thus realizing multi - stage adjustment of the starting current of the trip circuit.

[0028] The feasibility and necessity of the solution of the present utility model will be described below.

[0029] Figures 4 - 9 The same reference numerals are used throughout, specifically: in the dashed box a is the trip start - hold circuit of the temporary protection device, in the dashed box b is the trip coil of the circuit breaker, in the dashed box c is the trip start - hold circuit of the original protection device, and in the dashed box d is the trip start - hold circuit of the new protection device.

[0030] The parallel component 3 of the trip start - hold circuit of the present utility model is designed with adjustable starting current. The trip of the protected device by the protection device is realized through the circuit breaker. The basic process is as follows, please refer to Figure 5 as shown:

[0031] State 1: When the trip output BHT1 of the protection device closes, the trip start circuit is turned on, and the current I flowing through the trip hold relay TBJ1 n = U n / (R qd1 + R tq ), where U n is the rated voltage of the operating circuit, R qd1 is the impedance of the trip start circuit, and R tq is the impedance of the circuit breaker coil. Since R qd1 is much smaller than R tq , I n ≈ U n / R tq ;

[0032] If I n is greater than the starting current I qd1 of the trip circuit, then the trip hold relay TBJ1 operates; when the trip hold relay TBJ1 operates, its output contact TBJ1b closes; when the output contact TBJ1b of the trip hold relay closes, the trip hold circuit is turned on; at this time, even if the protection trip output BHT1 returns, the trip hold circuit remains on, and the operating circuit voltage U n is continuously applied to the trip coil of the circuit breaker, causing the trip coil of the circuit breaker to operate and trip the circuit breaker; after the circuit breaker trips, the auxiliary contact DL of the trip coil disconnects, and at this time, all the trip start - hold circuits are disconnected, and the trip process ends.

[0033] According to the specification requirements, I designed in the protection start - trip circuitqd1 , the safe and reliable operation conditions of the following formula (1) shall be satisfied. If I qd1 / I n <0.2, the protection startup trip is too sensitive and there is a risk of mis-startup. If I qd1 / I n >0.5, the sensitivity of the protection startup trip is insufficient and there is a risk of startup failure.

[0034] 0.2 < I qd1 / I n <0.5 (1)

[0035] Based on the temporary protection of the present utility model, the steps for changing the trip startup holding circuit during the replacement of the original protection device with a new protection device are as follows:

[0036] Connect the parallel component of the trip startup holding circuit of the temporary protection device to the trip startup holding circuit of the original protection device; remove the trip startup holding circuit of the original protection device; install the trip startup holding circuit of the new protection device; remove the trip startup holding circuit of the temporary protection device.

[0037] State 2: Please refer to Figure 6 As shown, the trip startup holding circuit of the temporary protection device is connected in parallel to the trip startup holding circuit of the original protection device. In this state, if a fault occurs in the protected device and the protection trip outputs BHT1 and BHT2 of the original protection device and the temporary protection device act simultaneously, the current I n through the circuit breaker trip coil is shunted to the trip startup branch circuits of the two protection devices, and the branch circuit split currents I n1 , I n2 and the impedances R qd1 , R qd2 are inversely proportional. Respectively:

[0038] I n1 = I n *R qd2 / (R qd1 + R qd2 )

[0039] I n2 = I n *R qd1 / (R qd1 + R qd2 )

[0040] The condition for the reliable operation of the original protection trip startup circuit in this state is:

[0041] 0.2 < I qd1 / I n1 <0.5

[0042] That is: 0.2 < Iqd1 / (I n *R qd2 / (R qd1 +R qd2 )) < 0.5

[0043] Further calculation gives: 0.2 * R qd2 / (R qd1 +R qd2 ) < I qd1 / I n < 0.5 * R qd2 / (R qd1 +R qd2 )(2)

[0044] The condition for the reliable operation of the temporary protection trip start circuit is:

[0045] 0.2 < I qd2 / I n2 < 0.5

[0046] That is: 0.2 < I qd2 / (I n *R qd1 / (R qd1 +R qd2 )) < 0.5

[0047] Further calculation gives: 0.2 * R qd1 / (R qd1 +R qd2 ) < I qd2 / I n < 0.5 * R qd1 / (R qd1 +R qd2 )(3)

[0048] To ensure that the circuit breaker can be reliably tripped when a fault occurs in the protected equipment, at least one of the original protection device and the temporary protection device needs to have a reliable operation of the protection trip start circuit. That is, at least one of Equation (2) and Equation (3) is satisfied in State 2.

[0049] If 0.5 * R qd2 / (R qd1 +R qd2 ) < I qd1 / I n < 0.5, then Equation (1) is satisfied while Equation (2) is not. In this case, the original protection device meets the specification requirements, and in State 2, the safe and reliable tripping of the circuit breaker must be achieved by satisfying Equation (3).

[0050] State 3: Please refer to Figure 7As shown, after removing the trip start hold circuit of the original protection device, only the trip start hold circuit of the temporary protection device and the breaker trip coil are connected in series. When the trip outlet BHT2 of the temporary protection operates, the current flowing through its trip start circuit is I n , the condition for the reliable operation of the trip start circuit of the temporary protection in state 3 is:

[0051] 0.2 < I qd2 / I n <0.5(4)

[0052] State 4: Please refer to Figure 8 As shown, connect the trip start hold circuit of the new protection device. When the protection trip outlets BHT3 and BHT2 of the new protection device and the temporary protection device operate simultaneously, the current I n is shunted to the trip start branch circuits of the two protection devices, and the branch currents I n3 、I n2 and the impedances R qd3 、R qd2 are inversely proportional. Respectively:

[0053] I n3 =I n *R qd2 / (R qd3 +R qd2 )

[0054] I n2 =I n *R qd3 / (R qd3 +R qd2 )

[0055] The condition for the reliable operation of the new protection trip start circuit in this state is:

[0056] 0.2 < I qd3 / I n3 <0.5

[0057] That is: 0.2 < I qd3 / (I n *R qd2 / (R qd3 +R qd2 )) < 0.5

[0058] Further calculation gives: 0.2*R qd2 / (R qd3 +R qd2 ) < I qd3 / I n <0.5*R qd2 / (R qd3 +R qd2)(5)

[0059] The conditions for the reliable operation of the temporary protection tripping start loop are as follows:

[0060] 0.2 < I qd2 / I n2 <0.5

[0061] That is: 0.2 < I qd2 / (I n *R qd3 / (R qd3 +R qd2 )) < 0.5

[0062] Further calculation gives: 0.2*R qd3 / (R qd3 +R qd2 ) < I qd2 / I n <0.5*R qd3 / (R qd3 +R qd2 )(6)

[0063] To ensure that the circuit breaker can be reliably tripped when a fault occurs in the protected device, at least one of the protection tripping start loops in the new protection device and the temporary protection device needs to operate reliably. That is, at least one of Equation (5) and Equation (6) is satisfied in State 4.

[0064] State 5: Please refer to Figure 9 As shown, after removing the tripping start holding loop of the temporary protection device, only the tripping start holding loop of the new protection device and the circuit breaker tripping coil are connected in series. When the tripping outlet BHT3 of the new protection device operates, the current flowing through its tripping start loop is I n , and the conditions for the reliable operation of the new protection tripping start loop in State 5 are:

[0065] 0.2 < I qd3 / I n <0.5(7)

[0066] If 0.5*R qd2 / (R qd3 +R qd2 ) < I qd3 / I n <0.5, then Equation (7) is satisfied while Equation (5) is not satisfied. In this case, the new protection device meets the specification requirements, and in State 4, the safe and reliable tripping of the circuit breaker must be achieved by satisfying Equation (6).

[0067] Summarize the conditions that the start current of each protection tripping loop needs to meet in each state:

[0068] In State 1, Equation (1) should be satisfied; in State 2, Equation (3) should be satisfied; in State 3, Equation (4) should be satisfied; in State 4, Equation (6) should be satisfied; in State 5, Equation (7) should be satisfied.

[0069] Among them, the conditions for State 1 and State 5 are ensured by the original protection device and the new protection device itself, while for States 2 to 4, the temporary protection device needs to select an appropriate tripping start loop current I qd2 and tripping start loop impedance R qd3 to ensure.

[0070] Assume I qd2 / I n is fixed. Then, when 0.5*R qd1 / (R qd1 +R qd2 ) < 0.2, Equation (3) required for State 2 and Equation (4) required for State 3 cannot be satisfied simultaneously; when 0.5*R qd3 / (R qd3 +R qd2 ) < 0.2, Equation (6) required for State 4 and Equation (4) required for State 3 cannot be satisfied simultaneously.

[0071] Therefore, the tripping start loop current I qd2 of the temporary protection needs to be designed to be adjustable. It should be adjusted to meet the requirement of Equation (3) in State 2, adjusted to meet the requirement of Equation (4) in State 3, and adjusted to meet the requirement of Equation (6) in State 4. Therefore, it is necessary to Figure 4 add a shunt resistor to the tripping start loop in the manner shown. There are multiple choices for the shunt resistor, which is led out from the shunt point, and an appropriate shunt resistor value can be selected during the transformation process.

[0072] Please refer to Figure 4 as shown. The current I n2 flowing through the tripping start loop with a shunt resistor is divided into the current I n2a flowing through the start relay and the current I n2b flowing through the shunt resistor. The shunt ratio is inversely proportional to the branch impedance value, that is:

[0073] I n2a = I n2 *R qd2b / (R qd2a +R qd2b )(8)

[0074] I n2b = I n2 *R qd2a / (R qd2a +R qd2b )(9)

[0075] The current flowing through the starting relay decreases to R before the parallel resistor qd2b / (R qd2a +R qd2b ). In this way, if the branch current flowing through the starting relay is to reach the starting current I qd2a , then the total loop current I qd2 needs to reach I qd2a *(R qd2a +R qd2b ) / R qd2b . In this way, by selecting different parallel resistors R qd2b , the I qd2 of the trip starting circuit can be changed. Five different resistor value schemes are given in the figure. For example, if the lead terminal 0 is connected to the lead terminal 4, then R qd2b0 and R qd2b4 are connected in series to the circuit. At this time, the two resistors can be regarded as a resistor with a fixed resistance value.

[0076] The following describes a typical working process of the present utility model with reference to Figure 10 :

[0077] (1) Figure 10 Subfigure a shows the initial state. Open the trip outlet pressure plate of the temporary protection device, power on and run. Set the fixed value according to the original protection device. Connect the voltage input wiring of the temporary protection device to the voltage terminal on the switch cabinet terminal block. Then close the clamp-shaped ring of the inductive clamp current sampling component of the temporary protection device around the front end of the current sampling circuit access point of the original protection device in the secondary output circuit of the current transformer. The state at this time is as shown in subfigure b, and the induction magnetic ring can measure the secondary output current of the current transformer.

[0078] (2) Adjust the trip starting current of the trip starting holding circuit of the temporary protection device to meet the condition of formula (3). Short-circuit the current sampling circuit access point of the original protection device in the secondary output circuit of the current transformer. Please refer to subfigure c. The secondary output circuit of the current transformer changes from an "O" shape to an "8" shape. At this time, the secondary output current of the current transformer passes through the clamp-shaped ring of the inductive clamp current sampling component of the temporary protection device and does not flow through the current sampling circuit of the original protection device. Check the sampling value and breaker position of the temporary protection device. After confirming normal, close the trip outlet pressure plate to put the temporary protection device into operation.

[0079] (3) Open the trip output pressure plate of the original protection device, withdraw its protection function, and adjust the trip start current of the trip start holding circuit of the temporary protection device to meet the conditions of formula (4); short-circuit the front end of the sampling circuit of the original protection device in the secondary output circuit of the current transformer, disconnect the current input wiring of the original protection device, disconnect the current sampling circuit of the original protection device, disconnect the voltage input wiring of the original protection device, and remove the chassis of the original protection device. Please refer to the sub-figure d shown, and finally open the loop of the lower ring of the "8" shape.

[0080] (4) Install the chassis of the new protection device, open the trip output pressure plate of the new protection device, withdraw its protection function, and connect the current input wiring disconnected from the original protection device to the same-name terminal of the new protection device, so that the current sampling circuit of the new protection device replaces the current sampling circuit of the original protection device. Please refer to the sub-figure e shown to form a closed loop of the lower ring.

[0081] (5) Remove the short-circuit of the front end of the sampling circuit of the original protection device in the secondary output circuit of the current transformer, connect the voltage input wiring disconnected from the original protection device to the same-name terminal of the new protection device, connect it to the trip start holding circuit of the new protection device, power on the new protection device for operation, set the values according to the original protection device, check the sampling values and breaker positions of the new protection device. After confirming normal, close the trip output pressure plate to put the temporary protection device into operation. Adjust the trip start current of the trip start holding circuit of the temporary protection device to meet the conditions of formula (6). Please refer to the sub-figure f shown. The secondary output circuit of the current transformer is restored from the "8" shape to the "0" shape, and the current sampling circuit of the new protection device is connected in series in the "0" shape circuit to obtain the secondary output current of the current transformer.

[0082] (6) Open the trip output pressure plate of the temporary protection device, power it on for operation, set the values according to the original protection device, disconnect the voltage input wiring of the temporary protection device from the switchgear terminal block, remove the clamp-shaped ring of the inductive clamp current sampling component of the temporary protection device from the secondary output circuit of the current transformer, and remove the trip start holding circuit of the temporary protection device. Please refer to the sub-figure g shown to complete the replacement work of the new protection device.

[0083] The above operations can not only avoid the open circuit of the secondary output circuit of the current transformer, but also ensure that there is always a protection device obtaining the secondary output current of the current transformer during the whole operation process, maintaining the protection function for the line to be protected.

Claims

1. A temporary protection device for the power-off transformation of a protection device, characterized in that Comprising: An inductive clamp current sampling component (1), a temporary protection component (2), and a tripping start-up holding circuit parallel connection component (3) connected in series in sequence, where the tripping start-up holding circuit parallel connection component (3) is electrically connected to a circuit breaker (6); the tripping start-up holding circuit parallel connection component (3) includes a relay and several resistors, the resistors are connected in parallel with each other, and the relay is selectively connected in series with any one of the resistors.

2. The temporary protection device for the power-off transformation of the protection device according to claim 1, wherein: The inductive clamp current sampling component (1) includes a clamp-shaped ring clip (11) and an induction magnetic ring, the induction magnetic ring is electrically connected to the temporary protection component (2), one end of the clamp-shaped ring clip is an openable and closable ring structure, a rotating shaft (111) is fixed in the middle of the clamp-shaped ring clip, and the other end is a pair of handles that drive the ring structure to open and close through the rotating shaft (111), and the induction magnetic ring is arranged inside the ring structure of the clamp-shaped ring clip (11). When the ring structure is closed, the induction magnetic ring forms a closed loop.

3. The temporary protection device for the power-off transformation of the protection device according to claim 2, characterized in that: A spring is arranged inside the clamp-shaped ring clip (11).

4. The temporary protection device for the power-off transformation of the protection device according to claim 1, wherein: The parallel connection interface (31) of the tripping start-up holding circuit parallel connection component (3) is a threaded structure.

5. The temporary protection device for the power-off transformation of the protection device according to claim 1, characterized in that: The temporary protection component is a microcomputer-based relay protection component.

6. The temporary protection device for the power-off transformation of the protection device according to claim 1, characterized in that: The tripping start-up holding circuit parallel connection component (3) includes 5 resistors.

7. The temporary protection device for the power-off renovation of the protection device according to claim 1, characterized in that: The relay is a TBJ relay.

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