High-voltage rapid shunting device of generator set and power generation system

Abstract

The invention relates to a high-voltage rapid shunting device for a generator set and a power generation system, and the device comprises a first transient current transformer, a first fuse, a first circuit breaker, a second circuit breaker, a second fuse, an overvoltage limiter, a monitoring device, and a control device. Each transient current transformer detects a cut-off current signal in a circuit where the transient current transformer is located, and the monitoring device monitors the internal operation condition of the generator, so that when the transient current transformers detect the cut-off current signal of a short-circuit fault of a generator-transformer loop, the short-circuit fault of the generator-transformer loop is detected; the control device respectively drives the second circuit breaker to be quickly switched on and the first circuit breaker to be switched off, so that short-circuit fault current is shunted through the second fuse connected in parallel, the magnitude of main loop short-circuit current of the circuit breakers is changed, and the main loop short-circuit direct-current component of the first circuit breaker is smaller than 20%. The adverse effect on solving the short-circuit fault of the generator due to the fact that a common circuit breaker cannot cut off the direct-current component is avoided.

Description

Technical Field

[0001] The present invention relates to the field of oil refining and chemical engineering, and particularly to a high-voltage fast shunt device for a generator set and a power generation system. Background Art

[0002] In oil refining and chemical enterprises, since cogeneration of steam and electricity is one of the important measures for the power system of refining and chemical enterprises, the safe operation of steam turbine generator sets is particularly important. Once a short-circuit fault occurs in the generator set, it is required to immediately disconnect the unit to ensure the stability of the whole plant power grid system.

[0003] In order to cope with the short-circuit fault of the generator set, currently, usually, a current transfer type generator circuit breaker or a high-voltage fast current-limiting device is added to achieve the effect of quickly breaking the short-circuit current.

[0004] First of all, using a current transfer type generator circuit breaker to cope with circuit faults has the advantages of quickly breaking the short-circuit current, large breaking current, and strong breaking ability. However, it is necessary to transfer the short-circuit current to the current-limiting branch to break the short-circuit current. During the transfer process of the short-circuit current, there is a risk that the short-circuit fault cannot be removed because the fast switch fails to perform the action or the current in the vacuum interrupter does not reach the arc extinguishing effect.

[0005] Secondly, using a high-voltage fast current-limiting device also has the advantages of fast breaking speed, large breaking current, and strong breaking ability. However, it is also necessary to transfer the short-circuit current to the high-voltage fast current-limiting device to break the short-circuit current. During the transfer process of the short-circuit current, there is a risk that the original circuit breaker cannot complete the tripping action due to the existence of the DC component. Once there is an overcurrent or overloading condition in the system, the fuse of the high-voltage fast current-limiting device may be melted due to overcurrent, resulting in the inability to break the short-circuit current, which will bring great risks to the operation of the whole system. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide a high-voltage fast shunt device for a generator set in view of the above-mentioned prior art. The high-voltage fast shunt device for a generator set can effectively solve the generator short-circuit fault and avoid the adverse impact on solving the generator short-circuit fault caused by the inability of the circuit breaker to cut off the DC component.

[0007] The second technical problem to be solved by the present invention is to provide a power generation system applying the above-mentioned high-voltage fast shunt device for a generator set.

[0008] The technical solution adopted by the present invention to solve the first technical problem is: a high-voltage fast shunt device for a generator set, which is configured to cooperate with the loop formed by a generator and a transformer. The transformer has a low-voltage side and a high-voltage side, and the transformer is configured to be connected to the power grid system. It is characterized in that the high-voltage fast shunt device for a generator set includes:

[0009] A first transient current transformer, configured to be connected to a generator and detect a breaking current signal at the generator.

[0010] A first fuse, the first end of which is configured to be connected to the voltage output terminal of the generator by connecting a second transient current transformer in series; wherein, the second transient current transformer is configured to detect a breaking current signal in the circuit where it is located.

[0011] A first circuit breaker, the first end of which is connected to the second end of the first fuse, and the second end of the first circuit breaker is configured to be connected to the low-voltage side of a transformer by connecting a third transient current transformer in series, and the high-voltage side of the transformer is connected to the power grid system; wherein, the third transient current transformer is configured to detect a breaking current signal in the circuit where it is located.

[0012] A second circuit breaker, the first end of which is connected to the first end of the first fuse.

[0013] A second fuse, the first end of which is connected to the second end of the second circuit breaker, and the second end of the second fuse is connected to the second end of the first circuit breaker.

[0014] An overvoltage limiter, the first end of which is connected to the first end of the first fuse, and the second end of the overvoltage limiter is connected to the second end of the first circuit breaker.

[0015] A monitoring device, configured to monitor the internal operating condition of the generator.

[0016] A control device, respectively connected to the first transient current transformer, the second transient current transformer, the third transient current transformer and the monitoring device, and according to the breaking current signals sent by each transient current transformer, to drive the first circuit breaker to trip and the second circuit breaker to close when a short-circuit fault occurs in the loop formed by the generator and the transformer.

[0017] Improved, in the high-voltage fast shunt device of the generator set, the second circuit breaker is a high-voltage load switch.

[0018] Further improved, in the high-voltage fast shunt device of the generator set, the internal operating condition of the generator includes the phase-to-phase condition of the generator, the turn-to-turn winding condition, the stator condition and the rotor condition.

[0019] Furthermore, in the high-voltage fast shunt device of the generator set, the monitoring device is configured to be arranged inside the generator.

[0020] Further improved, in the high-voltage fast shunt device of the generator set, the control device drives the first circuit breaker to trip and the second circuit breaker to close according to the internal operating condition signal of the generator sent by the monitoring device when the internal operating condition of the generator is abnormal.

[0021] The technical solution adopted by the present invention to solve the second technical problem is as follows: a power generation system, including a generator and a transformer, the generator and the transformer form a loop, the transformer has a low-voltage side and a high-voltage side, and the transformer is configured to be connected to a power grid system; characterized in that the high-voltage fast shunt device of the generator set described in any one of the above is applied.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] First of all, the high-voltage fast shunt device of the generator set of the present invention detects the interrupted current signal in the circuit where it is located by setting a transient current transformer, a first fuse, a first circuit breaker, a second circuit breaker, a second fuse and an overvoltage limiter, and sets the connection relationship between the electrical components, and then by adding a transient current transformer to detect the interrupted current signal in the circuit where it is located and adding a monitoring device to monitor the internal operation of the generator. Thus, when the transient current transformer detects the interrupted current signal of a short-circuit fault in the generator-transformer loop, the control device drives the second circuit breaker to close quickly and the first circuit breaker to trip respectively. In this way, the short-circuit fault current is shunted through the parallel second fuse, thereby changing the magnitude of the short-circuit current in the main circuit of the circuit breaker, making the DC component of the short-circuit current in the main circuit of the first circuit breaker < 20%, avoiding the adverse impact on solving the generator short-circuit fault caused by the inability of an ordinary circuit breaker to cut off the DC component.

[0024] Secondly, the second fuse is protected and set so that before the first circuit breaker is fully tripped, the second fuse does not reach the fuse setting value and cannot interrupt the short-circuit current. After the first circuit breaker is fully tripped, all the short-circuit fault current flows through the second fuse, and the second fuse interrupts the short-circuit current, and the overvoltage generated by cutting off the interrupted current is protected by the overvoltage limiter F. Description of the Drawings

[0025] Figure 1 It is a schematic diagram of the high-voltage fast shunt device of the generator set in the embodiment of the present invention. Detailed Embodiment

[0026] The present invention will be further described in detail below with reference to the embodiments of the drawings.

[0027] This embodiment provides a high-voltage fast shunt device for a generator set, and the high-voltage fast shunt device for the generator set is configured to cooperate with the loop formed by the generator G and the transformer TR. The transformer TR has a low-voltage side and a high-voltage side, and the transformer TR is configured to be connected to a power grid system. Refer to Figure 1 As shown, the high-voltage fast shunt device for the generator set of this embodiment includes:

[0028] A first transient current transformer TA1, configured to be connected to the generator G to detect the interrupted current signal at the generator G;

[0029] The first fuse FU1, whose first end is configured to be connected to the voltage output terminal of the generator G by connecting in series with the second transient current transformer TA2; wherein, the second transient current transformer TA2 is configured to detect the breaking current signal in the circuit where it is located;

[0030] The first circuit breaker QF1, whose first end is connected to the second end of the first fuse FU1, and the second end of the first circuit breaker QF1 is configured to be connected to the low-voltage side of the transformer TR by connecting in series with the third transient current transformer TA3, and the high-voltage side of the transformer TR is connected to the power grid system; wherein, the third transient current transformer TA3 is configured to detect the breaking current signal in the circuit where it is located;

[0031] The second circuit breaker QF2, whose first end is connected to the first end of the first fuse FU1; for example, the second circuit breaker QF2 here is a high-voltage load switch;

[0032] The second fuse FU2, whose first end is connected to the second end of the second circuit breaker QF2, and the second end of the second fuse FU2 is connected to the second end of the first circuit breaker QF1;

[0033] The overvoltage limiter F, whose first end is connected to the first end of the first fuse FU1, and the second end of the overvoltage limiter F is connected to the second end of the first circuit breaker QF1;

[0034] The monitoring device F2 monitors the internal operating conditions of the generator G; for example, the internal operating conditions of the generator G here include the phase conditions between phases of the generator, the turn-to-turn winding conditions, the stator conditions, and the rotor conditions; wherein, according to actual needs, the monitoring device F2 can be arranged inside the generator;

[0035] The control device F1 is respectively connected to the first transient current transformer TA1, the second transient current transformer TA2, the third transient current transformer TA3, and the monitoring device F2, and according to the breaking current signals sent by each transient current transformer, it drives the first circuit breaker QF1 to trip and the second circuit breaker QF2 to close when a short-circuit fault occurs in the loop formed by the generator and the transformer.

[0036] Specifically in this embodiment:

[0037] (1) The relevant parameters of the generator G are as follows:

[0038] Direct-axis subtransient reactance: 0.148

[0039] Power factor: 0.8

[0040] (2) The relevant parameters of the transformer TR are as follows:

[0041] Rated capacity: 75 MVA

[0042] Rated voltage on the high voltage side: 35 kV

[0043] Rated voltage on the low voltage side: 10.5 kV

[0044] Short-circuit impedance: 10.5%

[0045] Connection group: Dyn11

[0046] Insulation class: Class H

[0047] Cooling method: ONAN

[0048] Bushing terminal on the high voltage side: A, B, C

[0049] Bushing terminal on the low voltage side: a, b, c (10.5 kV)

[0050] In order to avoid damaging the generator due to abnormal internal operating conditions of the generator, in the high-voltage fast shunt device of the generator set in this embodiment, the control device F1 will also drive the first circuit breaker QF1 to trip and the second circuit breaker QF2 to close according to the internal operating condition signal of the generator G sent by the monitoring device F2 when the internal operating condition of the generator G is abnormal. For example, when an abnormal operating condition inside the generator is detected, the control device F1 issues a closing command to drive the second circuit breaker QF2 to close quickly, and issues a tripping command to drive the first circuit breaker QF1 to trip, so that abnormal operating conditions can be predicted and maintained in advance to prevent the generator from being damaged.

[0051] The following combines Figure 1 , to illustrate the working principle of the high-voltage fast shunt device of the generator set in this embodiment:

[0052] When the generator-transformer circuit is operating normally, the load current passes through the first fuse FU1, the first circuit breaker QF1, the transformer TR to the whole plant power grid system; when a short-circuit fault occurs in the generator-transformer circuit, any transient current transformer detects the cut-off current signal and sends it to the control device F1. The control device F1 issues a closing command to drive the second circuit breaker QF2 using a high-voltage load switch to close quickly, and the control device F1 issues a tripping command to drive the first circuit breaker QF1 to trip. The short-circuit fault current is shunted through the parallel second fuse FU2, so that the short-circuit DC component of the main circuit of the first circuit breaker QF1 < 20%; the second fuse FU2 is set by protection, so that before the first circuit breaker QF1 is fully tripped, the second fuse FU2 does not reach the fusing setting value and cannot interrupt the short-circuit current. After the first circuit breaker QF1 is fully tripped, the short-circuit fault current all flows through the second fuse FU2, and the second fuse FU2 interrupts the short-circuit current. The overvoltage generated by cutting off the cut-off current is protected by the overvoltage limiter F.

[0053] When the generator-transformer circuit is operating normally, the monitoring device F2 monitors the internal operating conditions of the generator G (phase-to-phase, turn-to-turn windings of the generator, and stator and rotor conditions), and sends the monitored conditions to the control device F1. Once the control device F1 determines that an abnormal condition of the generator is detected, the control device F1 will issue a closing command to drive the second circuit breaker QF2 with a high-voltage load switch to close quickly, and the control device F1 will issue a tripping command to drive the first circuit breaker QF1 to trip, thereby realizing early prediction and processing and performing maintenance and repair of abnormal conditions to prevent the generator from being damaged.

[0054] When a fault occurs in the generator-transformer circuit and it operates out of step, through the backup protection setting of the first fuse FU1, it is prevented that the first circuit breaker QF1 opens the short-circuit current of the circuit before being broken down due to overvoltage.

[0055] Although the preferred embodiments of the present invention have been described in detail above, it should be clearly understood that various changes and modifications can be made to the present invention for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high-voltage fast shunt device for a generator set, configured to cooperate with a loop formed by a generator (G) and a transformer (TR), the transformer (TR) having a low-voltage side and a high-voltage side, the transformer (TR) being configured to be connected to a power grid system; characterized in that, The high-voltage fast shunt device for the generator set includes: A first transient current transformer (TA1), configured to be connected to the generator (G) to detect the cut-off current signal at the generator (G); A first fuse (FU1), whose first end is connected to the voltage output terminal of the generator (G) by connecting a second transient current transformer (TA2) in series; wherein, the second transient current transformer (TA2) is configured to detect the cut-off current signal in the circuit where it is located; A first circuit breaker (QF1), whose first end is connected to the second end of the first fuse (FU1), and the second end of the first circuit breaker (QF1) is connected to the low-voltage side of the transformer (TR) by connecting a third transient current transformer (TA3) in series, and the high-voltage side of the transformer (TR) is connected to the power grid system; wherein, the third transient current transformer (TA3) is configured to detect the cut-off current signal in the circuit where it is located; A second circuit breaker (QF2), whose first end is connected to the first end of the first fuse (FU1); A second fuse (FU2), whose first end is connected to the second end of the second circuit breaker (QF2), and the second end of the second fuse (FU2) is connected to the second end of the first circuit breaker (QF1); An overvoltage limiter (F), whose first end is connected to the first end of the first fuse (FU1), and the second end of the overvoltage limiter (F) is connected to the second end of the first circuit breaker (QF1); A monitoring device (F2), configured to monitor the internal operating conditions of the generator (G); A control device (F1), connected to the first transient current transformer (TA1), the second transient current transformer (TA2), the third transient current transformer (TA3) and the monitoring device (F2) respectively, and according to the signals sent by each transient current transformer, to drive the first circuit breaker (QF1) to trip and the second circuit breaker (QF2) to close when a short-circuit fault occurs in the loop formed by the generator and the transformer.

2. The high-voltage fast shunt device for a generator set according to claim 1, wherein The second circuit breaker (QF2) is a high-voltage load switch.

3. The high-voltage fast shunt device for a generator set according to claim 1, characterized in that, The internal operating conditions of the generator (G) include the phase conditions of the generator, the turn-to-turn winding conditions, the stator conditions and the rotor conditions.

4. The high-voltage fast shunt device for a generator set according to claim 3, wherein, The monitoring device (F2) is configured to be arranged inside the generator.

5. The high-voltage fast shunt device for a generator set according to any one of claims 1 to 4, characterized in that, The control device (F1) drives the first circuit breaker (QF1) to trip and the second circuit breaker (QF2) to close according to the signal sent by the monitoring device (F2) when the internal operating conditions of the generator (G) are abnormal.

6. A power generation system, comprising a generator (G) and a transformer (TR), the generator (G) and the transformer (TR) forming a loop, the transformer (TR) having a low voltage side and a high voltage side, the transformer (TR) being configured to be connected to a power grid system; characterized in that, The high-voltage fast shunt device for the generator set according to any one of claims 1 to 5 is applied.

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