A method and system for detecting and protecting against high voltage direct current valve triggering anomalies

Abstract

The application discloses a high-voltage direct-current valve trigger abnormality detection protection method and system, and relates to the technical field of direct-current control protection. The method comprises the following steps: receiving first state information, second state information, third state information, fourth state information and fifth state information; switching the high-voltage direct-current power transmission system after continuously satisfying the first state information, the second state information, the third state information and the fifth state information for 200 ms; locking the first valve group after continuously satisfying the first state information, the second state information, the third state information, the fourth state information and the fifth state information for 350 ms; and locking the second valve group after continuously satisfying the first state information, the second state information, the third state information and the fifth state information for 500 ms. The application can improve the risk identification and resistance of the direct-current control protection system to abnormal trigger abnormality conditions of the valve group.

Description

Technical Field

[0001] This invention relates to the field of DC control and protection technology, specifically to a method and system for detecting and protecting high-voltage DC valve triggering anomalies. Background Technology

[0002] Valve triggering is a critical control function of high-voltage direct current (HVDC) transmission systems. Abnormal valve control can lead to malfunctions in the HVDC system, such as valve non-conduction and commutation failure, severely impacting the safe and stable operation of the HVDC system and the power grid. For example, on June 9, 2022, an abnormal pulse triggering occurred in the low-end valve group of pole 1 at the Kunbei UHVDC multi-terminal station. Due to the persistent abnormality, a continuous zero current appeared at the low end of pole 1, causing the transmission power at the low end of pole 1 to drop from 2000MW to 0MW for an extended period. Because the control and protection system failed to detect the DC triggering abnormality and did not promptly lock the faulty valve group, the low-end valve group of pole 1 remained in a zero-power state for an extended period, severely affecting the safe and stable operation of the HVDC system and the power grid. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method and system for detecting and protecting high-voltage DC valve triggering anomalies, thereby improving the risk identification and mitigation capabilities of DC control protection systems against abnormal valve group triggering conditions.

[0004] To achieve the above objectives, the present invention can adopt the following technical solutions:

[0005] A method for detecting and protecting high-voltage DC valve triggering anomalies, used in a DC control protection system to detect faults in a valve assembly, includes the following steps:

[0006] Receive the first status information, the second status information, the third status information, the fourth status information, and the fifth status information;

[0007] The high-voltage direct current transmission system is switched after continuously satisfying the first state information, the second state information, the third state information, and the fifth state information and delaying for 200ms.

[0008] The first valve group is locked after continuously satisfying the first, second, third, fourth, and fifth state information and after a delay of 350ms.

[0009] The second valve group is locked after the first state information, the second state information, the third state information, and the fifth state information are continuously satisfied and a delay of 500ms is applied.

[0010] The first status information is the operating mode of the high-voltage direct current transmission system; the second status information is the voltage status of the high-voltage alternating current transmission system; the third status information is that the current of the high-voltage direct current transmission system is lower than a set value; the fourth status information is the DC voltage characteristics of the high-voltage direct current transmission system; and the fifth status information is that the angle command is lower than a set value.

[0011] The high-voltage DC valve triggering abnormal detection and protection method described above is further described in the following specific operating mode of the high-voltage DC transmission system: the high-voltage DC transmission system is operating in a hybrid DC mode and is in non-OLT operation mode, and communication is maintained normally.

[0012] In the above-described high-voltage DC valve triggering abnormal detection and protection method, the voltage state of the high-voltage AC transmission system is further defined as follows: the three-phase AC voltage is continuously greater than 0.9 pu and exceeds 1 second.

[0013] In the above-described high-voltage DC valve triggering abnormal detection and protection method, the current of the high-voltage DC transmission system being lower than the set value is specifically: Max(IDLN, IDCN) < 100A.

[0014] The high-voltage DC valve triggering abnormal detection and protection method described above is further described in the following ways: the DC voltage characteristics of the high-voltage DC transmission system are as follows: for a single valve group, there is no DC voltage condition, which is always met; for a double valve group, there is a valve group imbalance condition: (voltage difference between this valve group and the other valve group) > 0.1pu = 80kV.

[0015] In the high-voltage DC valve triggering abnormality detection and protection method described above, the angle command being lower than the set value specifically means: the angle command continuously being lower than 8°.

[0016] A high-voltage DC valve triggering anomaly detection and protection system, installed in a DC control and protection system to handle valve group fault detection, includes: a processor and an actuator.

[0017] The processor is used to receive first status information, second status information, third status information, fourth status information and fifth status information;

[0018] When the first state information, the second state information, the third state information, and the fifth state information are continuously satisfied and a delay of 200ms is applied, the high-voltage direct current transmission system is switched via the actuator.

[0019] When the first state information, the second state information, the third state information, the fourth state information, and the fifth state information are continuously satisfied and a delay of 350ms is applied, the first valve group is locked by the actuator.

[0020] When the first state information, the second state information, the third state information, and the fifth state information are continuously satisfied and a delay of 500ms is applied, the second valve group is locked by the actuator.

[0021] The first status information is the operating mode of the high-voltage direct current transmission system; the second status information is the voltage status of the high-voltage alternating current transmission system; the third status information is that the current of the high-voltage direct current transmission system is lower than a set value; the fourth status information is the DC voltage characteristics of the high-voltage direct current transmission system; and the fifth status information is that the angle command is lower than a set value.

[0022] As described above, the high-voltage DC valve triggering abnormal detection and protection system further specifies that the high-voltage DC transmission system operates in a hybrid DC mode and is in non-OLT operation mode, while communication remains normal.

[0023] As described above, the voltage state of the high-voltage AC transmission system is further defined as follows: the three-phase AC voltage is continuously greater than 0.9 pu and exceeds 1 second; the current of the high-voltage DC transmission system is lower than the set value as follows: Max(IDLN, IDCN) < 100A.

[0024] As described above, the DC voltage characteristics of the high-voltage DC transmission system are as follows: for a single valve group, there is no DC voltage condition, which is always met; for a dual valve group, there is a valve group imbalance condition: (voltage difference between this valve group and the other valve group) > 0.1pu = 80kV; the angle command being lower than the set value specifically means that the angle command is continuously lower than 8°.

[0025] Compared with the prior art, the beneficial effects of this invention are as follows: This invention can be configured in the rectifier station valve group control CCP host. Under the premise of meeting the operation requirements of the high voltage DC transmission system and without affecting the existing control and protection functions, this invention can reliably lock the valve group when a similar fault occurs on site, while avoiding accidental operation. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 The present invention provides a logic diagram of the high-voltage DC valve triggering abnormality detection and protection method and system. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0029] Example:

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, in the embodiments of this invention are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] See Figure 1 The basic principle of this invention is to meet the requirements of the system operation mode, and to reliably lock the valve group in the event of a similar fault on site without affecting the existing control and protection functions, while avoiding accidental operation.

[0032] Functional configuration: Rectifier station valve group control CCP main unit.

[0033] The following functional logic criteria are adopted:

[0034] 1. Hybrid DC operation mode: The DC system is operating in hybrid DC mode (delay 5s), and is not in OLT operation mode, and communication is normal;

[0035] 2. AC system voltage is normal: all three-phase AC voltages are continuously greater than 0.9 pu and last for more than 1 second;

[0036] 3. Low DC current: Max(IDLN, IDCN) < 100A;

[0037] 4. DC voltage characteristics: For a single valve group, there is no DC voltage condition, which is always met; for a dual valve group, there is a valve group imbalance condition: (voltage difference between this valve group and the other valve group) > 0.1pu = 80kV (64kV for step-down operation);

[0038] 5. Low Angle Command: Angle commands remain below 8°.

[0039] The low-current blocking logic output of this invention includes one switching section and two tripping sections, as shown in the simplified logic diagram below. Figure 1 As shown.

[0040] 1) Switching segment: Continuously satisfy ①, ②, ③, and ⑤, and switch the system after a 200ms delay;

[0041] 2) Trip Stage I: Continuously satisfy ①, ②, ③, ④, and ⑤, and lock the valve group after a 350ms delay;

[0042] 3) Trip Stage II: Continuously satisfy ①, ②, ③, and ⑤, and lock the valve group after a 500ms delay.

[0043] 4) Reduce the DC voltage on the inverter side: continuously satisfy ①, ②, ③, and ⑤, with a delay of 80ms;

[0044] 5) Increase the trigger angle: continuously satisfy ①, ②, ③, and ⑤, with a delay of 195ms.

[0045] Based on the above processing logic, this invention provides a high-voltage DC valve triggering anomaly detection and protection method for use in DC control and protection systems to detect valve group faults, comprising the following steps:

[0046] Receive the first status information, the second status information, the third status information, the fourth status information, and the fifth status information;

[0047] The high-voltage direct current transmission system is switched after continuously satisfying the first state information, the second state information, the third state information, and the fifth state information and delaying for 200ms.

[0048] The first valve group is locked after continuously satisfying the first, second, third, fourth, and fifth state information and after a delay of 350ms.

[0049] The second valve group is locked after the first state information, the second state information, the third state information, and the fifth state information are continuously satisfied and a delay of 500ms is applied.

[0050] The first status information is the operating mode of the high-voltage direct current transmission system; the second status information is the voltage status of the high-voltage alternating current transmission system; the third status information is that the current of the high-voltage direct current transmission system is lower than a set value; the fourth status information is the DC voltage characteristics of the high-voltage direct current transmission system; and the fifth status information is that the angle command is lower than a set value.

[0051] Furthermore, in some embodiments, the high-voltage direct current transmission system operates in a hybrid DC mode and is in a non-OLT operation mode, while communication remains normal.

[0052] Furthermore, in some embodiments, the voltage state of the high-voltage AC transmission system is specifically as follows: the three-phase AC voltage is continuously greater than 0.9 pu and exceeds 1 second.

[0053] Furthermore, in some embodiments, the current of the high-voltage direct current transmission system is lower than a set value specifically: Max(IDLN, IDCN) < 100A.

[0054] Furthermore, in some embodiments, the DC voltage characteristics of the high-voltage direct current transmission system are specifically as follows: for a single valve group, there is no DC voltage condition, which is always satisfied; for a dual valve group, there is a valve group imbalance condition: (voltage difference between this valve group and the other valve group) > 0.1pu = 80kV.

[0055] Furthermore, in some embodiments, the angle command being lower than a set value specifically means that the angle command remains below 8°.

[0056] Based on the same inventive concept, embodiments of the present invention also provide a high-voltage DC valve triggering anomaly detection and protection system, which is installed in a DC control protection system to address valve group fault detection, and includes: a processor and an actuator.

[0057] The processor is used to receive first status information, second status information, third status information, fourth status information and fifth status information;

[0058] When the first state information, the second state information, the third state information, and the fifth state information are continuously satisfied and a delay of 200ms is applied, the high-voltage direct current transmission system is switched via the actuator.

[0059] When the first state information, the second state information, the third state information, the fourth state information, and the fifth state information are continuously satisfied and a delay of 350ms is applied, the first valve group is locked by the actuator.

[0060] When the first state information, the second state information, the third state information, and the fifth state information are continuously satisfied and a delay of 500ms is applied, the second valve group is locked by the actuator.

[0061] The first status information is the operating mode of the high-voltage direct current transmission system; the second status information is the voltage status of the high-voltage alternating current transmission system; the third status information is that the current of the high-voltage direct current transmission system is lower than a set value; the fourth status information is the DC voltage characteristics of the high-voltage direct current transmission system; and the fifth status information is that the angle command is lower than a set value.

[0062] Furthermore, in some embodiments, the high-voltage direct current transmission system operates in a hybrid DC mode and is in a non-OLT operation mode, while communication remains normal.

[0063] Furthermore, in some embodiments, the voltage state of the high-voltage AC transmission system is specifically: the three-phase AC voltage is continuously greater than 0.9 pu and exceeds 1 s; the current of the high-voltage DC transmission system is lower than the set value specifically: Max(IDLN, IDCN) < 100A.

[0064] Furthermore, in some embodiments, the DC voltage characteristics of the high-voltage direct current transmission system are specifically as follows: for a single valve group, there is no DC voltage condition, which is always met; for a dual valve group, there is a valve group imbalance condition: (this valve group - the other valve group) voltage difference > 0.1pu = 80kV; the angle command being lower than the set value specifically means: the angle command is continuously lower than 8°.

[0065] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0066] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for detecting abnormality of a high voltage direct current valve trigger for detecting a failure of a valve group by a direct current control protection system, characterized by, Including the following steps: Receive the first status information, the second status information, the third status information, the fourth status information, and the fifth status information; The high-voltage direct current transmission system is switched after continuously satisfying the first state information, the second state information, the third state information, and the fifth state information and delaying for 200ms. The first valve group is locked after continuously satisfying the first, second, third, fourth, and fifth state information and after a delay of 350ms. The second valve group is locked after the first state information, the second state information, the third state information, and the fifth state information are continuously satisfied and a delay of 500ms is applied. The first status information indicates that the high-voltage direct current (HVDC) transmission system is operating in a hybrid DC mode and in a non-OLT operation mode, while system communication remains normal. The second status information is determined by the condition that the three-phase AC voltage of the high-voltage AC transmission system is continuously greater than 0.9 pu for more than 1 second. The third status information indicates that the current of the HVDC transmission system is lower than a set value. The fourth status information indicates that the DC voltage of the HVDC transmission system meets the determination conditions of the corresponding valve group configuration, wherein there is no DC voltage determination condition for a single valve group, and the determination condition for a dual valve group is that the voltage difference between the valve group and the opposing valve group is greater than 0.1 pu = 80 kV. The fifth status information indicates that the angle command is lower than a set value.

2. The high-voltage DC valve triggering abnormality detection and protection method according to claim 1, characterized in that, The current of the high-voltage direct current transmission system is lower than the set value, specifically: Max(IDLN, IDCN) < 100A.

3. The HVDC valve triggering anomaly detection protection method of claim 1, wherein, Specifically, the angle command being lower than the set value means that the angle command remains below 8°.

4. A high voltage DC valve triggering abnormality detection protection system provided in a DC control protection system to cope with a failure detection of a valve group, characterized by, include: Processors and actuators The processor is used to receive first status information, second status information, third status information, fourth status information and fifth status information; When the first state information, the second state information, the third state information, and the fifth state information are continuously satisfied and a delay of 200ms is applied, the high-voltage direct current transmission system is switched via the actuator. When the first state information, the second state information, the third state information, the fourth state information, and the fifth state information are continuously satisfied and a delay of 350ms is applied, the first valve group is locked by the actuator. When the first state information, the second state information, the third state information, and the fifth state information are continuously satisfied and a delay of 500ms is applied, the second valve group is locked by the actuator. The first status information indicates that the high-voltage direct current (HVDC) transmission system is operating in a hybrid DC mode and in a non-OLT operation mode, while system communication remains normal. The second status information is determined by the condition that the three-phase AC voltage of the high-voltage AC transmission system is continuously greater than 0.9 pu for more than 1 second. The third status information indicates that the current of the HVDC transmission system is lower than a set value. The fourth status information indicates that the DC voltage of the HVDC transmission system meets the determination conditions of the corresponding valve group configuration, wherein there is no DC voltage determination condition for a single valve group, and the determination condition for a dual valve group is that the voltage difference between the valve group and the opposing valve group is greater than 0.1 pu = 80 kV. The fifth status information indicates that the angle command is lower than a set value.

5. The HVDC valve triggering anomaly detection protection system of claim 4, wherein, The current of the high-voltage direct current transmission system is lower than the set value, specifically: Max(IDLN, IDCN) < 100A.

6. The high voltage DC valve triggering anomaly detection protection system of claim 4, wherein, Specifically, the angle command being lower than the set value means that the angle command remains below 8°.

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