Anti-maloperation circuit of power secondary circuit

Abstract

The utility model discloses an anti-maloperation circuit of an electric power secondary circuit. The anti-maloperation circuit comprises a fourth resistor R1, a fifth resistor R2, a positive pole input end R +, a negative pole input end R-, a fifth capacitor C +, a sixth capacitor C-, a # 1 main transformer chamber and a # 52 chamber. The # 1 main transformer chamber comprises a switch K1 and a first distributed capacitor C1; the 52 small chamber comprises a relay and an anti-maloperation module which is arranged at two ends of a relay coil or two ends of an optocoupler input side and is formed by adding a resistance-capacitance element, and the relay is connected with the switch K1 and is used for switching a circuit state when the switch acts. When alternating current flows into a direct current system, alternating current flowing through a related relay (or an optical coupler) can be bypassed, and when direct current grounding occurs, the maloperation prevention module can bypass transient current generated by the distributed capacitor, so that maloperation of the related relay (or the optical coupler) is avoided; the effect of preventing protection maloperation and switch maloperation when alternating current enters the direct current system and the direct current system is grounded is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of power protection, in particular to a circuit for preventing malfunction of a power secondary circuit. Background Art

[0002] One of the most direct hazards of AC ingress into a DC system and DC system grounding is the potential for false tripping of relay protection devices, meaning they can erroneously trigger protection tripping when no fault has actually occurred in the primary equipment of the power system. Correct operation of relay protection devices is crucial to maintaining power system stability, and false tripping can lead to unnecessary power outages, threatening the safe operation and reliability of the power grid. Therefore, designing and implementing effective measures to prevent false tripping caused by AC ingress into the DC system and DC system grounding is crucial to ensuring the safe and stable operation of the power system.

[0003] Currently, various units can basically find the cause of tripping when analyzing accidents caused by AC leakage into the DC system and DC system grounding. In some cases, the accident process can be reproduced, but no simple and comprehensive solution is given. The response measures taken are limited to preventing operational errors during the work process and avoiding the recurrence of tripping caused by AC leakage into the DC system and DC system grounding. Utility Model Content

[0004] In order to overcome the problem of switch tripping caused by AC leaking into the DC system and DC system grounding that often occurs in existing substations, the utility model provides a power secondary circuit anti-false operation circuit, which can prevent the switch from false operation when AC leaks into the DC system and the DC system is grounded.

[0005] In order to achieve the above object, the utility model provides the following technical solutions: a power secondary circuit anti-malfunction circuit, the anti-malfunction circuit comprising a fourth resistor R1, a fifth resistor R2, a positive input terminal R+, a negative input terminal R-, a fifth capacitor C+, a sixth capacitor C-, a #1 main transformer chamber and a chamber 52;

[0006] The positive input terminal R+ and the negative input terminal R- are used to receive external signals or power;

[0007] The fourth resistor R1 and the fifth resistor R2 are connected to the positive input terminal R+ and the negative input terminal R- respectively;

[0008] The fifth capacitor C+ and the sixth capacitor C- are connected in parallel with the fourth resistor R1 and the fifth resistor R2 respectively;

[0009] The #1 main transformer compartment includes a switch K1 and a first distributed capacitor C1; the switch K1 is a double-contact switch for simultaneously controlling the on / off of the positive input terminal R+ and the negative input terminal R-;

[0010] The chamber 52 includes a relay and an anti-malfunction module composed of resistor and capacitor elements arranged at both ends of the relay coil or at both ends of the optocoupler input side. The relay is connected to the switch K1 and is used to switch the circuit state when the switch is actuated; the resistor and capacitor elements are resistor elements and capacitor elements, and the resistor element and the capacitor element are combined in series and parallel.

[0011] Furthermore, the #1 main transformer chamber is connected to the 52 chamber via a cable, and the cable is connected to a second distributed capacitor C2.

[0012] Furthermore, the resistance and capacitance elements are resistance elements and capacitance elements, and the resistance elements and capacitance elements are combined in series and parallel.

[0013] Furthermore, the capacitor element in the anti-maloperation module is a non-polar capacitor with a withstand voltage of more than 250V.

[0014] Furthermore, the anti-malfunction module includes a first resistor R N1 and a capacitor group, the capacitor group including a first capacitor C W1 and the second capacitor C W2 , the first capacitor C W1 and the second capacitor C W2 After connecting in series with the first resistor R N1 in parallel.

[0015] Furthermore, the anti-malfunction module includes a first resistor R N1 , the second resistor R N2 and a capacitor group, wherein the capacitor group includes two groups of capacitors, the first group of capacitors includes a first capacitor C W1 and the second capacitor C W2 , the second group of capacitors includes a third capacitor C W3 and the fourth capacitor C W4 , the first capacitor C W1 and the second capacitor C W2 In series, the third capacitor C W3 and the fourth capacitor C W4 In series, the first group of capacitors is connected in parallel with the second group of capacitors, and the first resistor R N1 and the second resistor R N2 After being connected in series, they are connected in parallel with the capacitor bank.

[0016] Furthermore, the anti-malfunction module includes a first resistor R N1 , the second resistor R N2 , the third resistor R N3 and a capacitor group, wherein the capacitor group includes two groups of capacitors, the first group of capacitors includes a first capacitor C W1 and the second capacitor C W2 , the second group of capacitors includes a third capacitor CW3 and the fourth capacitor C W4 , the first capacitor C W1 and the second capacitor C W2 In series, the third capacitor C W3 and the fourth capacitor C W4 The first group of capacitors is connected in series with the second group of capacitors in parallel, and the second resistor R N2 and the third resistor R N3 After being connected in series, it is connected in parallel with the capacitor bank and then connected to the first resistor R N1 Series connection.

[0017] Furthermore, the anti-malfunction module includes a first resistor R N1 , the second resistor R N2 , the third resistor R N3 and a capacitor group, the capacitor group including a first capacitor C W1 and the second capacitor C W2 , the first capacitor C W1 With the second capacitor C W2 In parallel, the second resistor R N2 and the third resistor R N3 After being connected in series, it is connected in parallel with the capacitor bank and then connected to the first resistor R N1 Series connection.

[0018] In the above technical solution, the technical effects and advantages provided by the utility model are:

[0019] 1. When AC leaks into the DC system, the present invention can bypass the AC power flowing through the tripping relay. When DC grounding occurs, the anti-malfunction module can bypass the transient current of the distributed capacitor, so that the relevant relay (or optocoupler) does not malfunction, achieving the effect of preventing malfunction of the switch when AC leaks into the DC system and the DC system is grounded.

[0020] 2. The utility model can be directly installed at both ends of the trip relay (TJQ, TJR, TBJ and optocoupler input, etc.), and the installation does not require the switch to be powered off, so the installation is simple and convenient.

[0021] 3. When AC leaks into the DC system or DC grounding occurs, the circuit that directly trips via the long cable will not malfunction, thus avoiding accidents and improving the safety and reliability of the relay protection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0023] Figure 1 This is a schematic diagram of the installation and wiring of the anti-malfunction module of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of the anti-malfunction module preferably used in the embodiment of the utility model;

[0025] Figure 3 This is a TJR test waveform diagram when a DC grounding occurs in a control circuit without the utility model installed;

[0026] Figure 4 This is a TJR test waveform diagram when a DC ground occurs in the control circuit after the utility model is installed;

[0027] Figure 5 This is a TJR test waveform diagram when AC-DC crosstalk occurs in the control circuit without the utility model installed;

[0028] Figure 6 This is a TJR test waveform diagram when AC-DC crosstalk occurs in the control circuit after the utility model is installed. DETAILED DESCRIPTION

[0029] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0030] Example

[0031] like Figure 1 As shown, the power secondary circuit anti-malfunction circuit described in this embodiment includes a fourth resistor R1, a fifth resistor R2, a positive input terminal R+, a negative input terminal R-, a fifth capacitor C+, a sixth capacitor C-, a #1 main transformer chamber, and a chamber 52;

[0032] The positive input terminal R+ and the negative input terminal R- are used to receive external signals or power;

[0033] The fourth resistor R1 and the fifth resistor R2 are connected to the positive input terminal R+ and the negative input terminal R- respectively;

[0034] The fifth capacitor C+ and the sixth capacitor C− are connected in parallel with the fourth resistor R1 and the fifth resistor R2, respectively; the fifth capacitor C+ and the sixth capacitor C−, together with the fourth resistor R1 and the fifth resistor R2, form a low-pass filter network for suppressing common-mode and differential-mode noise;

[0035] The #1 main transformer compartment includes a switch K1 and a first distributed capacitor C1; the switch K1 is a double-contact switch for simultaneously controlling the on / off of the positive input terminal R+ and the negative input terminal R-; the first distributed capacitor C1 is used to suppress high-frequency interference and ensure signal symmetry;

[0036] Chamber 52 includes a relay and a misoperation prevention module consisting of resistors and capacitors (RCs) installed at both ends of the relay coil or at both ends of the optocoupler input. The relay is connected to switch K1 to switch the circuit state when the switch is actuated. The RCs are resistors and capacitors, which are combined in series and parallel. This series and parallel combination of the resistors and capacitors is designed based on the equivalent impedance range of actual application and implemented using hardware, thereby specifically selecting the most appropriate RC series and parallel combination.

[0037] This embodiment utilizes the relatively low impedance of equivalent resistive and capacitive elements within the system to suppress low-frequency or high-frequency interference from key components within the system. The anti-malfunction module, combined with the power system structure, can construct a filtering system using resistors, capacitors, and other components to influence the output of key components in the power system.

[0038] For devices that have not been put into operation or are planned to be put into operation in the future, the anti-malfunction circuit of this embodiment is integrated into the board of the device that has not been put into operation or is planned to be put into operation in the future after selecting components of different sizes but similar circuit parameters, so as to achieve the effect of adding the anti-malfunction function during the design stage of the device that has not been put into operation or is planned to be put into operation in the future.

[0039] The capacitor element in the anti-maloperation module is a non-polarized capacitor with a resistance power of no less than 5 watts, a capacitor voltage resistance of more than 250V, no capacitance decay within 20 years, and no breakdown due to high-voltage surge impact.

[0040] The anti-tampering module can be operated in an ambient temperature ranging from -50°C at the lowest to 70°C at the highest, and can be operated in an ambient humidity ranging from 10% to 90%.

[0041] In a preferred embodiment, Figure 2 As shown in (a), Figure 2 (a) is the anti-malfunction module V1, which includes a first resistor R N1 and a capacitor group, the capacitor group including a first capacitor C W1 and the second capacitor C W2 , the first capacitor C W1 and the second capacitor C W2 After connecting in series with the first resistor R N1 in parallel.

[0042] In a preferred embodiment, Figure 2 As shown in (b), Figure 2 (b) is the anti-malfunction module V2, which includes a first resistor R N1 , the second resistor R N2 and a capacitor group, wherein the capacitor group includes two groups of capacitors, the first group of capacitors includes a first capacitor C W1 and the second capacitor C W2 , the second group of capacitors includes a third capacitor C W3 and the fourth capacitor C W4 , the first capacitor C W1 and the second capacitor C W2 In series, the third capacitor C W3 and the fourth capacitor C W4 In series, the first group of capacitors is connected in parallel with the second group of capacitors, and the first resistor R N1 and the second resistor R N2 After being connected in series, they are connected in parallel with the capacitor bank.

[0043] In a preferred embodiment, Figure 2 As shown in (c), Figure 2 (c) is the anti-malfunction module V3, which includes a first resistor R N1 , the second resistor R N2 , the third resistor R N3 and a capacitor group, wherein the capacitor group includes two groups of capacitors, the first group of capacitors includes a first capacitor C W1 and the second capacitor C W2 , the second group of capacitors includes a third capacitor C W3 and the fourth capacitor C W4 , the first capacitor C W1 and the second capacitor C W2 In series, the third capacitor C W3 and the fourth capacitor C W4 The first group of capacitors is connected in series with the second group of capacitors in parallel, and the second resistor R N2 and the third resistor R N3 After being connected in series, it is connected in parallel with the capacitor bank and then connected to the first resistor R N1 Series connection.

[0044] In a preferred embodiment, Figure 2 As shown in (d), Figure 2 (d) is an anti-malfunction module V4, which includes a first resistor R N1 , the second resistor R N2 , the third resistor R N3 and a capacitor group, the capacitor group including a first capacitor C W1 and the second capacitor C W2, the first capacitor C W1 With the second capacitor C W2 In parallel, the second resistor R N2 and the third resistor R N3 After being connected in series, it is connected in parallel with the capacitor bank and then connected to the first resistor R N1 Series connection.

[0045] Figure 2 In the example, J1 is a terminal block. During installation, terminals D2 and D3 are short-circuited. The purpose of disconnecting terminals D2 and D3 is to confirm the integrity of the capacitors by measuring the capacitance at terminals D3 and D4. Measuring terminals D1 and D4 also confirms the integrity of the resistors, eliminating the need for a soldering iron and facilitating testing. The anti-tampering modules V1 and V2 do not isolate the resistors from the capacitors by disconnecting terminals D2 and D3. Therefore, capacitance cannot be directly measured and requires soldering the resistors before testing.

[0046] Figure 2 In the anti-malfunction module V3 and anti-malfunction module V4, R N1 It is a current-limiting resistor. Due to the large capacitance, the capacitor charging current is large when DC power is applied. If current limiting measures are not set, after the relay (or optocoupler) is installed with this module, the contacts used to start the relay in other protection devices and measurement and control devices will be subjected to a large current impact. The impact current will exceed the rated current of the starting relay contacts, which may easily cause contact erosion and lead to poor contact.

[0047] There is another innovation in the Anti-Misoperation Module V1, Anti-Misoperation Module V2 and Anti-Misoperation Module V3: if only a single capacitor is used, the filtering effect will be lost when the capacitor breaks down. The Anti-Misoperation Module V3 uses C W1 、C W2 、C W3 、C W4 The four capacitors are connected in series in two phases and then in parallel in two groups. When a single capacitor breaks down, the filtering effect is not reduced and the system will not be short-circuited. The resistor also has this problem, so R N2 、R N3 The two resistors are connected in series to prevent a single resistor from being short-circuited and causing the filtering function to fail.

[0048] The utility model is connected at both ends of the relay coil or the optical coupler input side ( Figure 1 The anti-malfunction module (FWD) is composed of the TJR relay and the appropriate resistor and capacitor components. When AC enters the DC system or the DC system is grounded, Figure 1The steady-state or transient AC current generated by the TJR relay is bypassed by the anti-malfunction module (FWD). Because the AC impedance of the anti-malfunction module (FWD) is much lower than the impedance of the long cable distributed capacitance C2, the steady-state or transient AC voltage generated when AC enters the DC system is primarily applied to distributed capacitance C2. The AC voltage drop across the TJR relay coil is low, preventing the TJR relay from operating. When K1 operates and trips normally, the DC power supply between the positive and negative poles of the DC bus is sufficiently high, and the charging time of the RC components of the anti-open-circuit module connected in parallel to the TJR relay coil is extremely short, without affecting the DC operating characteristics of the TJR relay. The utility model can also be added to other relay models (such as the TJQ relay in the operating box, non-electrical protection trip relays, and optocouplers) to achieve the same anti-malfunction effect.

[0049] like Figure 3-Figure 6 As shown, taking the TJR relay as an example, the following are the measured actions of the TJR relay when DC grounding and AC-DC crosstalk occur without and with the anti-malfunction module, respectively. Channel A of the oscilloscope is the voltage across the TJR relay coil, and channel B is the action of the action contact. Figure 3 Without the anti-malfunction module, the operating waveform when the DC system is grounded and the transient voltage on the TJR relay reaches the operating condition; Figure 4 In order to add the anti-malfunction module, the DC system is grounded, and the voltage waveform on the TJR relay coil occurs. It can be seen that the transient voltage is greatly reduced after adding the anti-malfunction module, and the relay does not operate; the action waveform when it does not operate is reached. Figure 5 Without the anti-malfunction module, the waveform of the TJR relay when AC enters the DC system is shown below: Figure 6 The voltage waveform across the TJR relay coil shows that the addition of the anti-malfunction module significantly reduces the current and voltage across the relay coil, preventing the relay from operating. Therefore, by adding appropriate RC components across the relay, the anti-malfunction module effectively prevents malfunctions caused by AC ingress into the DC system and grounding the DC system, effectively preventing malfunctions.

[0050] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of these 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 any one or more embodiments or examples.

[0051] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, numerous modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A circuit for preventing malfunction of a secondary power circuit, characterized in that: The anti-malfunction circuit includes a fourth resistor R1, a fifth resistor R2, a positive input terminal R+, a negative input terminal R-, a fifth capacitor C+, a sixth capacitor C-, a #1 main transformer chamber and a chamber 52; The positive input terminal R+ and the negative input terminal R- are used to receive external signals or power; The fourth resistor R1 and the fifth resistor R2 are connected to the positive input terminal R+ and the negative input terminal R- respectively; The fifth capacitor C+ and the sixth capacitor C- are connected in parallel with the fourth resistor R1 and the fifth resistor R2 respectively; The #1 main transformer compartment includes a switch K1 and a first distributed capacitor C1; the switch K1 is a double-contact switch for simultaneously controlling the on / off of the positive input terminal R+ and the negative input terminal R-; The chamber 52 includes a relay and an anti-malfunction module composed of resistance and capacitance elements added at both ends of the relay coil. The relay is connected to the switch K1 and is used to switch the circuit state when the switch is actuated. The resistance and capacitance elements are resistance elements and capacitance elements, and the resistance elements and capacitance elements are combined in series and parallel.

2. The power secondary circuit anti-malfunction circuit according to claim 1, characterized in that: The #1 main transformer chamber is connected to the 52 chamber via a cable, and the cable is connected to a second distributed capacitor C2.

3. The power secondary circuit anti-malfunction circuit according to claim 1, characterized in that: The capacitor element in the anti-malfunction module is a non-polarized capacitor with a withstand voltage of 250V or above.

4. The power secondary circuit anti-malfunction circuit according to claim 1, characterized in that: The anti-malfunction module includes a first resistor R N1 and a capacitor group, the capacitor group including a first capacitor C W1 and the second capacitor C W2 , the first capacitor C W1 and the second capacitor C W2 After connecting in series with the first resistor R N1 in parallel.

5. The power secondary circuit anti-malfunction circuit according to claim 1, characterized in that: The anti-malfunction module includes a first resistor R N1 , the second resistor R N2 and a capacitor group, wherein the capacitor group includes two groups of capacitors, the first group of capacitors includes a first capacitor C W1 and the second capacitor C W2 , the second group of capacitors includes a third capacitor C W3 and the fourth capacitor C W4 , the first capacitor C W1 and the second capacitor C W2 In series, the third capacitor C W3 and the fourth capacitor C W4 In series, the first group of capacitors is connected in parallel with the second group of capacitors, and the first resistor R N1 and the second resistor R N2 After being connected in series, they are connected in parallel with the capacitor bank.

6. The power secondary circuit anti-malfunction circuit according to claim 1, characterized in that: The anti-malfunction module includes a first resistor R N1 , the second resistor R N2 , the third resistor R N3 and a capacitor group, wherein the capacitor group includes two groups of capacitors, the first group of capacitors includes a first capacitor C W1 and the second capacitor C W2 , the second group of capacitors includes a third capacitor C W3 and the fourth capacitor C W4 , the first capacitor C W1 and the second capacitor C W2 In series, the third capacitor C W3 and the fourth capacitor C W4 The first group of capacitors is connected in series with the second group of capacitors in parallel, and the second resistor R N2 and the third resistor R N3 After being connected in series, it is connected in parallel with the capacitor bank and then connected to the first resistor R N1 Series connection.

7. The power secondary circuit anti-malfunction circuit according to claim 1, characterized in that: The anti-malfunction module includes a first resistor R N1 , the second resistor R N2 , the third resistor R N3 and a capacitor group, the capacitor group including a first capacitor C W1 and the second capacitor C W2 , the first capacitor C W1 With the second capacitor C W2 In parallel, the second resistor R N2 and the third resistor R N3 After being connected in series, it is connected in parallel with the capacitor bank and then connected to the first resistor R N1 Series connection.

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