CN106130014A - A kind of anti-error power-supply system based on high resistance grounding - Google Patents

Abstract

The invention discloses an anti-malfunction power supply system based on high-resistance grounding, which includes an isolation transformer and an anti-malfunction power supply, and also includes a high-resistance grounding device connected to the output end of the live wire and the output end of the ground wire, which includes: a grounding switch plate, the first One end is connected to the ground wire output end, the second end is connected to the live wire output end, and the third end is connected to the first end of the first resistor and the first end of the second resistor. The second end of the first resistor is connected to the first end of the fourth resistor, the second end of the second resistor is connected to the first end of the third resistor, the second end of the second resistor and the second end of the fourth resistor are grounded . When a terminal of the live wire is grounded, an abnormal signal will be generated at the ground point where the second terminal of the second resistor and the second terminal of the fourth resistor are located. When there is no grounding, it is convenient to realize the fault inspection of the anti-malfunction power supply system, and ensure that the potential of the anti-malfunction power supply system is limited to the normal range, thereby ensuring the safety in the operation detection of the anti-malfunction power supply system.

Description

An Anti-malfunction Power Supply System Based on High Resistance Grounding

technical field

The invention relates to the field of electric power technology, in particular to an anti-malfunction power supply system based on high-resistance grounding.

Background technique

When operating primary equipment in a substation, in order to ensure the safety of people and equipment, the requirements of the "five preventions" must be met: anti-mis-opening and closing the circuit breaker, anti-load pulling and closing the isolation knife switch, anti-charged closing and grounding knife switch, anti- Equipped with a ground wire and a circuit breaker to prevent mistaken entry into the electrified interval. The anti-malfunction power supply system of a traditional substation is generally composed of an electromagnetic lock, a live display and various auxiliary contacts. The wiring principle is shown in Figure 1. FIG. 1 is a circuit diagram of an anti-malfunction power supply system adopted in the prior art. The anti-malfunction power supply of the anti-malfunction power supply system generally adopts an ungrounded 220V power supply through an isolation transformer, as shown in the left half of Figure 1.

The traditional anti-malfunction power supply system consists of grounded 220V AC power supply, 220V/220V isolation transformer 10, anti-malfunction power supply FWA1-FWN1, FWA2-FWN2, FWA3-FWN3, FWA4-FWN5 and corresponding fuses (circuit breakers). Fig. 2 is a circuit diagram of the 110kV incoming line of the substation and the anti-misoperation part of the high voltage side of the main transformer in the prior art. The anti-mistake power supply is isolated by an isolation transformer to form an ungrounded system. Its main purpose is to prevent the outdoor equipment from short-circuiting after being grounded, and even cause false opening of the anti-mistake blocking. After the isolation transformer, the anti-malfunction power supply can be isolated from the AC system of the substation, thus ensuring the independence and reliability of the anti-malfunction circuit.

The problems of the traditional ungrounded anti-malfunction power supply system include:

First of all, it is difficult to check the outdoor equipment nodes: the ungrounded error-proof power supply system has no ground reference point, so a reference FWN or FWA is required when checking the error-proof circuit. However, due to the lack of FWN or FWA, it is difficult to check whether the outdoor equipment contacts shown by G1 and G3 in Figure 2 are normal.

Secondly, the rectification electronic circuit is easily damaged: the ground potential of the ungrounded anti-malfunction power system depends on factors such as the ground capacitance of the anti-malfunction circuit, so its ground potential may be much higher than 220V. Fig. 3 is a circuit diagram of a 10kV capacitor bank anti-misoperation blocking circuit in the prior art. Among them, the electronic rectifier bridge Qo-Yo used for locking the operating mechanism in the circuit breaker has a heat sink grounded, and the floating high potential of the anti-malfunction power supply can easily break down the Qo-Yo rectifier bridge to the ground.

Finally, it is impossible to detect one or more points of grounding through the equipment: when one or more points of the traditional anti-misoperation power supply system is grounded, it cannot pass the equipment detection, and when two or more points are grounded, it will cause abnormalities in the anti-misoperation circuit.

To sum up, the ungrounded anti-malfunction power supply system in the prior art cannot guarantee the safety of the operation process because it cannot detect whether there is a ground signal in the system when performing related operations.

It can be seen that how to realize the detection of the grounding signal of the anti-malfunction power supply system is an urgent problem to be solved by those skilled in the art.

Contents of the invention

The purpose of the present invention is to provide an anti-malfunction power supply system based on high-resistance grounding, which is used to realize the inspection of the anti-malfunction power supply system and prevent damage to electronic components.

In order to solve the above technical problems, the present invention provides a high-resistance grounding-based anti-malfunction power supply system, including an isolation transformer connected to the power supply, an anti-malfunction power supply connected to the live wire output end and the ground wire output end of the isolation transformer, and including a high-resistance grounding device connected to the live wire output terminal and the ground wire output terminal;

The high-resistance grounding device includes: a ground switching pressure plate, the first end of the ground switching pressure plate is connected to the ground wire output end, the second end of the ground switching pressure plate is connected to the live wire output end, and the ground The third terminal of the switch plate is connected to the first terminal of the first resistor and the first terminal of the second resistor, the second terminal of the first resistor is connected to the first terminal of the fourth resistor, and the first terminal of the second resistor The two terminals are connected to the first terminal of the third resistor, and the second terminal of the second resistor and the second terminal of the fourth resistor are grounded.

Preferably, a first fuse and a second fuse are also included, the first end of the ground switching pressure plate is connected to the ground wire output terminal through the first fuse, and the second end of the ground switching pressure plate is connected through the The second fuse is connected to the fire wire output terminal.

Preferably, it also includes a ground alarm relay and an alarm device, the second end of the second resistor and the second end of the fourth resistor are grounded through the coil of the ground alarm relay, the alarm device is connected to the ground alarm The switch of the relay is connected, and an alarm prompts when the switch is closed.

Preferably, the ground alarm relay is an AC voltage relay.

Preferably, the warning device includes a buzzer that turns on when the switch is closed.

Preferably, the warning device further includes a flashing light that turns on when the switch is closed.

The anti-malfunction power supply system based on high-resistance grounding provided by the present invention includes a high-resistance grounding device. During normal operation, the grounding switching platen is switched to the ground wire side, and the ground wire is grounded through a high resistance (first resistance-fourth resistance) . When a terminal of the live wire is grounded, an abnormal signal will be generated at the ground point where the second terminal of the second resistor and the second terminal of the fourth resistor are located. When there is no grounding, it is convenient to realize the fault inspection of the anti-malfunction power supply system, and ensure that the potential of the anti-malfunction power supply system is limited to the normal range. When anti-misoperation is required, switch the ground switching pressure plate to the live wire side to check whether there is a ground signal on the ground wire side, and then switch the ground switching pressure plate to the live wire side, and then check the operation of the anti-misoperation power supply system after checking that there is no ground signal. Therefore, the safety in the operation detection of the anti-malfunction power supply system is ensured.

Description of drawings

In order to illustrate the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. As far as people are concerned, other drawings can also be obtained based on these drawings on the premise of not paying creative work.

Fig. 1 is the circuit diagram of the anti-malfunction power supply system that prior art adopts;

Fig. 2 is a circuit diagram of the 110kV incoming line of the substation and the anti-misoperation part of the high voltage side of the main transformer in the prior art;

Fig. 3 is a circuit diagram of a 10kV capacitor bank anti-misoperation blocking circuit in the prior art;

Fig. 4 is the circuit diagram of a kind of anti-malfunction power supply system based on high resistance grounding provided by the present invention;

Fig. 5 is the circuit diagram of another kind of anti-malfunction power supply system based on high resistance grounding provided by the present invention;

Fig. 6 is a practical application circuit diagram of a high-resistance grounding device provided by the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The core of the invention is to provide an anti-malfunction power supply system based on high-resistance grounding.

In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 4 is a circuit diagram of an anti-malfunction power supply system based on high-resistance grounding provided by the present invention. As shown in Figure 4, the anti-malfunction power supply system based on high resistance grounding includes an isolation transformer 10 connected to the power supply, an anti-malfunction power supply FWA1-FWN1, FWA2- FWN2, FWA3-FWN3, FWA4-FWN5. It also includes a high-resistance grounding device 11 connected to the fire wire output terminal FWA and the ground wire output terminal FWN;

The high-resistance grounding device 11 includes: a ground switching pressure plate QP, the first end of the ground switching pressure plate QP is connected to the ground wire output terminal FWN, the second end of the ground switching pressure plate QP is connected to the live wire output terminal FWA, and the third end of the ground switching pressure plate QP end is connected with the first end of the first resistor R1 and the first end of the second resistor R2, the second end of the first resistor R1 is connected with the first end of the fourth resistor R4, and the second end of the second resistor R2 is connected with the first end of the second resistor R2. The first end of the third resistor R3 is connected, the second end of the second resistor R2 and the second end of the fourth resistor R4 are grounded.

In a specific implementation, the high-resistance grounding device 11 provided by the present invention is provided on the loops of the anti-malfunction power supplies FWA1-FWN1, FWA2-FWN2, FWA3-FWN3, and FWA4-FWN5.

FIG. 5 is a circuit diagram of another anti-malfunction power supply system based on high-resistance grounding provided by the present invention. As shown in Figure 5, it also includes a first fuse F1 and a second fuse F2,

The first end of the ground switching pressure plate QP is connected to the ground wire output terminal FWN through the first fuse F1, and the second end of the ground switching pressure plate QP is connected to the live wire output terminal FWA through the second fuse F2.

On the basis of the above embodiment, it also includes a grounding alarm relay J1 and an alarm device 12, the second end of the second resistor R2 and the second end of the fourth resistor R4 are grounded through the coil of the grounding alarm relay J1, and the alarm device 12 is connected to the ground The switch K1 of the alarm relay J1 is connected, and an alarm prompts when the switch K1 is closed.

In a specific implementation, the alarm device 12 includes a buzzer that is turned on when the switch is closed. In another embodiment, the warning device 12 also includes a flashing light that turns on when the switch is closed.

It can be understood that there are many ways to select the alarm device 12 , as long as the switch K1 is closed, the alarm can be prompted, and it is not limited to the above two implementation modes.

The selection of the parameters of the high resistance grounding device 11 provided above will be described in detail below. In the anti-malfunction power supply system based on high-resistance grounding, it is necessary to select the grounding resistance. The selection principles are:

1. The loop formed by the grounding resistance and the abnormal grounding point should not lead to the failure of the error prevention loop.

2. The power passing through the grounding resistance should meet the long-term operation requirements under full voltage, and the resistance will not be damaged when any point in the anti-malfunction power circuit is grounded.

3. When the high-resistance grounding device is grounded at a certain terminal point, when the high-resistance grounding device is too small to form a loop with FWN, the DSD electromagnetic lock on the loop will be accidentally opened. false opening.

Fig. 6 is a practical application circuit diagram of a high-resistance grounding device provided by the present invention. As shown in Figure 6, when the high-resistance grounding device 11 is grounded at the terminal 891:

Select the grounding resistance value according to principle 1: Each branch of the anti-malfunction circuit generally has an electromagnetic lock DSD with a resistance value of 2kΩ, and its minimum possible operating voltage is calculated as 20% of the rated voltage. After taking into account the margin requirements, the minimum possible action voltage of the electromagnetic lock DSD is limited to a level lower than 10% of the rated voltage, which should be able to reliably prevent the electromagnetic lock from malfunctioning and opening, so the total value of resistors R1-R4 connected in series and in parallel The resistor RE is:

$\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; \%</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 20</span>}\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; \&Omega;</span>}$

When the grounding resistance RE and the electromagnetic lock DSD are connected in series to the anti-malfunction power supply system, the resistance of the grounding resistance is 20kΩ-2kΩ=18kΩ. To ensure reliability, the actual value is selected as 20kΩ.

Since RE is two resistors R1-R4 connected in parallel and then connected in series, according to Ohm's law, when the resistance values of R1-R4 are the same, the resistance value of RE is the resistance value of a single resistor, but the power is 4 times that of a single resistor.

Select the power value of the grounding resistance according to principle 2: in extreme cases, the grounding resistance RE and the AC voltage type grounding detection relay bear the full voltage of the anti-malfunction power supply, then calculate the power of the grounding resistance RE and the grounding alarm relay J1 as:

The capacity of RE is 4 times the capacity of a single resistor (R1-R4), so the power converted to each 20kΩ resistor (R1-R4) is 0.5W, and it is regarded as 1W after considering the margin, then the power of the ground alarm relay J1 is : P _relay =20 ² /(2kΩ)=0.2W.

Considering the gap between the theoretical value and the actual value, in a specific implementation, the power of the grounding alarm relay J1 is selected to be greater than 1W.

Selection of Action Voltage for Grounding Alarm Relay

In the specific implementation, the grounding alarm relay J1 adopts an AC voltage relay. Assume that the impedance of the grounding alarming relay J1 is 2kΩ, and the operating voltage range is 5-20V. The grounding relay J1 bears the full voltage of the anti-malfunction power supply, and the divided voltage value of the grounding alarm relay J1 is:

$\frac{\mathrm{<span\; class="notranslate">\; 220</span>}\mathrm{<span\; class="notranslate">\; V</span>}}{\mathrm{<span\; class="notranslate">\; twenty\; two</span>}\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; \&Omega;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 20</span>}\mathrm{<span\; class="notranslate">\; V</span>}$

Therefore, the grounding alarm relay J1 selects an AC voltage relay with a rated voltage of 48V;

When the grounding resistance Re is 20kΩ, the total resistance is 20kΩ+22k=42kΩ, then the divided voltage on the grounding alarm relay J1 is:

$\frac{\mathrm{<span\; class="notranslate">\; 220</span>}\mathrm{<span\; class="notranslate">\; V</span>}}{\mathrm{<span\; class="notranslate">\; 42</span>}\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 10.5</span>}\mathrm{<span\; class="notranslate">\; V</span>}$

To sum up, in order to ensure the sensitivity, it is generally set to 10V, and it can reliably alarm when the grounding resistance is less than 20kΩ.

The principle of use of the high-resistance grounding device provided by the present invention is:

During normal operation, switch QP to the ACN side, and ground FWN through a high resistance (R1-R4). When FWA is grounded through a grounding resistance less than 20kΩ, it will cause the alarm relay J1 to act and output an alarm signal.

When there is no grounding, it is convenient to realize the fault detection of the anti-mistake loop, and ensure that the potential of the anti-mistake loop is limited to the normal range. When anti-misoperation is required, switch QP to ACA to detect whether there is FWN grounding, then switch QP to ACN, and then perform operation detection of the anti-misoperation loop after detecting that there is no grounding signal.

The anti-malfunction power supply system based on high-resistance grounding provided by the present invention includes a high-resistance grounding device. During normal operation, the grounding switching platen is switched to the ground wire side, and the ground wire is grounded through the high resistance (first resistance-fourth resistance). When a terminal of the live wire is grounded, an abnormal signal will be generated at the ground point where the second terminal of the second resistor and the second terminal of the fourth resistor are located. When there is no grounding, it is convenient to realize the fault inspection of the anti-malfunction power supply system, and ensure that the potential of the anti-malfunction power supply system is limited to the normal range. When anti-misoperation is required, switch the ground switching pressure plate to the live wire side to check whether there is a ground signal on the ground wire side, and then switch the ground switching pressure plate to the live wire side, and then check the operation of the anti-misoperation power supply system after checking that there is no ground signal. Therefore, the safety in the operation detection of the anti-malfunction power supply system is ensured.

The above is a detailed introduction to the anti-malfunction power supply system based on high resistance grounding provided by the present invention. Each embodiment in the description is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for the related part, please refer to the description of the method part. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Professionals can further realize that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software or a combination of the two. In order to clearly illustrate the possible For interchangeability, in the above description, the composition and steps of each example have been generally described according to their functions. Whether these functions are executed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be regarded as exceeding the scope of the present invention.

The steps of the methods or algorithms described in connection with the embodiments disclosed herein may be directly implemented by hardware, software modules executed by a processor, or a combination of both. Software modules can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other Any other known storage medium.

Claims (6)

1. an anti-error power-supply system based on high resistance grounding, including the isolating transformer being connected with power supply, with described isolation The anti-error power supply that the fire wire output end of transformator and ground line output terminal connect, it is characterised in that also include exporting with described live wire The high resistance grounding device that end and described ground line output terminal connect；

Described high resistance grounding device includes: ground connection switching pressing plate, and the first end of described ground connection switching pressing plate is defeated with described ground wire Going out end to connect, the second end of described ground connection switching pressing plate is connected with described fire wire output end, the 3rd of described ground connection switching pressing plate End is connected with the first end of the first resistance and the first end of the second resistance, the of the second end of described first resistance and the 4th resistance One end connects, and the second end of described second resistance and the first end of the 3rd resistance connect, the second end of described second resistance and institute State the second end ground connection of the 4th resistance.

Anti-error power-supply system based on high resistance grounding the most according to claim 1, it is characterised in that also include that first melts Silk and the second fuse,

First end of described ground connection switching pressing plate is connected with described ground line output terminal by described first fuse, and described ground connection switches Second end of pressing plate is connected with described fire wire output end by described second fuse.

Anti-error power-supply system based on high resistance grounding the most according to claim 1 and 2, it is characterised in that also include connecing Ground alarm relay and alarm device, the second end of described second resistance and the second end of described 4th resistance are by described ground connection The coil ground connection of alarm relay, described alarm device is connected with the switch of described ground connection alarm relay, closes at described switch Alarm prompt in the case of conjunction.

Anti-error power-supply system based on high resistance grounding the most according to claim 3, it is characterised in that described ground connection alerts Relay is alternating voltage relay.

Anti-error power-supply system based on high resistance grounding the most according to claim 3, it is characterised in that described alarm device Connect in the case of described switch Guan Bi including buzzer.

Anti-error power-supply system based on high resistance grounding the most according to claim 4, it is characterised in that described alarm device Also include that flash lamp is connected in the case of described switch Guan Bi.