Electric leakage alarm system capable of preventing false alarm
The leakage alarm system with a dual power supply circuit, zero-sequence current transformer, and dual power switch, addresses false alarms by maintaining balanced current flow, preventing false alarms and ensuring accurate leakage detection.
Patent Information
- Application Number
- CN202420365746.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-28
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2034-02-28
AI Technical Summary
Existing leakage alarm systems in warehouse power supply systems experience false alarms due to three-phase unbalanced current induced by a connected generator neutral line, causing unnecessary activation of fire-fighting equipment.
A leakage alarm system with a dual power supply circuit, a zero-sequence current transformer, and a contactor with a normally open state, and a dual power switch, which includes a contactor, and a dual power switch, which prevents false alarms by ensuring balanced current detection through a contactor with a normally open state, and a dual power switch, which prevents false alarms by maintaining a balanced current flow.
Prevents false alarms by maintaining balanced current detection and ensuring the prevention of false alarms, allowing the balanced current to zero, thereby preventing the three-phase unbalanced current from inducing false alarms, and ensuring accurate detection of actual leakage currents.
Smart Images
Figure CN222212910U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of warehouse electricity use, and particularly relates to a leakage alarm system for preventing false alarms. Background Art
[0002] In the power supply system of each large warehouse, there is a dual power switch. Fire-fighting electrical equipment such as emergency lighting, smoke exhaust fans, fire doors, and fire pumps are powered by the dual power switch. The main power of the dual power switch is the main power, and the backup power is the generator. During normal production, the main power is working and the generator is in a stopped backup state. Once a fire occurs, the main power is completely stopped and the generator is started. The dual power switch automatically switches to the generator power supply mode. The anti-leakage device is that whenever the live wire leaks, the leakage current will be sensed on the leakage alarm device. When the leakage current reaches 1 ampere, the alarm device sends an alarm signal.
[0003] However, in the early stage of the installation of the alarm device, there were alarm failures every day. After investigation, there was no leakage problem in the cables or electrical components. If there was a leakage problem, the alarm should always be sounded, not occasionally. It was finally determined that the cause of the false alarm was that the generator neutral line was connected to the mains neutral line, resulting in the shunting of the three-phase unbalanced current, which caused the induction current on the transformer. Utility Model Content
[0004] The purpose of the utility model is to solve the deficiencies of the above-mentioned technology and provide a leakage alarm system which can prevent false alarms.
[0005] To this end, the utility model provides a leakage alarm system for preventing false alarms, including a mains power supply and a backup power supply, wherein the mains power supply is connected to the backup power supply to form a dual power supply circuit; a current transformer and a dual power supply load circuit are connected in the dual power supply circuit, and the neutral lines connecting the mains power supply and the backup power supply are connected through the contacts of a contactor, and the coil of the contactor is connected between the live line and the neutral line of the backup power supply.
[0006] Furthermore, the mains power supply and the backup power supply are both three-phase four-wire systems, consisting of three live wires and one grounded neutral wire.
[0007] Furthermore, the mains power supply and the backup power supply are also provided with dual power switches.
[0008] Furthermore, the current transformer uses a zero-sequence current transformer.
[0009] Furthermore, the zero-sequence current transformer is also connected to a leakage monitoring instrument.
[0010] Furthermore, the backup power supply is an AC three-phase generator.
[0011] The utility model provides a leakage alarm system for preventing false alarms, which has the following beneficial effects:
[0012] By setting the contactor's contacts to be connected to the neutral line, the neutral line connecting the AC power supply and the backup power supply can be kept in a normally open state, preventing the three-phase unbalanced current from being shunted, causing induced current to be generated in the current transformer, and causing the alarm device to generate a false alarm.
[0013] By setting up AC power supply, backup power supply and dual power switch, the AC power supply can be disconnected in the event of a fire, and the engine can be used to generate electricity to supply the normal operation of fire-fighting electrical equipment such as emergency lighting and smoke exhaust fans. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is a circuit connection schematic diagram of the utility model. DETAILED DESCRIPTION
[0015] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments to help understand the content of the present invention. The methods used in the present invention are all conventional methods unless otherwise specified; the raw materials and devices used are all conventional commercial products unless otherwise specified.
[0016] like Figure 1 As shown, the utility model provides a leakage alarm system for preventing false alarms, including a mains power supply and a backup power supply, the mains power supply and the backup power supply are connected to form a dual power supply circuit. The mains power supply is a three-phase four-wire system, including three live wires La1, Lb1, Lc1 and a neutral wire Lo1. The backup power supply is a generator, and the output is also a three-phase four-wire system, including three live wires La2, Lb2, Lc2 and a neutral wire Lo2. A current transformer and a dual power load circuit are connected in the dual power supply circuit. In one embodiment, the current transformer uses a zero-sequence current transformer connected to a leakage monitoring instrument. A contactor JC is connected to the neutral line. In one embodiment, the coil of the contactor JC is connected between the live wire Lc2 and the neutral wire Lo2, and the contact of the contactor JC is connected between the neutral wire Lo1 and the neutral wire Lo2, which can make the neutral wire connected to the mains power supply and the backup power supply in a normally open state, preventing the three-phase unbalanced current from being shunted, resulting in an induced current on the current transformer.
[0017] In one implementation, the leakage monitoring instrument may use a smart power device model DH-CMS3NB produced by Zhejiang Dahua Technology Co., Ltd.
[0018] It should be noted that, using the principle of three-phase power supply balance, when there is no leakage in each electrical device, the three-phase unbalanced current will pass through the neutral line, and the neutral line current and the unbalanced current are in opposite directions, which just cancel each other out to zero. At this time, the current value detected by the zero-sequence current transformer is zero. Once the live wire leaks, the leakage current passes through the zero-sequence current transformer. When the leakage current reaches 1 ampere, the leakage monitoring instrument sends an alarm signal.
[0019] The AC power supply and the backup power supply are equipped with dual power switches, which can disconnect the AC power supply in the event of a fire, generate electricity through the engine, and supply the normal operation of fire-fighting electrical equipment such as emergency lighting and smoke exhaust fans.
[0020] In the description of the present invention, it should be understood that the terms "left", "right", "up", "down", "top", "bottom", "front", "back", "inside", "outside", "back", "middle", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.
[0021] However, what is described above is only a specific embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the scope of protection of the patent of the present invention should still fall within the scope covered by the claims of the present invention.
Claims
1. A leakage alarm system for preventing false alarms, comprising a mains power supply and a backup power supply, wherein the mains power supply is connected to the backup power supply to form a dual power supply circuit; a current transformer and a dual power supply load circuit are connected to the dual power supply circuit, characterized in that: The neutral line connecting the mains power supply and the backup power supply is connected through the contact of the contactor, and the coil of the contactor is connected between the live line and the neutral line of the backup power supply.
2. A leakage alarm system for preventing false alarms according to claim 1, characterized in that: The mains power supply and the backup power supply are both three-phase four-wire systems, consisting of three live wires and one grounded neutral wire.
3. A leakage alarm system for preventing false alarms according to claim 2, characterized in that: The mains power supply and the backup power supply are also provided with dual power switches.
4. A leakage alarm system for preventing false alarms according to any one of claims 1 to 3, characterized in that: The current transformer uses a zero-sequence current transformer.
5. A leakage alarm system for preventing false alarms according to claim 4, characterized in that: The zero-sequence current transformer is also connected to a leakage monitoring instrument.
6. A leakage alarm system for preventing false alarms according to claim 4, characterized in that: The backup power supply is an AC three-phase generator.