CN109687570B - Zero-flicker low-voltage power distribution system and operation method - Google Patents

Zero-flicker low-voltage power distribution system and operation method Download PDF

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Publication number
CN109687570B
CN109687570B CN201811542418.XA CN201811542418A CN109687570B CN 109687570 B CN109687570 B CN 109687570B CN 201811542418 A CN201811542418 A CN 201811542418A CN 109687570 B CN109687570 B CN 109687570B
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power supply
switch
power
emergency
load
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CN109687570A (en
Inventor
赖祥生
尚博
康琦
马文营
刘动
程序
张宏炯
钱叶牛
鲁籍元
丁丹蕾
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State Grid Corp of China SGCC
State Grid Beijing Electric Power Co Ltd
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State Grid Corp of China SGCC
State Grid Beijing Electric Power Co Ltd
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/062Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for AC powered loads
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/08Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems requiring starting of a prime-mover

Abstract

The invention discloses a zero-flicker low-voltage power distribution system and an operation method thereof, wherein the zero-flicker low-voltage power distribution system comprises a first power supply and a second power supply which are respectively connected with two common buses in a switching station; one end of the emergency bus is respectively connected with the mobile emergency power supply and the first power supply through a first dual-power automatic transfer switch; the other end of the emergency bus is connected with a static energy storage uninterrupted power supply at the user side; and a second dual power automatic transfer switch or solid state transfer switch connected to the user load. The invention avoids the switching operation of the load side dual-power automatic transfer switch power supply under the fault, thereby solving the problem of load flicker caused by voltage sag in the power supply switching and simultaneously solving the problem of voltage fluctuation. If the static energy storage uninterrupted power supply fails or is not supplemented by a power supply before the electric quantity is exhausted, the 2# dual-power automatic transfer switch is used for switching the power supply to a right path for supplying power, and sensitive load flicker caused by voltage sag can occur in power supply switching.

Description

Zero-flicker low-voltage power distribution system and operation method
[ technical field ] A method for producing a semiconductor device
The invention belongs to the technical field of power systems, and relates to an emergency power supply system, in particular to a zero-flicker low-voltage power distribution system and an operation method.
[ background of the invention ]
The low-voltage distribution system is closely related to the electricity utilization users, so whether the system can run healthily or not is directly related to the electricity utilization quality of the users.
At present, a common low-voltage power distribution system mostly adopts one-way or two-way power supply, a dual-power automatic transfer switch ATS and a static energy storage uninterruptible power supply UPS are configured to realize power supply switching and short-time continuous power supply under the condition of failure, a mobile power supply vehicle is also configured to serve as a temporary emergency power supply, and although the devices can temporarily recover power supply under certain failure conditions, the time required from power failure to power recovery is different from tens of seconds to several hours, so that the common power supply requirement is influenced. In important places, even very brief power outages can cause huge influence and loss. And various devices do not have a complete set of system wiring, and do not form efficient coordination for various degrees of faults.
The ordinary load adopts the emergency power supply configuration of 'dual power supply + dual power supply automatic transfer switch ATS', and the electric wiring of a certain ordinary load is shown in figure 1.
An automatic transfer switching (ats) switch is mainly used in an emergency power supply system, and is a switching device for automatically switching a load circuit from one power source to another standby power source, and the switching device is of a mechanical structure, and the switching time is over 100ms, which causes load power failure.
The dual power supplies of the common load are from different low-voltage buses, and are switched to the other path of power supply through the dual power supply automatic transfer switch ATS under the condition of single-path fault. The configuration of the dual-power supply and dual-power supply automatic transfer switch ATS solves the problem of power failure caused by single-path faults, but cannot solve the problem of power failure caused by double-path faults and resist voltage fluctuation, and load flicker caused by voltage sag occurs in power supply switching.
For important loads with relatively low power supply requirements, an emergency power supply configuration of 'dual power supplies + emergency buses + dual power automatic transfer switches ATS + mobile emergency power supplies' is adopted, and the electrical wiring is shown in fig. 2.
The emergency bus is usually connected with the common bus through a dual-power automatic transfer switch ATS, and the dual-power automatic transfer switch ATS connects the emergency bus with the common bus and breaks the emergency bus with an external power supply under normal conditions. When the common bus fails, the dual-power automatic transfer switch ATS breaks the emergency bus and the common bus and is communicated with an external power supply. The emergency bus has the function of distinguishing important loads from common loads, and only the important loads are selectively and continuously supplied with power through the mobile emergency power supply when the common bus section fails. All 23 power distribution rooms in the demonstration area are provided with emergency buses, and all important loads are connected to the emergency buses. The emergency bus extends to the outer wall of the building, the quick connection box is arranged, and the emergency power supply vehicle can be connected in 2 minutes.
When the bus fails, the emergency power supply vehicle continuously supplies power to the important load through the emergency bus. The emergency power supply configuration of the dual power supply, the emergency bus, the dual power supply automatic transfer switch ATS and the mobile emergency power supply solves the problem of power failure caused by dual-path faults, but voltage fluctuation cannot be resisted, and load flickering caused by voltage sag can occur in power supply switching.
In summary, a low voltage power distribution system with shorter fault isolation time and power switching time is required, including wiring forms and devices, to ensure that the most sensitive loads are not affected.
[ summary of the invention ]
The invention provides a zero-flicker low-voltage power distribution system and an operation method thereof, aiming at providing continuous power supply at the moment of line power failure and resisting voltage fluctuation.
In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:
a zero flicker low voltage power distribution system comprising:
the first power supply and the second power supply are respectively connected with two common buses in the switching station;
one end of the emergency bus is respectively connected with the mobile emergency power supply and the first power supply through a first dual-power automatic transfer switch ATS; the other end of the emergency bus is connected with a static energy storage Uninterrupted Power Supply (UPS) at the user side; and
and a user side load is respectively connected with the static energy storage uninterrupted power supply UPS and the second power supply through the second dual-power automatic transfer switch ATS.
The invention further improves the following steps:
the mobile emergency power supply adopts an emergency power supply vehicle, and the emergency power supply vehicle is connected with a first automatic dual-power-supply changeover switch ATS through a quick connection box.
The mobile emergency power supply adopts a mobile flywheel or a diesel generator.
A zero flicker low voltage power distribution system comprising:
the first power supply and the second power supply are respectively connected with two common buses in the switching station;
one end of the emergency bus is respectively connected with the mobile emergency power supply and the first power supply through a first dual-power automatic transfer switch ATS; the other end of the emergency bus is connected with a static energy storage Uninterrupted Power Supply (UPS) at the user side; and
and the user side load is respectively connected with the static energy storage uninterrupted power supply UPS and the second power supply through the solid state change-over switch SSTS.
The further improvement is that:
the mobile emergency power supply adopts an emergency power supply vehicle, and the emergency power supply vehicle is connected with a first automatic dual-power-supply changeover switch ATS through a quick connection box.
The mobile emergency power supply adopts a mobile flywheel or a diesel generator.
The solid state transfer switches SSTS are provided with a plurality of groups.
The solid-state change-over switch SSTS comprises a power switch Q1 and a power switch Q2 which are respectively connected with a main power supply and a standby power supply, wherein the main power supply and the standby power supply are respectively connected with a sensitive load through the power switch Q1 and the power switch Q2; a thyristor switch TS1 and a thyristor switch TS2 are connected in series between the power switch Q1 and the power switch Q2, a high-speed mechanical switch PS1 is connected in parallel to the thyristor switch TS1, and a high-speed mechanical switch PS2 is connected in parallel to the thyristor switch TS 2; the node between thyristor switch TS1 and thyristor switch TS2 is connected to the sensitive load through power switch Q0.
A method of operating a zero flicker low voltage power distribution system, comprising the steps of:
when the voltage of the main power supply is temporarily reduced and the temporarily reduced amplitude value exceeds the limit value which can be borne by normal operation of a sensitive load, the solid-state change-over switch SSTS control system sends out a switching instruction, the high-speed mechanical switch PS1 is switched off, the thyristor switch TS1 is triggered to be switched on, and current is immediately transferred to the thyristor;
then, the trigger signal of the thyristor switch TS1 is cancelled, and the thyristor switch TS1 is turned off when the current passes zero for the first time; then triggering the thyristor switch TS2 on the other side to be conducted, and starting the standby power supply to supply power to the load;
after the switch is stabilized, the control system sends a command of closing the high-speed mechanical switch PS2 again, at the moment, the thyristor switch TS2 is still conducted, the voltage drop at two ends is close to zero, no electric arc is generated when the high-speed mechanical switch PS2 is closed, and then the trigger signal of the thyristor switch TS2 is cancelled to complete the whole switching process.
The further improvement is that:
when the solid state switching switch SSTS requires maintenance, the load is powered uninterruptedly through either the power switch Q1 or the power switch Q2.
Compared with the prior art, the invention has the following beneficial effects:
according to the emergency power supply configuration of the dual power supply, the emergency bus, the static energy storage uninterrupted power supply UPS, the dual power supply automatic transfer switch ATS and the mobile emergency power supply, the switching operation of the dual power supply automatic transfer switch ATS on the load side under a fault is avoided, so that the problem of load flicker caused by voltage sag in power supply switching is solved, and the problem of voltage fluctuation is solved. However, the emergency power supply configuration cannot completely ensure "zero flicker" of power supply because the above process is based on the premise that the static energy storage uninterruptible power supply UPS can continuously and normally operate. If the UPS fails or is not supplemented by power before the electric quantity is exhausted, the 2# dual-power automatic transfer switch ATS switches the power to the right path for power supply, and sensitive load flicker caused by voltage sag occurs in the power switching.
The invention organically combines an emergency bus, a dual-power automatic transfer switch ATS, a static energy storage uninterruptible power supply UPS, a solid state transfer switch SSTS and an emergency power supply vehicle, and provides a set of low-voltage distribution system wiring mode with extremely high reliability. The emergency bus extends to the outer wall of the building, the power supply vehicle connection box is installed, the connection speed is high, and the connection is stable. By applying the mobile power supply vehicle and the dual-power automatic transfer switch ATS, power can be continuously supplied under the condition that all external power supplies are in failure. By applying the static energy storage uninterrupted power supply UPS and the solid-state change-over switch SSTS, the voltage fluctuation and the voltage sag can be resisted, and good electric energy quality can be continuously provided. The power supply switching time is within 5 milliseconds, even the most sensitive load is not affected, and zero flicker is realized. The static energy storage uninterruptible power supply UPS and the mobile power supply vehicle are equipped, and the emergency power supply capacity under extreme conditions such as disaster recovery, combat readiness and the like is achieved. The user can be according to actual demand, the equipment and the equipment of nimble selection configuration, and the practicality is strong.
[ description of the drawings ]
Fig. 1 is an electrical wiring diagram of an emergency power supply configuration in which a common load employs a "dual power supply + dual power supply automatic transfer switch ATS";
FIG. 2 is an electrical wiring diagram of an emergency power supply configuration employing "dual power supply + emergency bus + dual power automatic transfer switch ATS + mobile emergency power supply" for an important load with relatively low power requirements;
FIG. 3 is a diagram of the electrical wiring for the important loads of the present invention;
FIG. 4 is a diagram of the electrical wiring for a particularly important load of the present invention;
fig. 5 is a schematic diagram of a basic structure of the solid-state transfer switch SSTS of the present invention.
Wherein: 1-a first power supply; 2-a second power supply; 3-emergency power supply vehicle; 4-quick connection box; 5-an emergency bus; 6-first dual power automatic transfer switch ATS; 7-second dual-power automatic transfer switch ATS; 8-solid state transfer switch SSTS; 9-sensitive load.
[ detailed description ] embodiments
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Various structural schematics according to the disclosed embodiments of the invention are shown in the drawings. The figures are not drawn to scale, with certain details exaggerated and possibly omitted for the purpose of eliminating expression. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.
In the context of the present disclosure, when a layer/element is referred to as being "on" another layer/element, it can be directly on the other layer/element or intervening layers/elements may be present. In addition, if a layer/element is "on" another layer/element in one orientation, then that layer/element may be "under" the other layer/element when the orientation is reversed.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The invention is described in further detail below with reference to the accompanying drawings:
example 1:
as shown in fig. 3, in order to provide continuous power supply at the moment of line power loss and simultaneously resist voltage fluctuation, a static energy storage uninterruptible power supply UPS is connected in series between the emergency bus 5 and the load, and an emergency power supply configuration of "dual power supply + emergency bus 5+ static energy storage uninterruptible power supply UPS + dual power supply automatic transfer switch ATS + mobile emergency power supply" is formed for an important load with a relatively high power supply requirement;
the 4# bus and the 5# bus of the switch station are respectively connected with the 4# bus and the 5# bus of the power distribution room to form a double power supply consisting of a first power supply 1 and a second power supply 2; one end of an emergency bus 5 is respectively connected with a mobile emergency power supply and a first power supply 1 through a first dual-power automatic transfer switch ATS 6, the other end of the emergency bus 5 is connected with a static energy storage Uninterruptible Power Supply (UPS) power supply, and an important load on a user side is respectively connected with the static energy storage Uninterruptible Power Supply (UPS) power supply and a second power supply 2 through a second dual-power automatic transfer switch ATS 7, so that an emergency power supply configuration of 'dual power supply + emergency bus 5+ static energy storage Uninterruptible Power Supply (UPS) + dual-power automatic transfer switch ATS + mobile emergency power supply' is formed. The mobile emergency power supply adopts an emergency power supply vehicle 3, and the emergency power supply vehicle 3 is connected with a first automatic double-power-supply changeover switch ATS 6 through a quick connection box 4.
A static energy storage uninterruptible Power supply (ups), which is a system device that converts direct current into commercial Power through modules such as an inverter and is mainly used to provide stable and uninterrupted Power supply for a single computer, a computer network system or other Power electronic devices such as an electromagnetic valve and a pressure transmitter. When the mains supply input is normal, the static energy storage uninterrupted power supply UPS supplies the mains supply to a load for use after stabilizing the voltage, and the static energy storage uninterrupted power supply UPS is an alternating current type voltage stabilizer and also charges a built-in battery; when the commercial power is interrupted, the static energy storage uninterrupted power supply UPS immediately supplies the direct current electric energy of the battery to the load by a method of switching and converting the inverter to continuously supply 220V alternating current to the load, so that the load keeps normal work and protects the software and hardware of the load from being damaged. Static energy storage uninterruptible power supply UPS devices typically provide protection against over-voltage or under-voltage.
Example 2
As shown in fig. 4, for a particularly important load, an emergency power supply configuration of "dual power supply + emergency bus 5+ static energy storage uninterruptible power supply UPS + solid state transfer switch SSTS 8+ mobile emergency power supply" is adopted;
the 4# bus and the 5# bus of the switch station are respectively connected with the 4# bus and the 5# bus of the power distribution room to form a double power supply consisting of a first power supply 1 and a second power supply 2; one end of an emergency bus 5 is connected with a mobile emergency power supply and a first power supply 1 through a first dual-power automatic transfer switch ATS 6 respectively, the other end of the emergency bus 5 is connected with a static energy storage Uninterruptible Power Supply (UPS) power supply, and a user-side important load is connected with the static energy storage Uninterruptible Power Supply (UPS) power supply and a second power supply 2 through a solid state transfer switch SSTS 8 respectively, so that an emergency power supply configuration of 'dual power supplies + the emergency bus 5+ the static energy storage UPS + the solid state transfer switch SSTS 8+ the mobile emergency power supply' is formed. The mobile emergency power supply adopts an emergency power supply vehicle 3, and the emergency power supply vehicle 3 is connected with a first automatic double-power-supply changeover switch ATS 6 through a quick connection box 4.
A solid state Transfer Switch (SSTS 8) is an automatic switching device for an alternative power supply, and when the main power supply is in a normal voltage range, a load is always connected to the main power supply; when the main power supply fails, the load is automatically switched to the standby power supply, and after the main power supply is recovered to be normal, the load is automatically switched to the main power supply. The SSTS 8 is typically switched for 5ms, does not cause sensitive load power failure, and is widely applied to an automatic system in the power industry, a power supply system in the petrochemical industry, a computer and remote communication center, an automation and safety system of a building and the like.
As shown in fig. 5, fig. 5 is a basic structure of a solid state transfer switch SSTS 8, including a power switch Q1 and a power switch Q2 connected to a main power supply and a backup power supply, respectively, which are connected to a sensitive load 9 through the power switch Q1 and the power switch Q2, respectively; a thyristor switch TS1 and a thyristor switch TS2 are connected in series between the power switch Q1 and the power switch Q2, a high-speed mechanical switch PS1 is connected in parallel to the thyristor switch TS1, and a high-speed mechanical switch PS2 is connected in parallel to the thyristor switch TS 2; the node between thyristor switch TS1 and thyristor switch TS2 is connected to the sensitive load 9 through power switch Q0.
The working process of the solid-state change-over switch SSTS 8 is as follows:
during normal operation, the load is powered by the mains power supply, the parallel high speed mechanical switch PS1 is closed, the thyristor switch TS1 is bypassed, and the power switch Q0 is closed. When the voltage of a main power supply drops temporarily and the temporarily dropped amplitude exceeds the limit value which can be borne by normal operation of a sensitive load, the solid-state change-over switch SSTS 8 control system sends a switching instruction, the high-speed mechanical switch PS1 is turned off, the thyristor switch TS1 is triggered to be turned on at the same time, current is immediately transferred to the thyristor, when the high-speed mechanical switch PS1 is turned on, electric arcs hardly exist, and the high-speed mechanical switch PS1 can be rapidly extinguished even if the high-speed mechanical switch PS1 is turned on. The trigger signal to thyristor switch TS1 is then deactivated and the thyristor will thereafter turn off at the first zero crossing of the current. And then triggers the thyristor switch TS2 on the other side to turn on and the backup power supply begins to supply power to the load. At this point, the handover has actually been completed. After a period of time is stable, the control system sends a command of closing the high-speed mechanical switch PS2 again, at the moment, the thyristor switch TS2 is still conducted, the voltage drop at two ends is close to zero, no electric arc is generated when the high-speed mechanical switch PS2 is closed, and then the trigger signal of the thyristor switch TS2 is cancelled to complete the whole switching process. When the solid state switching switch SSTS 8 requires maintenance, the load is supplied uninterruptedly through the power switch Q1 or the power switch Q2.
As shown in fig. 4, when the static energy storage UPS is continuously powered for 30 minutes, the static energy storage UPS is not supplemented or fails, the solid state switch SSTS 8 switches the power supply to the right side within 5 milliseconds, even if the sensitive load 9 is not affected, and the power supply is "zero-flickering" in the whole process. The invention can meet the requirement of zero-flicker power supply, and all circuits and devices configured from a distribution transformer to the tail end of a load are collectively called a 'zero-flicker' power supply system. Fig. 4 shows a zero-flicker emergency power supply system which is formed by combining a dual power supply, an emergency bus 5, a static energy storage uninterruptible power supply UPS, a solid-state transfer switch SSTS 8 and a mobile emergency power supply.
The principle of the invention is as follows:
the quality of the electric energy refers to the quality of the alternating current electric energy supplied to the user terminals through the utility grid. An ideal utility grid should supply consumers with a constant frequency, sinusoidal waveform, and standard voltage. Meanwhile, in a three-phase alternating current system, the amplitudes of the phase voltages and the current of each phase are equal in magnitude and symmetrical in phase, and the phase difference is 120 degrees. However, because the devices such as the generator, the transformer and the line in the system are nonlinear or asymmetric, the load property is variable, and the regulation and control means are imperfect, and the reasons of operation, external interference and various faults do not exist, the ideal state does not exist, so that various problems in the links of power grid operation, power equipment and power supply and utilization are generated, and the concept of power quality is generated. Understanding from different perspectives, in the sense of power quality, generally includes:
(1) voltage quality: the concept of whether the electric energy supplied to the user by the power supply enterprise is qualified or not is reflected by the deviation of the actual voltage and the ideal voltage. This definition can include most power quality issues, but cannot include frequency-induced power quality issues, nor impact and pollution of the consumer on the power quality of the grid.
(2) Current quality: the current variation closely related to the voltage quality is reflected, and the power consumers not only have the requirements on constant frequency and sine waveform of the alternating current power supply, but also need the current waveform and the supply voltage to be in the same phase so as to ensure the operation of high power factors. This definition contributes to the improvement of the power quality of the grid and the reduction of line loss, but does not summarize most of the power quality problems due to voltage reasons.
(3) The power supply quality is as follows: the technical meaning refers to voltage quality and power supply reliability, and the non-technical meaning refers to service quality. The method comprises the reflecting speed of the power supply enterprise on the complaints of the users, the rationality and the transparency of the power price composition and the like.
(4) The electricity consumption quality is as follows: including the current quality and the right, responsibility and obligation of the consumers reflecting the interaction and influence of the supply and the consumption, and also including whether the consumers are on schedule, such as paying the electricity fee.
Currently, research and solution of the quality problem of electric energy has become a urgent task in power development. The main research subjects include:
(1) the influence of the harmonic waves on the power quality pollution of the power grid is researched and corresponding countermeasures are taken. Due to the development of metal smelting enterprises such as steel and iron, the increase of rectifying equipment in the chemical industry and the development and application of high-power thyristor rectifying devices and power electronic devices, the harmonic influence of a public power grid becomes more and more serious, the waveform of a power supply generates serious distortion, and the safe and reliable operation of the power grid is influenced.
(2) And (5) researching the influence of the harmonic waves on the electric power metering device and taking corresponding measures. Due to waveform distortion, accuracy and precision of electric power measurement are affected, measurement errors are caused, additional power loss is generated, and unnecessary economic loss is caused.
(3) The influence of the electric energy quality pollution on high and new technology enterprises is researched and corresponding technical means are adopted. Because computer systems, automated production pipelines controlled based on microelectronic technology, emerging IT industries, microelectronic chip manufacturing enterprises and the like have higher requirements and sensitivity degrees on electric energy quality than general electric power equipment, any transient and transient electric energy quality problem can cause damage or abnormal operation of the equipment, influence normal production and cause economic loss for power users.
(4) Development of an electric energy quality control device. The basic function of the power quality control device is to improve the power quality even under any condition, even extremely bad power supply condition, ensure the stability and reliability of the power supply voltage and current, and immediately inhibit or eliminate the harmonic interference at the moment of generating the harmonic interference.
The 'zero flicker' means that the fluctuation of the power supply voltage at the tail end is lower than 1 percent of the rated voltage, so that a person cannot perceive the visual sensation caused by unstable light illumination. The zero-flicker low-voltage power distribution system is a general name of a whole set of devices from a distribution transformer to the tail end of a load, which can meet the zero-flicker power supply requirement when the quality of electric energy changes.
When the 4# bus is power-off, the important load is continuously supplied with power by the static energy storage uninterrupted power supply UPS, the power supply time can reach 30 minutes, and the important load is not influenced. And the static energy storage uninterrupted power supply UPS has the functions of filtering and stabilizing voltage, can resist voltage fluctuation and temporary drop and improves the quality of electric energy.
In the invention, all 23 power distribution rooms in a demonstration area are provided with emergency buses 5, important loads are connected into the emergency buses 5, the emergency buses 5 extend to the outer wall of a building, and a quick connection box 4 is arranged. The user side optimally configures a dual-power automatic transfer switch ATS, a centralized static energy storage uninterruptible power supply UPS and distributed static energy storage uninterruptible power supplies UPS and EPS, and configures 5 groups of solid state transfer switches SSTS 8 for particularly important loads. An emergency guarantee center is arranged at a distance of 1.1 kilometers from a user, mobile emergency power supplies such as a mobile flywheel and a diesel generator are synchronously equipped, and a domestic first set of zero-flicker low-voltage power distribution system formed by a double power supply, an emergency bus 5, a static energy storage uninterruptible power supply UPS, a solid-state change-over switch SSTS 8 and the mobile emergency power supply is constructed.
The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.

Claims (2)

1. A method of operating a zero flicker low voltage power distribution system, the method of operation being based on a zero flicker low voltage power distribution system, comprising:
the first power supply (1) and the second power supply (2) are respectively connected with two common buses in the switching station;
one end of the emergency bus (5) is respectively connected with the mobile emergency power supply and the first power supply (1) through a first dual-power automatic transfer switch ATS (6); the other end of the emergency bus (5) is connected with a static energy storage Uninterrupted Power Supply (UPS) at the user side; the mobile emergency power supply adopts an emergency power supply vehicle (3), and the emergency power supply vehicle (3) is connected with a first automatic double-power-supply changeover switch ATS (6) through a quick connection box (4); the mobile emergency power supply adopts a mobile flywheel or a diesel generator;
the user side load is respectively connected with the static energy storage uninterrupted power supply UPS and the second power supply (2) through the solid state change-over switch SSTS (8); the solid state transfer switches SSTS (8) are provided with a plurality of groups; the solid-state change-over switch SSTS (8) comprises a power switch Q1 and a power switch Q2 which are respectively connected with a main power supply and a standby power supply, and the main power supply and the standby power supply are respectively connected with a sensitive load (9) through the power switch Q1 and the power switch Q2; a thyristor switch TS1 and a thyristor switch TS2 are connected in series between the power switch Q1 and the power switch Q2, a high-speed mechanical switch PS1 is connected in parallel to the thyristor switch TS1, and a high-speed mechanical switch PS2 is connected in parallel to the thyristor switch TS 2; the node between the thyristor switch TS1 and the thyristor switch TS2 is connected with a sensitive load (9) through a power switch Q0;
characterized in that the operating method comprises the following steps:
when the voltage of a main power supply is temporarily reduced and the temporarily reduced amplitude exceeds the limit value which can be born by normal operation of a sensitive load, the solid-state change-over switch SSTS (8) control system sends out a switching instruction, the high-speed mechanical switch PS1 is switched off, the thyristor switch TS1 is triggered to be switched on, and current is immediately transferred to the thyristor;
then, the trigger signal of the thyristor switch TS1 is cancelled, and the thyristor switch TS1 is turned off when the current passes zero for the first time; then triggering the thyristor switch TS2 on the other side to be conducted, and starting the standby power supply to supply power to the load;
after the switch is stabilized, the control system sends a command of closing the high-speed mechanical switch PS2 again, at the moment, the thyristor switch TS2 is still conducted, the voltage drop at two ends is close to zero, no electric arc is generated when the high-speed mechanical switch PS2 is closed, and then the trigger signal of the thyristor switch TS2 is cancelled to complete the whole switching process.
2. Method of operation of a zero flicker low voltage power distribution system according to claim 1, characterized in that the load is supplied uninterruptedly by means of the power switch Q1 or the power switch Q2 when the solid state change over switch SSTS (8) needs maintenance.
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