Balanced special SVG (static var generator) for line voltage single-phase power supply load

Abstract

The utility model relates to the field of circuit filtering, in particular to a load balancing special SVG (static var generator) for line voltage single-phase power supply, which comprises an A-phase power supply UA, a B-phase power supply UB and a C-phase power supply UC, a load Load is connected between the A-phase power supply UA and the C-phase power supply UC, the A-phase power supply UA is connected with the input end of an AB-SVG module, the C-phase power supply UC is connected with the input end of a BC-SVG module, and the A-phase power supply UA is connected with the input end of a BC-SVG module. The output end of the AB-SVG module is connected with the output end of the BC-SVG module, and the output end of the B-phase power supply UB is connected to a connecting line between the output end of the AB-SVG module and the output end of the BC-SVG module. The product adopts two three-level SVGs, and functions of zero current, active power output, active power input, reactive power output, reactive power input and the like can be realized by adjusting phase angles of voltage and current, so that the requirement of three-phase balance is met.

Description

Technical Field

[0001] The utility model relates to the field of circuit filtering, in particular to a SVG dedicated for balancing loads powered by line voltage single-phase power supply. Background Art

[0002] Generally, the power supply of factories is a three-phase power supply system, but some loads such as electroplating and glass manufacturing industries require single-phase power supply of high-power heating power. Due to the requirement of single-phase power supply, the current of the N line will be too large, so the line voltage power supply method is adopted. However, this power supply mode will lead to unbalanced power supply of the power grid. Severe imbalance of the power grid may cause overload of individual power supply phases, thus affecting the safe operation of the power supply and distribution system. For this load, the balancing dedicated SVG provided by our company successfully solves the three-phase balancing problem through reactive power compensation of the other two phases. Traditional three-phase balancing products are all realized by parallel capacitors, but due to the uncontrollable threshold capacity of the capacitor and the aging and damage of the capacitor, the reactive power of individual phases of the equipment often increases suddenly, or the cable suddenly heats up. The damaged capacitor does not have an alarm function unless it is manually detected. This makes a large number of equipment have safety risks. What's more, it is not until the single-phase cable is damaged due to heating that the balancing is discovered to be damaged. Utility Model Content

[0003] In view of the above technical problems in the related art, the utility model proposes a dedicated SVG for balancing loads powered by line voltage single-phase power supply, which can overcome the above shortcomings of the prior art.

[0004] In order to achieve the above technical purpose, the technical solution of the utility model is implemented as follows:

[0005] A SVG dedicated for balancing loads of line voltage single-phase power supply, comprising an A-phase power supply U A、 B phase power supply U B 、C phase power supply U C , the A phase power supply U A and C phase power supply U C A load Load is connected between the A phase power supply U A Connect the input terminal of the AB-SVG module to the C-phase power supply U C The input end of the BC-SVG module is connected to the output end of the AB-SVG module, and the output end of the AB-SVG module is connected to the output end of the BC-SVG module. B The module is also connected to a line between an output end of the AB-SVG module and an output end of the BC-SVG module.

[0006] Furthermore, the A-phase power supply U AReactors L1 and L2 are connected in series with the AB-SVG module.

[0007] Furthermore, the B-phase power supply U B Connected to the connection line between the reactor L1 and the reactor L2.

[0008] Furthermore, the B-phase power supply U B A capacitor C1 is provided between the connection point of the line between the reactor L1 and the reactor L2.

[0009] Furthermore, the C-phase power supply U C Reactors L4 and L5 are connected in series between the BC-SVG module.

[0010] Furthermore, the B-phase power supply U B Connected to the connection line between the reactor L4 and the reactor L5.

[0011] Furthermore, the B-phase power supply U B A capacitor C2 is provided between the connection point of the line between the reactor L4 and the reactor L5.

[0012] Furthermore, the B-phase power supply U B A B-phase feed inductor L3 is connected to it.

[0013] Furthermore, the AB-SVG module or the BC-SVG module is preferably connected in parallel with an electrolytic capacitor C3.

[0014] Furthermore, the AB-SVG module or the BC-SVG module is preferably a three-level SVG.

[0015] Further, the load Load is preferably a heating load.

[0016] Furthermore, the line voltage between phases A and B is U AB , the line voltage between phase B and phase C is U BC； The current of phase A is I A , the B phase current is I B , C phase current is I C , the current flowing through the load Load is I CA； When using, I C =I A =I CA , I B = 0, AB-SVG module output leads U AB 90 degree capacitive current I AB =0.577I CA ; The output of the three-level BC-SVG module lags behind U BC90 degree inductive current I BC =0.577ICA; after compensation, the transformer output current is balanced, I A =I B =I C =0.577I CA , not only the power supply is balanced, but also the power factor is close to 1.

[0017] Beneficial effects of the utility model: the product can be adjusted without threshold, always keep the balance degree above 5%, and has perfect alarm function and background transmission function, which greatly improves the reliability of equipment and the safety of power supply and distribution. The product adopts two three-level SVGs, which can achieve zero current, active output, active input, reactive output, reactive input and other functions by adjusting the phase angle of voltage and current, so as to achieve the requirements of three-phase balance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a circuit diagram of a three-dimensional perspective of a dedicated SVG for balancing loads powered by line voltage single-phase power supply according to the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the utility model.

[0020] like Figure 1 As shown, in order to facilitate understanding of the above technical solution of the present invention, the above technical solution of the present invention is described in detail below through specific usage methods.

[0021] In specific use, the dedicated SVG for balancing the load for line voltage single-phase power supply includes an A-phase power supply U A、 B phase power supply U B 、C phase power supply U C , the A phase power supply U A and C phase power supply U C A load Load is connected between the A phase power supply U A Connect the input terminal of the AB-SVG module to the C-phase power supply U C The input end of the BC-SVG module is connected to the output end of the AB-SVG module, and the output end of the AB-SVG module is connected to the output end of the BC-SVG module. B The module is also connected to a line between an output end of the AB-SVG module and an output end of the BC-SVG module.

[0022] In a specific embodiment, the A phase power supply U A Reactors L1 and L2 are connected in series with the AB-SVG module.

[0023] In a specific embodiment, the B phase power supply U B Connected to the connection line between the reactor L1 and the reactor L2.

[0024] In a specific embodiment, the B phase power supply U B A capacitor C1 is provided between the connection point of the line between the reactor L1 and the reactor L2.

[0025] In a specific embodiment, the C phase power supply U C Reactors L4 and L5 are connected in series between the BC-SVG module.

[0026] In a specific embodiment, the B phase power supply U B Connected to the connection line between the reactor L4 and the reactor L5.

[0027] In a specific embodiment, the B phase power supply U B A capacitor C2 is provided between the connection point of the line between the reactor L4 and the reactor L5.

[0028] In a specific embodiment, the B phase power supply U B A B-phase feed inductor L3 is connected to it.

[0029] In a specific embodiment, the AB-SVG module or the BC-SVG module is preferably connected in parallel with an electrolytic capacitor C3.

[0030] In a specific embodiment, the AB-SVG module or the BC-SVG module is preferably a three-level SVG.

[0031] In a specific embodiment, the load Load is preferably a heating load.

[0032] In a specific embodiment, the line voltage between phases A and B is U AB , the line voltage between phase B and phase C is U BC； The current of phase A is I A , the B phase current is I B , C phase current is I C , the current flowing through the load Load is I CA； When using, I C =I A =I CA , I B= 0, AB-SVG module output leads U AB 90 degree capacitive current I AB =0.577I CA ; The output of the three-level BC-SVG module lags behind U BC 90 degree inductive current I BC =0.577ICA; after compensation, the transformer output current is balanced, I A =I B =I C =0.577I CA , not only the power supply is balanced, but also the power factor is close to 1.

[0033] Specific working principle: Figure 1 As shown, the “load” is represented by U A and Uc power supply (the traditional system may also be powered by BC or AB, but its use principle is the same as above and will not be repeated here. B There is no load connected, so when the system is used, U B The current is zero because of the three-phase power supply. Therefore, the three-phase current must be balanced, so we use two three-level SVGs here. The two three-level SVGs can achieve zero current, active output, active input, reactive output, reactive input and other functions by adjusting the phase angle of voltage and current, thereby achieving the three-phase balance requirement.

[0034] U A It is a three-phase power supply, A phase, U B It is a three-phase B-phase power supply, U C It is a three-phase power supply with phase C. "Load" is a user's single-phase load. As can be seen from the figure above, the load is powered by phases A and C (or B, C or C, A). Figure 1 In the embodiment adopted by the utility model, the B-phase power supply phase is not connected to the load.

[0035] Therefore, the "load" is connected to the AC phase, and the output resistive current I CA . Transformer output current I C =I A =I CA , I B =0.

[0036] The three-level AB-SVG module output leads U AB (Line voltage between phases A and B) 90 degree capacitive current I AB =0.577I CA ; The output of the three-level BC-SVG module lags behind U BC (Line voltage between phases B and C) 90 degrees inductive current I BC =0.577ICA.

[0037] After compensation, the transformer output current is balanced, I A =I B =I C =0.577I CA , not only the power supply is balanced, but also the power factor is close to 1. Since the load current I CA is variable, requiring the module output current I AB and I BC Fast track compensation.

[0038] In summary, with the help of the above technical solutions, this product can be adjusted without threshold, always keep the balance degree above 5%, and has perfect alarm function and background transmission function, which greatly improves the reliability of equipment and the safety of power supply and distribution. This product uses two three-level SVGs, which can achieve zero current, active output, active input, reactive output, reactive input and other functions by adjusting the phase angle of voltage and current, so as to achieve the requirements of three-phase balance.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dedicated SVG for balancing loads powered by line voltage single-phase power, characterized in that: Including A phase power supply U A , B phase power supply U B 、C phase power supply U C , the A phase power supply U A and C phase power supply U C A load Load is connected between the A phase power supply U A Connect the input terminal of the AB-SVG module to the C-phase power supply U C The input end of the BC-SVG module is connected to the output end of the AB-SVG module, and the output end of the AB-SVG module is connected to the output end of the BC-SVG module. B The module is also connected to a line between an output end of the AB-SVG module and an output end of the BC-SVG module.

2. The SVG dedicated for balancing according to claim 1, characterized in that: The A phase power supply U A Reactors L1 and L2 are connected in series with the AB-SVG module.

3. The SVG dedicated for balancing as claimed in claim 2, characterized in that: The B phase power supply U B Connected to the connection line between the reactor L1 and the reactor L2.

4. The SVG dedicated for balancing as claimed in claim 3, characterized in that: The B phase power supply U B A capacitor C1 is provided between the connection point of the line between the reactor L1 and the reactor L2.

5. The SVG dedicated for balancing according to claim 1, characterized in that: The C phase power supply U C Reactors L4 and L5 are connected in series between the BC-SVG module.

6. The SVG dedicated for balancing as claimed in claim 5, characterized in that: The B phase power supply U B Connected to the connection line between the reactor L4 and the reactor L5.

7. The SVG dedicated for balancing according to claim 6, characterized in that: The B phase power supply U B A capacitor C2 is provided between the connection point of the line between the reactor L4 and the reactor L5.

8. The SVG dedicated for balancing according to claim 1, characterized in that: The B phase power supply U B A B-phase feed inductor L3 is connected to it.

9. The SVG dedicated for balancing according to claim 1, characterized in that: The AB-SVG module or the BC-SVG module is connected in parallel with an electrolytic capacitor C3.

10. The SVG dedicated for balancing according to claim 1, characterized in that: The AB-SVG module or the BC-SVG module is a three-level SVG.

Images