JP3189398B2 - Lighting shared power generator with unbalance compensation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for increasing the allowable value of an unbalanced load of a single-phase three-wire output-connected AC synchronous generator used for obtaining a three-phase four-wire output shared by lights. The present invention relates to a lighting combined power generation device with balance compensation.

[0002]

2. Description of the Related Art The distribution system and distribution voltage of low-voltage distribution lines include:
Single-phase two-wire 100V, single-phase two-wire 200V, single-phase three-wire 100 / 200V, single-phase three-wire 200V, three-phase four-wire 1
00 / 200V, etc., and among them, a three-phase four-wire system for distributing power to a lighting shared load is the most common. In this three-phase four-wire low-voltage distribution line shared by lighting, the pole transformer is configured with different capacity △ connection or different capacity V connection.

FIG. 7 shows a three-phase four-phase transformer composed of V-connection transformers of different capacity.
It shows a state of a group of consumers connected to a wire-type low-voltage distribution line. In the case of FIG. 7, compared with the single-phase transformer between the R-S phases, the single-phase capacity between the S-T phases is made larger (different capacity), and the neutral line is drawn out from the middle of the winding to obtain the single-phase 3 It constitutes a line circuit.

A load connected to this three-phase four-wire low-voltage distribution line is a single-phase 100 V or 200 V load (light load group) concentrated in a single-phase three-wire circuit between S-N-T phases. A three-phase 200V load (power load group) is mixed in the three-phase circuit between the -T phases. Such a low-voltage distribution system generally employs a tree-type system. Looking at the secondary side of a pole transformer in one bank as shown in FIG. 7, a three-phase unbalanced load (single-phase load + three-phase load group) is used. is there.

Here, for example, if the pole transformer is to be replaced in the distribution line shown in FIG. 7, it is necessary to temporarily disconnect the low voltage distribution line from the service power source (high voltage distribution line) when the low voltage distribution line is repaired. Occurs. In this case, during the construction of the distribution line, in order to prevent the power outage of the corresponding low-voltage customers during construction, as one means, use a mobile power generation device consisting of a three-phase AC synchronous generator driven by a motor or a power vehicle mounted on a vehicle, etc. There is a case where the secondary side of the pole transformer is opened to supply power to a corresponding group of low-voltage consumers temporarily from a power supply vehicle or the like.

[0006]

As a conventional example of the above-mentioned mobile power generator or power supply vehicle, a single-phase three-phase generator as shown in FIG.
There is a combination of a 出力 connection AC synchronous generator with line output and a three-phase balancing device. In FIG. 8, GE is a 発 電 connection generator, and U, V, and W phases of the generator GE are connected to a three-phase three-wire load group UNL serving as an unbalanced load shared by lights.
The U, V, and N phases are connected to a single-phase three-wire load group LO. P
BA is a three-phase equilibrium device, and this device PBA has U, V, W
The load currents detected by the load current detection current transformers CT-U, CT-V, and CT-W provided on the lines of each phase are supplied. This load current is detected by the detectors DT ₁ , DT ₂ , DT ₃ and the inverter I provided in the three-phase balancer PBA
NV. The inverter INV sends a compensation current to the generator according to the load current.

The three-phase balancer PB constructed as described above
A detects the load current of each phase of U, V, and W, and supplies the negative phase current as a compensation current to the generator side (power supply side) to remove the negative phase current from the power supply side current. In this case, an unbalanced load allowable limit is increased mainly by supplying a current for the positive phase.

However, in the conventional load current detecting method of the three-phase balancer PBA, when an N-phase current flows, a current for the same phase flows in each phase of the internal winding of the △ connection generator. As a result, the armature reaction magnetic field due to the generator phase current becomes unbalanced,
The magnetic imbalance has a disadvantage in that the internal impedance of the generator is unbalanced, and as a result, the voltage of each phase of the generator is unbalanced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a light source with imbalance compensation for balancing each phase current and each line voltage so that no magnetic unbalance occurs in the generator. An object is to provide a power generator.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention detects a △ connection generator for supplying power to a single-phase three-wire load group and a three-phase three-wire load group, and detects a load current. A three-phase balancing device for supplying a compensation current to the generator; and a load current detecting transformer for each of the U-phase, N-phase and V-phase lines for supplying power from the △ connection generator to the single-phase three-wire load group. A current transformer is provided, a first current transformer and a second current transformer are provided for the N-phase, and the N-phase first current transformer and the U-phase current transformer are connected in parallel, and the N-phase second current transformer is provided. And a V-phase current transformer connected in parallel, and the load current detected by the current transformers connected in parallel is supplied to the three-phase balancer.

[0011]

When a three-phase three-wire load group is unbalanced and an N-phase current flows, the N-phase detection current transformer detects this and supplies it to the three-phase balancing device. Then, the three-phase balancer operates so as to compensate for the negative phase current. Also, when the N-phase current does not flow, it operates in the same manner as a normal three-phase current detecting means using two current transformers.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG.
, The U-phase line _Lu and the V-phase line _Lv are provided with load current detection current transformers CT-U and CT-V, respectively. N
Phase line L _n 2 pieces of current transformers CT-N1, CT-N2 is provided in the current transformer CT-N1 and CT-U and CT-N
2 and CT-V are connected in parallel, respectively, and load current signal detectors DT _{1 to} DT ₃ provided in the three-phase balancer PBA.
Connected to. In particular, the current transformer CT-U and CT-N1 is connected to the detector DT ₁ and DT _3, the current transformer CT-V CT-
N2 is connected to the detector DT ₂ and DT _3.

Next, the operation of the above embodiment will be described. Even if the single-phase three-wire load group LO is unbalanced and an N-phase current flows, the armature reaction magnetic field due to each phase current of the generator GE is three-phase balanced to minimize the unbalance of the generator internal impedance. The means for performing this will be described below. The load current detecting current transformers CT-U and CT-V detect U-phase and V-phase currents from the U and V phases on the single-phase three-wire 200V output side in the embodiment of FIG. The N-phase current is detected from the N-phase (neutral phase) of the single-phase three-wire output by the current transformers CT-N1 and CT-N2. However, the current transformers CT-N1 and CT-N2 are twice as large as the current transformers CT-U and CT-V. (That is, for the same line current, the N-phase detection current is set to be の of the U- or V-phase detection current. For example, the current-transformation ratio of CT-U and CT-V is reduced to 1: 1. If [A], the current transformation ratio of CT-N1 and CT-N2 is 1: 0.5
[A] is obtained. ) Current transformers CT-U, CT-V, CT-N
1, CT-N2 has the following effects by connecting as shown in FIG.

(A) When the N-phase current does not flow (when the single-phase three-wire load group is balanced on the basis of the neutral phase and the 100 V-side load is equally distributed), the N-phase current becomes zero. Therefore, the load-side U, V, and W phase current components can be detected by the load current signal detector in the three-phase balancer using exactly the same principle as three-phase current detection by ordinary 2CT.

(B) When an N-phase current is flowing (when the distribution of loads on the 100 V side of the single-phase three-wire load group is uneven)
According to the following principle shown in FIG. 2, the load current detecting current transformer in the three-phase balancing device is not affected by the N-phase current component. In FIG. 2, for explanation of the principle, assuming that there is a load in which a unit current 1A flows only on one side of the 100 V circuit side of the single-phase three-wire output, as shown in FIG.
Equivalently, the current circulating in the U-V phase and the N-phase current are U-
The currents circulating on both sides of the 100 V circuit of the V and V-N phases are combined.

The important points here are as follows.
(A) The connection of the load current detecting current transformer shown in FIG. 1 detects that the load current is equivalent to the one shown in FIG. 2B when the N-phase current is flowing. (B) Since FIG. 2A including the zero-phase component is equivalently made from FIG. 2A including the zero-phase component using the load current detecting current transformer of the three-phase balanced device,
The three phase balancer operates to compensate for the negative phase current component in FIG. 2B. (C) Therefore, the current supplied from the 線 connection generator is obtained by adding the N-phase current of FIG.
A current in which the currents distributed to N and VN are superimposed flows.
(D) Here, one winding (between U and V) in the generator armature △ connection of the N-phase current of FIG. (180 ° phase difference), if the coupling coefficient of the same winding is assumed to be 1.0, the magnetic imbalance cancels out each other. Becomes difficult to be.

Next, a comparison will be made between the conventional example and the apparatus of the present invention. In order to make the comparison simple and easy to understand, the load is a single-phase 100 V (UN-N phase side) unit current (1.0 A) load for both the conventional example and the apparatus of the present invention, and the current ratio of the current transformer for load current detection. Is 1: 1 [A] for CT-U, CT-V, and CT-W,
CT-N1 and CT-N2 are set to 1: 0.5 [A].

FIG. 3 shows 1A between the U phase and the N phase of the device of the present invention.
FIG. 5 is a circuit diagram when a (amp) load is connected, and FIG. 4 shows each phase current on the power supply side, and FIG. 5 shows a positive phase current in a combined development of each phase current on the power supply side. As a result, the N-phase current shunt is as shown in FIG.

FIG. 9 is a circuit diagram when a 1 A load is connected between the U-phase and the N-phase in the conventional example.
As shown in FIG. 11, the positive-phase current component becomes as shown in FIG. 11 and the N-phase current component component becomes as shown in FIG.

The following table shows the secondary current CT, the load current signal detector current DT, the symmetrical DTS of the detected current and the compensation current CM of the load current detecting current transformer in the conventional example and the present invention.
P is shown by comparison.

[0021]

[Table 1]

From the above comparison, it is found that in the device of the present invention, no in-phase current is superimposed on the generator winding (VW) phase and (WU) phase, so that the magnetic unbalance of the generator is Can be eliminated, whereas in the conventional example, the common-mode current is superimposed on the above-mentioned phase, so that magnetic imbalance of the generator occurs.

In the above-described embodiment, the conventional one can be used for the (1) connection AC generator and the three-phase balancer, and the power can be supplied to the load circuit having the following five types of wiring systems.

(A) Lighting shared three-phase four-wire 200 / 100V circuit (B) Three-phase three-wire 200V circuit (C) Single-phase three-wire 200 / 100V circuit (D) Single-phase two-wire 200V circuit (E) Single Phase 2 line 100V circuit In the case of the above-described five power distribution system, if a mobile power supply vehicle is used, the power supply range is expanded to a range that cannot be tolerated by the generator alone. Further, the embodiments of the present invention can be used even if the voltages are different.

[0025]

As described above, according to the present invention,
By slightly changing the configuration of the load current detecting current transformer to the conventional one, it is possible to improve the characteristics (three-phase voltage balancing) at the time of a single-phase three-wire 100 V load unbalanced load. Further, even when an unbalanced load is applied, if the magnetic unbalance of the generator used as the power supply is suppressed, there is an advantage that the voltage waveform distortion is reduced accordingly.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing one embodiment of the present invention.

FIGS. 2A, 2B and 2C are explanatory diagrams for describing the operation of the embodiment.

FIG. 3 is an explanatory diagram of a specific conventional example for comparison with the conventional example.

4 is an explanatory diagram of each phase current on the power supply side in FIG. 3;

FIG. 5 is an explanatory diagram of a positive-sequence current in FIG. 3;

FIG. 6 is an explanatory diagram of an N-phase current in FIG. 3;

FIG. 7 is a circuit diagram of a three-phase four-wire low-voltage distribution line shared by lights.

FIG. 8 is a configuration explanatory view showing a conventional example.

FIG. 9 is an explanatory diagram of a conventional example for comparison with the embodiment of the present invention.

FIG. 10 is an explanatory diagram of each phase current on the power supply side in FIG. 9;

FIG. 11 is an explanatory diagram of a positive-sequence current in FIG. 9;

FIG. 12 is an explanatory diagram of an N-phase current shunt in FIG. 9;

[Explanation of symbols]

GE: Connection generator LO: Single-phase three-wire load group UNL: Three-phase three-wire load group PBA: Three-phase balancer CT-U, CT-V, CT-N1, CT-N2: Current for load current detection vessel

Claims (1)

(57) [Claims] A power generator for supplying power to a single-phase three-wire load group and a three-phase three-wire load group; and a three-phase balancer for detecting a load current and supplying a compensation current to the generator. Load current detecting current transformers are provided in the U-phase, N-phase and V-phase of the line for supplying power from the 単 connection generator to the single-phase three-wire load group, and the first and second transformers are provided in the N-phase. Install a sink,
An N-phase first current transformer and a U-phase current transformer connected in parallel, and an N-phase second current transformer and a V-phase current transformer connected in parallel;
A light / sharing generator with unbalance compensation, wherein a load current detected by a current transformer connected in parallel to both is supplied to the three-phase balancer.