JPH0495882A - Test load facility - Google Patents

Abstract

PURPOSE:To contrive energy saving with high efficiency while making possible the verification of a high-quality test by performing a load test as the electric power used for a load with the use of a semiconductor type converter and a semiconductor type inverter is returned to a power source. CONSTITUTION:Alternating electric power led from a device 3 to be tested is converted into direct electric power with the use of a converter 12 once. And at this time a load factor can be freely set on the converter 12 with the use of the principle of an active filter. The direct electric power is synchronized with the frequency of a power source bus 2 by the use of an inverter 13 to match with voltage so as to transmit into a power source side. The direct current voltage of the converter 12 and the inverter 13 is set to generate small voltage difference from the electric power during the time to control freely so as to make test data by plurally setting the load factor. A power factor can be also set and an arbitrary power factor test can be performed. As the result the load electric power of the device 3 to be tested is almost returned to an alternating current power source 1 and efficiency is improved because the electric power loss is conversion loss alone.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to test load equipment for testing various characteristics of electrical equipment such as motors, generators, transformers, and power converters.

B0 Summary of the Invention The present invention provides a test load facility for testing various characteristics of various electrical devices, which includes a converter that adjusts the load power factor as the load facility, and a converter that converts the output power of the converter into AC power at an arbitrary load factor. By installing an inverter that converts the power and returns it to the AC power bus, it is possible to reduce power loss and conduct high-quality load tests with high efficiency.

C1 Prior Art Conventionally, actual load tests on electrical equipment have been carried out using water resistors, reactors, etc. to take the load, and have been conducted in the following manner depending on each equipment.

■ Electric motor (motor) When there is only one motor, there are two methods: directly connecting a DC generator or grammar generator and consuming the load with a water resistor, etc.
There is a method of testing the current separately and calculating the test results equimetrically. When two motors with the same rating are connected directly,
There is a return method in which one unit is used as a motor and the other unit is used as a generator, and the loss is replenished from the power supply.

■ Generator When using only one generator, water is consumed by a water resistor. When there are two generators with the same rating, there is a return method in which they are connected directly as in (2) above.

■ There is a method of testing the transformer voltage and current separately and calculating it. (Same as motor) ■ Actual load test for power converters up to several hundred XVA class, over several hundred and several thousand K
In the VA class, tests are conducted separately for voltage (no-load test) and current (low-voltage current test), and results are determined by equivalent calculations.

D9 Problems to be solved by the invention As mentioned above, when there are two or more devices with the same rating, the return method is used, and when the capacity is very large, voltage and current tests are performed, and tests with less waste are performed. There is. However, in those that perform actual load tests, power is actually consumed by water resistors and the like, so the power used during the test is extremely wasted. For example, if we consider performing a temperature rise test on a 500KvA power converter, the load power factor is 0.85,
Assuming that it takes about 5 hours for the temperature to reach a constant value in the temperature rise test, and the electricity rate is 15 yen/KWh, 500XV
AX0. 85 (power factor) x 5 hours - 2125.

2125,, bX15 yen - 31875 yen.

Therefore, if an actual load test of 3,000 KvA were to be conducted every month, approximately 2.3 million yen worth of electricity would be wasted annually.

The present invention has been made in view of the above points, and its purpose is to:
The object of the present invention is to provide test load equipment that can achieve high efficiency and energy savings, as well as verify high-quality tests.

20 Means for Solving the Problems The present invention provides a converter that converts AC power led from a device under test into DC power and adjusts the load power factor in test load equipment for testing various characteristics of electrical equipment. , and an inverter that converts the output power of the converter into AC power at an arbitrary load factor and returns it to the AC power bus side.

AC power led from the machine under test is once converted into DC power by a converter. 'At this time, the load power factor can be set arbitrarily using the active filter principle. The output power of the converter is converted into AC power by an inverter and returned to the AC power source. At this time, if the DC voltage settings of the converter and inverter are different, the load factor can be set to 0, 25, 50, 75, or 100%, for example. In this way, most of the load power of the loaded test machine is returned to the power supply side, and the only power loss is the conversion loss (approximately 10%) in the converter and inverter, making testing much more efficient than conventional equipment. load equipment can be provided.

G. Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the overall system configuration, in which power is transferred between the device under test 3 connected to the bus bar 2 of the AC power supply 1 and the load equipment 4 as shown by the arrows.

The load equipment 4 is configured as shown in FIG. 2, for example.

In FIG. 2, AC power led from the device under test 3 is led via a breaker 10 and a transformer 11 to a converter 12 that converts the AC power into DC power. This converter 12 is a voltage type self-limiting PWM converter, and is composed of self-extinguishing semiconductor elements (power transistor, gate turn-off thyristor, etc.). converter 12
The output side of is an inverter 1 that converts DC power to AC power.
Connected to 3. This inverter 13 is a t-square self-limiting PWM inverter, and is composed of self-extinguishing semiconductor elements (power transistors, gate turn-off thyristors, etc.). The output side of the inverter 13 is connected to the bus bar 2 via an inverter transformer 14 and a breaker 15.

In the apparatus configured as described above, AC power led from the device under test 3 is once converted into DC power by the converter 12. At this time, the converter 12 can freely set the load power factor using the principle of an active filter. The DC power output from the converter 12 is synchronized with the frequency of the power supply bus 2 by an inverter 13, and the voltage is adjusted and sent to the power supply side. This power to be sent out can be freely controlled by setting the DC voltages of the converter 12 and inverter 13 and further creating a slight voltage difference between them. For this reason, the load factor was set to 0.25, 50.
It is also optional to create test data with settings such as 75.100%. Similarly, since the power factor can be set as described above, any load power factor test is also possible. When the test is conducted in this manner, most of the load power of the device under test 3 is returned to the AC power supply 1 side, and the only power loss is the conversion loss (about 10%) in the converter 12 and inverter 13.

Therefore, it is possible to provide a testing load facility that is much more efficient than the conventional one. Incidentally, the load equipment 4 can be connected to the converter 1 by removing the transformer 11 as shown in FIG.
2 may be configured with a diode or thyristor rectifier.

H0 Effects of the Invention As described above, according to the present invention, the semiconductor converter and inverter allow the load test to be performed while returning the power used as a load to the power source, resulting in the following excellent effects. It will be done.

(1) Unlike water resistors, which do not simply consume power, the power used for testing is returned to the power source, providing extremely highly efficient and energy-saving equipment.

(2) The load factor and load power factor of the loaded testing machine can be set at will, and settings can be easily changed and adjusted with a single setting device, so test setup can be done in a short time and speed up. be able to. On the other hand, with a water resistor, it takes time to raise and lower the electrode, and the setting cannot be done with high accuracy.

(3) Since the settings are electronic, accuracy and stability are high, and high-quality test results can be obtained. On the other hand, with water resistors, the resistance value constantly changes depending on the salt concentration in the water, liquid temperature, etc., making it difficult to maintain a stable load with high accuracy.

(4) Conventionally, a water resistor alone could provide only resistance, and in order to create a lagging power factor load, a separate hydraulic accelerator and its variable equipment (induction regulator, etc.) were required.
The setup was complicated and adjustments were difficult. In this respect, according to the present invention, the lagging power factor and the leading power factor can be set freely, and load equipment such as a reactor is not required.

(5) Since the present invention is an inverter type, it is stationary and has low noise.
Due to its high efficiency, it can be replaced as a new type of load equipment instead of returning generators, etc.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of load equipment according to the embodiment, and FIG. 3 is a circuit diagram showing another example of load equipment according to the embodiment. 1... AC power supply, 2... Power supply bus, 3... Machine under test, 4... Load equipment, 10.15... Breaker, 1
2...Converter, 13...Inverter, 14...
・Inverter transformer.

Claims (1)

[Claims] (1) In test load equipment for testing the various characteristics of electrical equipment, there is a converter that converts AC power derived from the equipment under test into DC power and adjusts the load power factor, and a converter that converts the output power of the converter to any load. Test load equipment characterized by comprising an inverter that converts the AC power into AC power at a constant rate and returns it to the AC power bus side.