KR101136910B1 - System and method for assessment of harmonic emission limits at cus transmission - Google Patents

Abstract

The present invention relates to a transmission system harmonic emission limit evaluation system and method. According to the present invention, the capacity comparison unit for comparing the harmonic load capacity of the customer and the short-circuit capacity of the system, the customer harmonic outflow threshold measurement to measure the harmonic outflow threshold when the customer's harmonic load capacity exceeds 0.1% of the system's short-circuit capacity Transmission system harmonic emission limit including the consumer harmonic prediction and the harmonic emission threshold comparison unit requesting the customer to take harmonic reduction measures when the consumer harmonic outflow estimate exceeds the consumer harmonic outflow limit by comparing the negative and consumer harmonic outflow estimates with the consumer harmonic outflow limits. Evaluation systems and methods can be provided.

Description

SYSTEM AND METHOD FOR ASSESSMENT OF HARMONIC EMISSION LIMITS AT CUS TRANSMISSION}

The present invention relates to a transmission system harmonic emission limit evaluation system and method.

Current harmonics management standards restrict voltage harmonics only to voltage THD (Total Harmonic Distortion), and in the case of current harmonics, only the image harmonics affecting the communication line are not considered. However, in Europe and the United States, the International Electrotechnical Commission (IEC) standards are used to assess harmonic emission limits.

The basic concept of the IEC standard is that harmonics entering the power system should not adversely affect most devices, and most devices must have sufficient immunity to harmonics. Strictly limiting harmonic emissions in IEC standards adds additional costs for harmonic suppression, while strictly limiting immunity criteria incurs additional costs in the manufacturing of equipment. Therefore, the harmonic generation standard of the power system and the immunity standard of the device are determined so that most devices are not damaged. To meet this, the compatibility level is used.

The compatibility level does not affect most devices because it only allows a small probability of the power system affecting the device. Based on this compatibility level, the utility company may exceed the criteria set in the operation phase, so plan and operate a planning level equal to or lower than the compatibility level in consideration of the margin.

The planning level is a value adopted by the utility that operates and plans the electricity system and is used to calculate the harmonic emission limit of the installation or load connected to the system in the area. The planned level cannot be higher than the compatibility level. In general, it is lower than the compatibility level because the margin must be sufficiently considered by factors such as the structural and electrical characteristics of the power system, the fundamental level of disturbance, the probability of resonance, and the disturbance phenomenon including the load curve.

Although the IEC standard calculates harmonic emission limits in consideration of the transmission system, it is difficult to evaluate the harmonic emission limit using the IEC standard because the conditions of the domestic transmission system and the overseas transmission system are different.

The present invention provides a harmonic emission limit evaluation system and method capable of effectively managing harmonics generated in a transmission system.

The present invention provides a system and method for evaluating harmonic emission limits of a consumer and a harmonic emission limit evaluation system that can be managed by the user.

According to an aspect of the invention, the capacity comparison unit for comparing the harmonic load capacity of the customer and the short circuit capacity of the system; A customer harmonic outflow limit measurement unit for measuring a harmonic outflow limit when the harmonic load capacity of the consumer exceeds 0.1% of the short-circuit capacity of the system; And a transmission system harmonic comparison unit including a consumer harmonic prediction value and a harmonic leakage threshold comparison unit for requesting a countermeasure for harmonic reduction when the consumer harmonic emission prediction value exceeds the consumer harmonic emission limit value by comparing a consumer harmonic emission prediction value with the consumer harmonic emission limit value. Emission limit assessment systems can be provided.

The capacity comparison unit may calculate the load capacity by receiving a voltage and a current of a customer connected to a transmission line.

The capacity comparator may notify the voltage or current information exceeding the reference value by comparing the voltage and current of the customer connected to the power transmission line with a set reference value.

로 계산할 수 있다.The harmonic outflow limit measurement unit is a harmonic outflow limit value for a non-linear facility for h (h is natural water) order harmonics.

Can be calculated as

Where E _Uhi Is the harmonic _emission limit of the nonlinear facility i for the h harmonics, G _hHV is the global level of the h harmonics in the high or ultra high voltage system, α is the harmonic synthesis index, S _t is the common coupling point (common coupling point Where the power can be supplied from the power system, the total available power of the system, S _i, is the rated capacity of the customer.

The harmonic synthesis index uses harmonic synthesis index for 5th or higher harmonics when the phase of the hth harmonic is within 90 °, but the harmonic synthesis index is between 1, 5 and 10 when the harmonic order is 5 or less, 1.4, If 10 or more, 2 can be applied.

The harmonic leakage limit measurement unit may be a value obtained by dividing a harmonic leakage threshold by the harmonic impedance of the nonlinear facility for the h-th harmonic in order to limit the leakage of the nonlinear load on the consumer side.

In the capacity comparison unit, the harmonic load capacity of the customer is 0.1% or less of the short-circuit capacity of the system, or the customer harmonic outflow prediction value and the harmonic outflow limit value comparison unit compare the customer harmonic outflow prediction value and the customer harmonic outflow limit value. If the consumer harmonics outflow prediction value is less than the consumer harmonics outflow threshold value can be supplied to the normal load.

According to another aspect of the invention, (a) comparing the harmonic load capacity of the customer and the short circuit capacity of the system; (b) measuring a harmonic outflow threshold when said customer's harmonic load capacity exceeds 0.1% of said system's short-circuit capacity; And (c) comparing the consumer harmonics outflow threshold with the consumer harmonics outflow forecast and requesting a customer to reduce harmonics when the consumer harmonics outflow forecast exceeds the consumer harmonics outflow threshold.

The step (a) may further include the step of calculating the harmonic load capacity by receiving the voltage and current of the customer connected to the transmission line.

The method may further include informing voltage or current information exceeding the reference value by receiving the input voltage and current of the customer connected to the transmission line and comparing the set reference value.

로 계산할 수 있다.In step (b), the harmonic emission limit for the non-linear facility for h (h is natural water) harmonics

Can be calculated as

Where E _Uhi Is the harmonic _emission limit of the nonlinear facility i for the h harmonics, G _hHV is the global level of the h harmonics in the high or ultra high voltage system, α is the harmonic synthesis index, S _t is the common coupling point (common coupling point Where the power can be supplied from the power system, the total available power of the system, S _i, is the rated capacity of the customer.

In order to limit the outflow of the nonlinear load on the consumer side, the method may further include calculating the harmonic outflow limit by dividing the harmonic outflow limit by the harmonic impedance for the nonlinear facility for the hth harmonic.

The method may further include supplying a normal load when the harmonic load capacity of the consumer is 0.1% or less of the short circuit capacity of the system or the consumer harmonic outflow prediction value is less than or equal to the consumer harmonic outflow threshold.

According to the embodiment of the present invention, it is possible to effectively manage the harmonics generated in the transmission system.

According to the embodiment of the present invention, the user can quickly evaluate and manage the harmonic emission limit of the consumer.

1 is a block diagram schematically showing a transmission system harmonic emission limit evaluation system according to an embodiment of the present invention.
2 shows assignment of compatibility levels according to the ratio of generator, transformer, and line impedance.
3 is a conceptual diagram schematically showing power inflow and outflow in a substation bus.
4 is a flowchart illustrating a transmission system harmonic emission limit evaluation method according to an embodiment of the present invention.

The present invention may be variously modified and have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In describing the present invention, when it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, numerals (eg, first, second, etc.) used in the description process of the present specification are merely identification symbols for distinguishing one component from another component.

In addition, in the present specification, when one component is referred to as "connected" or "connected" with another component, the one component may be directly connected or directly connected to the other component, but in particular It is to be understood that, unless there is an opposite substrate, it may be connected or connected via another component in the middle.

Hereinafter, a transmission system harmonic emission limit evaluation system and method according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram schematically showing a transmission system harmonic emission limit evaluation system according to an embodiment of the present invention. In the transmission system harmonic emission limit evaluation system according to an embodiment of the present invention, the customer harmonic load and the short-circuit capacity comparing unit 100, the customer harmonic emission limit measurement unit 200, and the customer harmonic prediction limit and harmonic emission limit comparison unit 300 are described. It includes.

Specifically, the customer harmonic load and the short-circuit capacity comparing unit 100 compare the customer's harmonic load capacity and the bus-line short-circuit capacity. The harmonic load capacity of the customer can be calculated by measuring the voltage and current of the customer connected to the power transmission system. The customer harmonic load and the short-circuit capacity comparator 100 calculate the maximum virtual power at which the distribution system is not disturbed, and calculates MVA by multiplying the current flowing through each part of the system by the system voltage.

At this time, the customer harmonic load and the short-circuit capacity comparing unit 100 allows power supply without calculating the harmonic current leakage limit separately when the customer's harmonic load capacity (S _Di ) is less than 0.1% of the system short-circuit capacity (S _c ). .

However, the customer harmonic load and short-circuit capacitance comparing unit 100 measures the current harmonic leakage threshold based on the global harmonic level when the customer's harmonic load capacity S _Di exceeds 0.1% of the system short-circuit capacitance S _c . Information may be transmitted to the harmonic leakage limit value 200.

On the other hand, according to an embodiment of the present invention, the real-time harmonic voltage and harmonic current of the customer can be measured and compared with the set reference value can be informed in real time whether the reference value of the customer's harmonic voltage and current.

The consumer harmonics outflow threshold measurement unit 200 may calculate the power supply capacity (S _t ) of the substation, the rated capacity (S _i ) of the customer, the global harmonic level (G _hHV ). The harmonic global level (G _hHV ) is the magnitude of the harmonic voltage applied when calculating the harmonic current flowing out from the consumer to maintain the planned level. In the transmission system, the harmonic global level (G _hHV ) applies 80% of the planned level. The planned level and the global level G _hHV will be described with reference to the drawings showing compatibility level assignments as shown in FIG. 2.

2 is a diagram illustrating assignment of compatibility levels according to the ratio of generator, transformer, and line impedance.

As shown in FIG. 2, HV (Medium Voltage), MV (Medium Voltage), and LV (Low Voltage) receive 30%, 45%, and 25% harmonic emission allocations according to the ratio of generator and transformer impedances. That is, the harmonics can flow out at the voltage level at the above ratio, and the planned level is determined within about 70% of the compatibility level because the information is 70% in the MV system including the LV.

The planned level and the global level of the transmission system harmonic emission limit evaluation system can be set as shown in Tables 1 and 2.

Planning level (HV) Odd-order harmonics (excluding triples) Odd-order harmonics (multiple multiples) Even Harmonics Order (h) Harmonic Voltage% Order (h) Harmonic Voltage% Order (h) Harmonic Voltage% 5 2.3 3 1.9 2 0.8 7 1.9 9 0.6 4 0.4 11 1.3 15 0.2 6 0.2 13 1.1 21 0.1 8 0.1 17 0.8 27 0.1 10 0.1 19 0.7 33 0.1 12 0.1 23 0.5 39 0.1 14 0.1 25 0.5 45 0.1 16 0.1 29 0.4 - - 18 0.1 31 0.4 - - 20 0.1 35 0.3 - - 22 0.1 37 0.3 - - 24 0.1 41 0.3 - - 26 0.1 43 0.2 - - 28 0.1 47 0.2 - - 30 0.1 49 0.2 - - 32 0.1 - - - - 34 0.1 - - - - 36 0.1 - - - - 38 0.1 - - - - 40 0.1 Total Harmonic Distortion (THD): 3%

Global level (HV) Odd-order harmonics (excluding triples) Odd-order harmonics (multiple multiples) Even Harmonics Order (h) Harmonic Voltage% Order (h) Harmonic Voltage% Order (h) Harmonic Voltage% 5 1.8 3 1.5 2 0.6 7 1.5 9 0.5 4 0.3 11 1.1 15 0.1 6 0.2 13 0.9 21 0.1 8 0.2 17 0.6 27 0.1 10 0.1 19 0.5 33 0.1 12 0.1 23 0.4 39 0.1 14 0.1 25 0.4 45 0.1 16 0.1 29 0.3 - - 18 0.1 31 0.3 - - 20 0.1 35 0.2 - - 22 0.1 37 0.2 - - 24 0.1 41 0.2 - - 26 0.1 43 0.2 - - 28 0.1 47 0.2 - - 30 0.1 49 0.2 - - 32 0.1 - - - - 34 0.1 - - - - 36 0.1 - - - - 38 0.1 - - - - 40 0.1

The customer harmonic outflow limit measurement unit 200 calculates the power supply capacity and the customer rated capacity S _t of the substation bus bar using Equation 1.

[Equation 1]

As shown in FIG. 3, the amount of power inflow and outflow in the substation bus is the same as the sum of the amount of power S _in flowing into the bus and the amount of power _out (S _out ) of the substation. The power supply capacity S _{t of} ) can be calculated.

At this time, if there is a facility such as a high voltage direct current (HVDC) or a static var compensator (SVC) in a new consumer supply substation, the power supply capacity of the substation bus bar, that is, the customer rated capacity (S _t ) May be calculated as in Equation 2.

[Equation 2]

HVDC or SVC is a facility that is applied to improve the reliability of the system, but since it is a device that generates harmonics in terms of power quality, the harmonic leakage limit of new customers is calculated by considering the capacity of HVDC and SVC as shown in Equation 2.

In real power systems, if multiple harmonic sources are linked to the same bus, the magnitude of the harmonics is generally less than the arithmetic sum of the maximum of each harmonic source. Therefore, the harmonic current limit value can be calculated using the harmonic synthesis index as shown in Equation (3).

&Quot; (3) "

Where E _Uhi Is the harmonic _emission limit of the nonlinear facility i for the h harmonics, G _hHV is the global level of the h harmonics in the high or ultra high voltage system, α is the harmonic synthesis index, S _t is the common coupling point (common coupling point The total available power of the system, where S _i can receive power from the power system, S _i The rated capacity of the customer can be calculated by applying the contract power (P _i ) and the contract power factor (cosΦ _i ).

Harmonic synthesis index (α) can be applied using Table 3.

Harmonic Synthesis Index (α) Harmonic order (h) One h <5 1.4 5≤h≤10 2 10 <h

In Table 3, when the phase of harmonics is within 90 °, the harmonic synthesis index (α) = 1 may be applied to the harmonics of the fifth order or higher.

On the other hand, the customer harmonic outflow limit measurement unit 200 calculated the harmonic outflow limit of the customer as shown in Equation 3 in order to maintain the harmonic voltage of the power system at a constant level, but substantially the harmonic outflow of the non-linear load on the customer side To limit, the harmonic current is calculated and applied. As described above, in order to calculate the harmonic leakage threshold as a harmonic current, a harmonic impedance (Frequency-Dependent Impedance) is used. Harmonic impedance is data provided by the supplier supplying power.

The customer harmonic leakage threshold using harmonic impedance is calculated as shown in Equation 4.

&Quot; (4) &quot;

Where E _ihi is the magnitude of the harmonic current that can flow out of the customer i for the hth harmonic, and Z _h is the harmonic impedance at the common coupling point.

The consumer harmonic prediction value and the harmonic outflow limit comparison unit 300 compares the consumer harmonic prediction value and the harmonic outflow limit value and requests a countermeasure for reducing harmonics to the consumer when the consumer harmonic prediction value exceeds the consumer harmonic outflow limit value (E _Uhi ).

On the other hand, the new customer can determine whether or not to connect to the grid by performing the harmonic emission limit evaluation when applying for connection, but the harmonic load may continue to change depending on the customer load configuration after the grid connection. Therefore, the harmonic current flowing out from the consumer to the power system after grid connection can be measured and analyzed based on Table 4, and a countermeasure can be requested if exceeded.

Measurement period Measures Breakdown 1 day 3 sec measurement 95% cumulative probability below runoff limit 1 week 10 minute reading Maximum value is below spill limit 1 week 3 sec measurement Maximum value is less than 1.5 times runoff limit

4 is a flowchart illustrating a transmission system harmonic emission limit evaluation method according to an embodiment of the present invention.

4, the customer harmonic load capacity and the short-circuit capacity input step (S100), the customer harmonic load capacity and the short-circuit capacity comparison step (S200), the customer harmonics outflow threshold calculation step (S300), the customer harmonics outflow prediction value and the customer harmonics outflow Comparing the threshold value (S400), the step of allowing power supply (S500) and the step of reflecting to the harmonic reduction equipment (S600).

Entering the customer harmonic load capacity and the short-circuit capacity input step (S100) inputs the calculated value of the customer's harmonic load capacity using the voltage value and current value of the customer connected to the power transmission system, or the customer harmonic load and short circuit shown in FIG. When the voltage value and the current value of the customer are input in the capacity comparison unit 100, the load capacity may be calculated using the capacity comparison unit 100. In addition, in the input of the customer harmonic load capacity and the short-circuit capacity (S100), the maximum virtual power value that does not interfere with the power distribution system is input as the short-circuit capacity value.

Meanwhile, according to an exemplary embodiment of the present invention, the method may further include determining, in real time, whether or not the customer's reference value of the harmonic voltage and current is exceeded after measuring the real-time harmonic voltage and the harmonic current of the customer.

Table 5 shows a comparison of the customer harmonic voltage reference value and measurement in real time, and Table 6 shows a comparison of the customer harmonic voltage reference value and measurement in real time. As shown in Table 5 and Table 6, it is possible to display the harmonic voltage and harmonic current in comparison with the reference value in real time.

Voltage evaluation Odd-order harmonics (excluding triples) Odd-order harmonics (multiple multiples) Even Harmonics Order (h) Reference value Measure result Order (h) Reference value Measure result Order (h) Reference value Measure result % % % 5 0.48 0.81 Excess 3 0.23 0.25 Excess 2 0.09 0.05 normal 7 0.40 0.28 normal 9 0.12 0.04 normal 4 0.05 0.02 normal 11 0.42 0.04 normal 15 0.05 0.08 Excess 6 0.04 0.02 normal 13 0.36 0.06 normal 21 0.04 0.05 Excess 8 0.02 0.02 normal 17 0.24 0.06 normal 27 0.02 4.00 Excess 10 0.03 0.02 normal 19 0.21 0.05 normal 33 0.02 0.04 Excess 12 0.03 0.01 normal 23 0.17 0.05 normal 39 0.02 0.02 Excess 14 0.03 0.01 normal 25 0.15 0.04 normal 45 0.02 0.01 normal 16 0.03 0.01 normal 29 0.13 0.06 normal - - 18 0.03 0.01 normal 31 0.12 0.04 normal - - 20 0.03 0.01 normal 35 0.10 0.02 normal - - 22 0.03 0.02 normal 37 0.09 0.01 normal - - 24 0.03 0.01 normal 41 0.08 0.01 normal - - 26 0.03 0.01 normal 43 0.07 0.01 normal - - 28 0.03 0.01 normal 47 0.07 0.01 normal - - 30 0.03 0.01 normal 49 0.06 0.01 normal - - 32 0.03 0.01 normal - - - - 34 0.03 0.02 normal - - - - 36 0.03 0.01 normal - - - - 38 0.03 0.01 normal - - - - 40 0.03 0.01 normal

Current evaluation Odd-order harmonics (excluding triples) Odd-order harmonics (multiple multiples) Even Harmonics Order (h) Reference value Measure result Order (h) Reference value Measure result Order (h) Reference value Measure result % % % 5 5.16 7.18 Excess 3 4.22 3.27 normal 2 2.53 0.20 normal 7 3.07 0.46 normal 9 0.72 0.50 normal 4 0.63 0.12 normal 11 2.04 1.28 normal 15 0.17 1.04 Excess 6 0.36 0.06 normal 13 1.48 2.52 Excess 21 0.09 0.44 Excess 8 0.27 0.05 normal 17 0.75 1.20 Excess 27 0.05 1.30 Excess 10 0.12 0.05 normal 19 0.59 0.38 normal 33 0.04 0.10 Excess 12 0.14 0.05 normal 23 0.39 0.87 Excess 39 0.03 0.18 Excess 14 0.12 0.05 normal 25 0.33 2.63 Excess 45 0.03 0.26 Excess 16 0.11 0.06 normal 29 0.23 0.35 Excess - - 18 0.09 0.05 normal 31 0.20 0.10 normal - - 20 0.08 0.05 normal 35 0.15 0.21 Excess - - 22 0.08 0.04 normal 37 0.13 0.16 Excess - - 24 0.07 0.07 Excess 41 0.10 0.31 Excess - - 26 0.06 0.09 Excess 43 0.09 0.24 Excess - - 28 0.06 0.04 normal 47 0.08 0.20 Excess - - 30 0.06 0.04 normal 49 0.07 0.15 Excess - - 32 0.05 0.04 normal - - - - 34 0.05 0.05 Excess - - - - 36 0.05 0.04 normal - - - - 38 0.04 0.04 normal - - - - 40 0.04 0.06 Excess

The input customer harmonic load capacity comparison step (S200) compares the customer harmonic load capacity and the short-circuit capacity. For example, when the customer's harmonic load capacity (S _Di ) is greater than 0.1% of the system short circuit capacity (S _c ), the process proceeds to step (S300) of calculating the customer harmonic outflow threshold. On the other hand, the harmonic load capacity of suyongga (S _Di) the system short-circuit capacity (S _c) when 0.1% or less in other words, the grid short circuit capacity of the harmonic load capacitance (SDi) of suyongga as shown in Equation 5 (S _c) as divided by the If less than 0.1% allow power supply (S500).

[Equation 5]

Then, suyongga calculated harmonic leakage limit step (S300) is calculated by using a harmonic leakage limits the power supply capacity (S _t), the rated capacity (S _i), the Global Harmonic rebelreul suyongga of the substation.

At this time, any one of the harmonic leakage thresholds calculated using Equations 1 to 4 may be used. Preferably, the value calculated using Equation 4 may be a harmonic leakage threshold.

Next, the consumer harmonics outflow prediction value and the consumer harmonics outflow threshold are compared. (S400) When the consumer harmonics outflow forecast value exceeds the consumer harmonics outflow threshold, the customer requests a countermeasure for reducing harmonics, for example, operation of a harmonic filter. (S600)

At this time, when the consumer harmonics outflow prediction value is less than the consumer harmonics outflow threshold, the power supply is allowed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the following claims And changes may be made without departing from the spirit and scope of the invention.

100: customer harmonic load and short-circuit capacity comparison unit
200: consumer harmonics outflow threshold measurement unit
300: consumer harmonic prediction and harmonic runoff threshold comparison unit
500: Mothership

Claims (13)

A capacity comparison unit for comparing the harmonic load capacity of the customer with the short circuit capacity of the system;
A customer harmonic outflow limit measurement unit for measuring a harmonic outflow limit when the harmonic load capacity of the consumer exceeds 0.1% of the short-circuit capacity of the system; And
The consumer harmonics outflow prediction value and the harmonics outflow threshold are compared with the customer harmonics outflow threshold.
Including
The consumer harmonics outflow threshold measurement unit
The harmonic emission limit for nonlinear installations for h (h is natural water) harmonics

Where E _Uhi is the harmonic _emission limit of the nonlinear facility i for h harmonics, G _hHV is the global level of h harmonics in the high or ultra high voltage system, α is the harmonic synthesis index, and S _t is the common coupling point ( common bond that has the power to use the customer power system where you can accept power from) the total power available in the grid, S _i is the will of the rated capacity of the suyongga, transmission system harmonic emission limits evaluation system.
The method of claim 1,
The capacity comparison unit
Transmission system harmonic emission limit evaluation system, characterized in that for calculating the harmonic load capacity of the customer receiving the voltage and current of the customer connected to the transmission line.
The method of claim 1,
The capacity comparison unit
Transmission system harmonic emission limit evaluation system that receives the voltage and current of the customer connected to the transmission line and compares with the set reference value to inform the voltage or current information exceeding the reference value.
delete The method of claim 1,
The harmonic synthesis index is
When the phase of the h-harmonic is within 90 °, the harmonic synthesis index is used for harmonics of 5 or more orders,
The harmonic synthesis index is 1, 5 and 10 when the harmonic order is less than 5, 1.4, 10 or more when the transmission system harmonic emission limit evaluation system, characterized in that applied.
The method of claim 1,
The consumer harmonics outflow threshold measurement unit
In order to limit the outflow of the nonlinear load on the consumer side, the harmonic emission limit value for the nonlinear facility for the h-th harmonic is divided by the harmonic impedance to calculate the customer harmonic emission limit value. .
The method of claim 1,
In the capacity comparison unit, the comparison value is that the harmonic load capacity of the customer is 0.1% or less of the short circuit capacity of the system,
A transmission system characterized in that the consumer harmonics outflow prediction value and the consumers harmonics outflow threshold are compared by the consumer harmonics prediction value and the harmonics outflow threshold value comparison unit to supply a normal load if the consumers harmonics outflow prediction value is less than or equal to the consumers harmonics outflow threshold. Harmonic emission limit evaluation system.
(a) comparing the customer's harmonic load capacity with the system's short circuit capacity;
(b) measuring a harmonic outflow threshold when said customer's harmonic load capacity exceeds 0.1% of said system's short-circuit capacity; And
(c) requesting a countermeasure against harmonics to the consumer when the consumer harmonic outflow prediction value exceeds the consumer harmonic outflow threshold by comparing the consumer harmonic outflow threshold and the consumer harmonic outflow prediction value of the consumer;
Including
Step (b) is
For the nonlinear facility for h (h is natural water) harmonics, the harmonic emission limit

Where E _Uhi is the harmonic _emission limit of the nonlinear facility i for h harmonics, G _hHV is the global level of h harmonics in the high or ultra high voltage system, α is the harmonic synthesis index, and S _t is the common coupling point ( common bond that has the power to use the full power available to customers, S _i of the grid at the position) that can be powered from a power system is rated to a capacity of, transmission system harmonic emission limits evaluation of suyongga.
The method of claim 8,
Step (a) is
And calculating the harmonic load capacity by receiving a voltage and a current of a customer connected to a transmission line.
The method of claim 8,
The transmission system harmonic emission limit evaluation method further comprising the step of receiving the voltage and current of the customer connected to the transmission line and comparing the set reference value and the voltage or current information exceeding the reference value.
delete The method of claim 8,
Calculating the customer harmonic outflow limit by dividing the harmonic outflow limit for the nonlinear facility for the hth harmonic by the harmonic impedance to limit the outflow of the nonlinear load on the consumer side
Transmission system harmonic emission limit evaluation method further comprising.
The method of claim 9,
And supplying a normal load when the customer's harmonic load capacity is 0.1% or less of the system's short-circuit capacity or the customer's harmonic outflow prediction value is less than or equal to the customer's harmonic outflow threshold.

Images