Microsoft Word - ETASR_V12_N3_pp8592-8596 Engineering, Technology & Applied Science Research Vol. 12, No. 3, 2022, 8592-8596 8592 www.etasr.com Le et al.: A Power Line Lightning Protection Method for Television and Radio Stations A Power Line Lightning Protection Method for Television and Radio Stations Quang Trung Le Engineering and Technology Department Lilama 2 International Technology College Dong Nai, Vietnam qtrungttc2@gmail.com Trong Nghia Le Electrical and Electronics Department HCMC University of Technology and Education Ho Chi Minh city, Vietnam trongnghia@hcmute.edu.vn Huy Anh Quyen Electrical and Electronics Department HCMC University of Technology and Education Ho Chi Minh City, Vietnam anhqh@hcmute.edu.vn Trieu Tan Phung Electrical and Electronics Department Cao Thang Technical College Ho Chi Minh City, Vietnam phungtrieutan@caothang.edu.vn Hong Hau Pham Engineering and Technology Department Lilama 2 International Technology College Dong Nai, Vietnam hauph.ute@gmail.com Received: 13 January 2022 | Revised: 25 March 2022 | Accepted: 1 April 2022 Abstract-The existing research on lightning protection focuses on risk assessment or equipment selection. There has not been any thorough research about lightning protection including risk assessment for a building in order to identify the risks when selecting lightning protection equipment according to technical requirements and cost optimization. The objective of the current paper is to propose a new risk computational method of damages by lightning for a Television and Radio Station (TRS). The new computational method consists of nine steps for identifying two risk indices, human life loss (R1) and service loss (R2). If the value of R1 is higher than the regulatory limit value RT1 and the value of R2 is higher than the regulatory limit value RT2, the damage risks due to lightning are very serious. Therefore, the TRS is necessary to select lightning protection solutions to reduce these risks. In addition, the paper proposes a six-step procedure for selecting and testing surge protective devices. The proposed calculations are then applied to a real TRS in Vietnam, and some testing results are simulated in Matlab-Simulink. Keywords-risk of damage by lightning; Lightning Protection System (LPS); Surge Protection Measures (SPM); Television and Radio Station (TRS) I. INTRODUCTION Power system development can cause many problems. The issue of maintaining and stabilizing the power system when there is a problem is always a topic of interest [1, 2]. There have been many studies regarding the assessment of the risk of damages by lightning to buildings [3, 5-7] and the guidelines for selecting and installing lightning protection equipment [4, 8, 9]. Based on the above, we propose an overall protection method for surge protective devices on power lines connected to the TRS including risk assessment, equipment selection, and installation for reducing the risks of damages caused by lightning. This overall method is proposed for applying Surge Protective Devices (SPDs) on power lines for a TRS in Vietnam. Based on the computation of the damage values of the TRS, the paper provides a solution for selecting SPDs suitable to the characteristics of the TRS. This research focuses on the risk values about the human life loss (R1) and service loss (R2). When these two indices are higher than the regulatory limit values, TRS must be installed with SPDs to reduce the risk of damage by lightning. Besides, the estimation of lightning protection level is performed by simulations in Matlab/Simulink. With the simulation results, it is possible to select the SPDs that satisfy with the real requirements of the TRS with a reasonable investment funding. II. A NEW COMPUTATION METHOD FOR SELECTING LIGHTNING SURGE PROTECTIVE DEVICES ON POWER LINES A. The Procedure for Assessing Risk Values for the TRS This section proposes a new computational method for identifying risk values R1 and R2 for a TRS. The method includes nine steps as shown in Figure 1. Corresponding author: Trieu Tan Phung Engineering, Technology & Applied Science Research Vol. 12, No. 3, 2022, 8592-8596 8593 www.etasr.com Le et al.: A Power Line Lightning Protection Method for Television and Radio Stations Fig. 1. Procedure for assessing the risk values for the TRS. • Step 1: Determine the parameters of the TRS encompassing height, length, width; height of antenna tower, degree of shielding by the structures around, density of lightning, measures of fire protection, installation method, and length of the power and service lines directly connected to the TRS, and the current lightning protection equipment. • Step 2: Compute the risk components by the lightning strikes direct and indirect to the TRS. Then, identify risk values R1 and R2. • Step 3: Collate risk values of the R1 and R2 with the RT1 and RT2 (regulatory limit values RT1 and RT2 are referenced to IEC 62305-2 [5]). If these risk values are bigger than RT1 and RT2, move to the step 4. • Step 4: Check if the TRS has been installed with Lightning Protection System (LPS) or not. If the TRS has not been installed with LPS, transfer to step 6. If the TRS has been installed with LPS, transfer to Step 5. • Step 5: Check if the TRS has been installed with Surge Protection Measures (SPM) on the power lines or not. If the TRS has been installed with LPS and SPM but the risk values of the R1 and R2 are still higher than RT1 and RT2 risk values, go to Step 8. If the TRS has not been installed with SPM, go to Step 7. • Step 6: Select a suitable LPS for installation and go to Step 9. • Step 7: Select a suitable SPM equipment on the power line for reducing the risk values and go to Step 9. • Step 8: Select additional SPM equipment and go to Step 9. • Step 9: Recompute R1 and R2 and go back to Step 3. TABLE I. RECOMMEND MAXIMUM LIGHTNING CURRENT Exposure level Low Medium High Environment of building The building is located in an urban/ suburban area. The building is located in plain. The building is located in areas where there is high lightning risk by the surrounding environment (pylons or mountainous regions, trees, wet areas, ponds, etc.) Recommended maximum lightning current (kA) 20 40 65 B. The Procedure for Testing and Installing SPDs Based the calculated values of R1 and R2, the procedure for selecting and testing SPDs is implemented in 6 steps, shown in Figure 2. Fig. 2. Procedure for testing and installing SPDs. • Step 1: Relying on the single-line diagram of power lines connected to the TRS, build a model of the electrical network in Matlab/Simulink including surge currents. • Step 2: Choose the SPDs for installing on the power lines. • Step 3: Identify the locations for installing the SPDs on the power lines for Essential Main Switchboard (EMSB) and Main Switchboard (MSB). Engineering, Technology & Applied Science Research Vol. 12, No. 3, 2022, 8592-8596 8594 www.etasr.com Le et al.: A Power Line Lightning Protection Method for Television and Radio Stations • Step 4: Simulate for checking the withstanding of the SPDs on the power lines with wave impulse 8/20µs. • Step 5: Check the protection voltage value (UP). The UP has to satisfy the requirements in (1) for electrical equipment [9] and in (2) for electronic devices [6]. If these requirements are not satisfied, the procedure goes back to Step 2. If these requirements are satisfied, go to Step 6. UP ≤ (1200+Un) (1) UP ≤ 1.5UN (2) • Step 6: The TRS is protected. III. COMPUTATION FOR A REAL TRS A. Characteristics of the Real TRS The studied TRS was built by reinforced concrete in an area with the lightning flash density of 13.7 strikes/km 2 /year without nearby higher buildings. The distance from the antenna tower to the station is 4m, and the height of the antenna tower is 55m. The length of the power lines connected to the station is 550m, and the telecom line is 960m. LPS is already installed, and the telecom lines are designed with SPM. However, the power lines are not protected by SPM. The TRS needs to calculate the R1 and R2 and then select for the SPD to be installed on the power lines B. Assessing the Damage Risk due to Lightning for the Studied TRS The followed steps of the proposed method are: • Step 1: Define the parameters of the TRS. • Step 2: Compute the risk values of R1 and R2. The results are shown in Table III. • Step 3: The risk value R2 is higher than the regulatory limit RT2 [5]. • Step 4: Class I LPS is installed in the TRS. • Step 5: The TRS is not yet installed with SPM on power lines. • Step 7: Select SPD with LPS class II. • Step 9: Recomputation of the risk values after installing the SPD. The results are shown in Table IV. After the SPD installation, the R1 and R2 risk values were less than the regulatory limit values [5]. Therefore, the TRS is protected and the risk of damages by lightning is limited. In addition, the effective protection of SPD on the power lines is implemented below. C. Implementing the Selection and Testing the Protection Level of SPD on the Power Lines The followed steps of the proposed method are: • Step 1: Based on the single-line diagram of the power lines connected to the TRS and the electric devices used in the TRS, the distribution network model is built in the Matlab as shown in Figure 3. TABLE II. TRS PARAMETERS Parameter Notation Value Density of ground flash (flashes/km 2 /year) Ng 13.7 Structure dimensions (m) L×W×H 12×8×10 Heigher of antenna tower t (m) Hanten 55 Location factor CD 1 Measures for protection pB 0.02 Coordinated SPDs PEB 0.01 Shield at external structure boundary KS1 1 Type of floor rt 10 -3 Probability of a dangerous discharge based on structure type Ps 0.2 Probability that lightning will cause a shock to animal or human being outside the structure due to touch and step voltage Ph 0.01 Measures of protection PTA 10 -2 Protection against touch voltages PTU 10 -2 Risk of fire rf 10 -3 Fire protection rp 0.2 Shield at internal structure boundary KS2 1 Hazard HZ 2 Loss of human life Due to touch and step voltage LT 10 -2 Due to physical damage LF 10 -2 Due to failure of the internal system LO - Loss of service Due to physical damage LF 10 -2 Due to failure of the internal system LO 10 -2 TABLE III. RISK VALUES BEFORE SPD INSTALLING Computed risk values Regulatory limit risk values Comparison R1=4.69×10 -6 RT1=10 -5 R1< RT1 R2=0.034 RT2=10 -3 R2> RT2 TABLE IV. RISK VALUES AFTER SPD INSTALLATION Computed risk values Regulatory limit risk values Comparison R1=7.753×10 -8 RT1=10 -5 R1< RT1 R2=0.00022 RT2=10 -3 R2